115: Melanocytic Nevi Flashcards
1
Q
What are the characteristics of melanocytic nevi?
A
Melanocytic nevi are benign neoplasms of melanocytes characterized by melanocytes in nests (>/= 3 melanocytes in direct contact) in the epidermis, dermis, or other tissues.
2
Q
What is the epidemiology of congenital melanocytic nevi (CMNs)?
A
Congenital melanocytic nevi (CMNs) occur in 1-3% of various ethnicities, with the majority being small to medium-sized. Tardive congenital nevi appear from 1 month to 2 years old and are most commonly found on the trunk and extremities, including the scalp and face.
3
Q
What are the clinical features associated with large and giant congenital melanocytic nevi (CMNs)?
A
Large and giant CMNs are associated with an increased risk of melanoma. They grow in proportion to the anatomical region and can be classified as follows:
Larger than acquired nevi, they may also present with hypertrichosis and various dermoscopic features.
Size Category | Size Range |
|—————|————-|
| Small CMNs | <1.5 cm |
| Medium CMNs | 1.5 - 20 cm |
| Large CMNs | 20 - 40 cm |
| Giant CMNs | >40 cm |
4
Q
What are the risk factors associated with congenital melanocytic nevi (CMNs)?
A
Risk factors for congenital melanocytic nevi (CMNs) include familial clustering and neurofibromatosis type 1, particularly for giant CMNs. The risk of melanoma is proportional to the number of melanocytes in the nevus, with larger and giant nevi having a greater risk.
5
Q
What are the key pathological features of congenital melanocytic nevi (CMNs)?
A
Pathological features of congenital melanocytic nevi (CMNs) include:
- Involvement of the entire skin from the junctional zone to the subcutis in large or medium-sized CMNs.
- Presence of small, round melanocytes in subcutaneous septae and progressively larger cells in the upper dermis.
- Propensity for cells to surround neurovascular bundles and appendageal structures.
- Junctional cells are usually larger than those beneath them, with basilar hyperpigmentation often observed.
6
Q
A patient has a large congenital melanocytic nevus (CMN) with satellite lesions. What is their lifetime risk of melanoma?
A
The lifetime risk of melanoma is 10-15% if the CMN is larger than 40 cm with satellite nevi.
7
Q
A patient with a giant congenital melanocytic nevus (CMN) develops seizures and increased intracranial pressure. What is the likely diagnosis?
A
The likely diagnosis is neurocutaneous melanosis, which involves melanocytes in the meninges or brain parenchyma.
8
Q
A patient has a nevus with a cobblestone pattern on dermoscopy. What type of nevus is this most likely to be?
A
This pattern is commonly seen in congenital melanocytic nevi (CMN).
9
Q
A patient presents with a nevus that has developed sensory symptoms. What is the concern, and what should be done?
A
The concern is melanoma. The lesion should be excised for histopathologic examination.
10
Q
A patient presents with a nevus that has developed focal hypopigmentation and atypical dots on dermoscopy. What is the concern, and what should be done?
A
These features may overlap with dysplastic nevi. The lesion should be biopsied for further evaluation.
11
Q
What are the histologic variations observed in congenital nevi that undergo neurotization?
A
Histologic variations include:
- Combined epithelioid cell (Spitz) phenotype: Often admixed with conventional round cell and neuroid elements.
- Elements of blue nevus: Either common or cellular type with heavily pigmented spindle-shaped melanocytic cells or features of inverted type-A or deep penetrating nevus.
- Proliferative nodules: Large, round hypercellular aggregates of melanocytes that blend with background nevus cells and contain mitotic figures, but have lower mitotic counts than melanoma.
12
Q
What is the epidemiology of nevus spilus?
A
The epidemiology of nevus spilus includes:
- Prevalence: 1% to 2% of the population.
- Onset: Present either at birth or in the first years of life.
- Type: Variant of congenital nevus.
- Demographics: No gender or ethnic predilection.
13
Q
What are the clinical features of nevus spilus?
A
Clinical features of nevus spilus include:
- Pigmentation: Darkly pigmented flat macules or papules within the nevus.
- Background pigmentation: Circumscribed and similar to a café-au-lait macule.
- Size variation: Tan macular background pigmentation can range from less than 1 cm to larger than 10 cm in diameter.
- Location: Most commonly found on the trunk and extremities.
- Dermoscopy findings: Dark speckled foci with a reticuloglobular pattern in a light brown background.
14
Q
What are the treatment options for nevus spilus?
A
Treatment options for nevus spilus include:
- Debulking: Large nevi can be debulked and smaller or medium-sized ones excised when feasible due to melanoma risk.
- Delay treatment: Recommended until after the first 6 months of life to reduce surgical and anesthetic risks.
- Surgical excision: Indicated for chronic pruritus, pain, or ulceration.
- Surveillance without excision: For clinically benign lesions based on appearance, size, and health issues.
- Destructive therapies: Such as dermabrasion and lasers do not address malignant potential.
15
Q
What are the complications associated with nevus spilus?
A
Complications associated with nevus spilus include:
- Changing lesions: Enlargement of dark macules or papules may require biopsy.
- Dysplastic nevus spilus: Irregularly shaped macules, sometimes with a central papule.
- Risk of melanoma: Larger, irregularly shaped areas with variegated pigmentation, particularly in larger segmental lesions greater than 40 cm.
16
Q
What is the etiology of nevus spilus?
A
The etiology of nevus spilus is characterized by:
- Postzygotic mutational event: Initiates a clonal field of melanocytes that are susceptible to creating multiple melanocytic tumors.
17
Q
A pediatric patient has a congenital melanocytic nevus (CMN) on the posterior midline of the neck. What associated condition should be considered, and what diagnostic test is recommended?
A
Neurocutaneous melanosis should be considered. An MRI of the brain or spinal cord concordant with the anatomic location of the nevus is recommended.
18
Q
A patient presents with a proliferative nodule in a congenital melanocytic nevus. What features differentiate it from melanoma?
A
Proliferative nodules are usually benign, with lower mitotic counts, less likelihood of ulceration, and fewer cytogenetic or epigenetic aberrations compared to melanoma.
19
Q
A patient presents with a nevus that has undergone neurotization. What histologic features are expected?
A
Histologic features include small S-shaped spindle cells forming thin, wavy fascicles with clefts containing mucin, and collections of neuroid cells forming pseudomeissnerian corpuscles.
20
Q
What are the clinical features of common acquired melanocytic nevi?
A
- Majority are less than 6 mm in size.
- Have a homogeneous surface and coloration, typically round to oval with sharply demarcated borders.
- Most are skin colored, pink, or brown; very dark brown or black nevi are unusual in light skin tones.
- Blue, gray, red, and white areas are atypical and may indicate melanoma.
- Papillomatous or dome-shaped nevi tend to be lighter in color with a dominant intradermal component.
- Flat lesions show more pigmentation and a robust junctional component.
- Nevi can appear anywhere on the skin surface, with specific patterns on palms and soles.
21
Q
What are the risk factors associated with the development of melanoma in patients with multiple nevi?
A
- UV radiation exposure.
- Male gender.
- Intermittent intense sun exposure.
- Genetic factors: size, frequency, and distribution patterns of acquired nevi tend to aggregate in families.
- History of frequent sunburns is a significant predictor of melanoma risk.
22
Q
What is the significance of the halo phenomenon in relation to melanocytic nevi?
A
- The halo phenomenon refers to the self-immunologic regression of a preexisting melanocytic nevus.
- It is characterized by a central pink or brown nevus surrounded by a symmetric round or oval halo of depigmented skin (less than 5 mm to 5 cm).
- The central nevus may lose its pigmentation and disappear, followed by gradual repigmentation of the area, indicating a potential immune response.
23
Q
What are the common characteristics of a junctional nevus as observed in diagnosis and pathology?
A
- A junctional nevus is typically:
- Circumscribed and mostly nested at the basal layer of the epidermis.
- Exhibits pale or pigmented cytoplasm with small, monomorphic nuclei and inconspicuous nucleoli.
- In some cases, nests of melanocytes are positioned toward the bases of rete ridges.
- Epidermal melanocytes between junctional nests are disposed as single typical cells along the basal layer, with overall numbers equal to or slightly greater than that in adjacent skin.
24
Q
A patient with a history of multiple sunburns presents with numerous nevi. What is their risk for melanoma, and what preventive measures should be taken?
A
The patient has an increased risk for melanoma due to the history of sunburns and numerous nevi. Preventive measures include minimizing UV radiation exposure, using sunscreen, and wearing protective clothing.
25
A patient with a history of immunosuppression develops multiple eruptive nevi. What types of nevi might these include, and what is the underlying association?
Eruptive nevi may include common acquired nevi, Spitz nevi, or blue nevi. They are associated with immunosuppression, neoplasia, or certain drugs.
26
A patient presents with a nevus spilus that has developed irregularly shaped macules with variegated pigmentation. What is the concern, and what should be done?
The concern is melanoma. A biopsy should be performed to evaluate the lesion.
27
A patient has a nevus on the nail apparatus with pigment extending onto the proximal nail fold. What is the likely diagnosis, and what should be done?
The pigment extension onto the proximal nail fold may indicate melanoma. The lesion should be biopsied for further evaluation.
28
A patient has a nevus with a central pink or brown lesion surrounded by a symmetric depigmented halo. What is the likely diagnosis, and what is the typical course?
The likely diagnosis is a halo nevus. The central nevus may lose its pigmentation and disappear, followed by gradual repigmentation of the entire area.
29
A patient has a nevus with a reticular and globular pattern on dermoscopy. What type of nevus is this most likely to be?
This pattern is commonly seen in acquired melanocytic nevi.
30
A patient presents with a nevus that has developed a red, scaly eczematous halo. What is the likely diagnosis, and what is the typical course?
The likely diagnosis is Meyerson’s nevus. Eczematous changes often self-resolve over the course of months.
31
A patient presents with a nevus on the sole of the foot that does not distort the skin surface. What is the likely explanation?
Nevi on the palms and soles may not distort the skin surface due to the thickness of the stratum corneum.
32
A patient has a nevus with a parallel-ridge pattern on dermoscopy. What is the concern, and what should be done?
The parallel-ridge pattern may indicate melanoma. The lesion should be biopsied for further evaluation.
33
A patient presents with a nevus that has developed a halo of depigmentation. What is the likely immunologic mechanism?
The halo phenomenon is due to self-immunologic regression of a preexisting melanocytic nevus.
34
A patient has a nevus with a lentiginous architecture and elongated rete pegs. What type of nevus is this most likely to be?
This is characteristic of a common junctional nevus.
35
A patient has a nevus with a homogenous surface and sharp borders. What type of nevus is this most likely to be?
This is characteristic of a common acquired melanocytic nevus.
36
A patient has a nevus with a reticuloglobular pattern on dermoscopy. What type of nevus is this most likely to be?
This pattern is commonly seen in nevus spilus.
37
A patient has a nevus with a fibrillar pattern on dermoscopy. What type of nevus is this most likely to be?
This pattern is commonly seen in nevi on the palms and soles.
38
A patient presents with a nevus that has developed a central papule with irregularly shaped macules. What is the concern, and what should be done?
The concern is dysplastic nevus spilus. A biopsy should be performed to evaluate the lesion.
39
What are the characteristics of balloon cell nevus?
Balloon cell nevus is a variant of common acquired nevus, composed of foam cells comprising a portion or all of a given lesion. It exhibits a maturation pattern and shows no cytologic atypia or significant mitotic activity.
40
What are the indications for the removal of benign-appearing lesions?
Indications for removal of benign-appearing lesions include:
1. Cosmetic concerns
2. Continual irritation
3. Worrisome clinical features that require histopathologic examination.
41
What is the significance of monitoring nevi in patients with numerous nevi or a family history of melanoma?
Patients with numerous nevi, dysplastic nevi, and a personal or family history of melanoma should be closely monitored due to an increased risk of melanoma associated with the number and size of nevi.
42
What are the recommended preventive measures against UVR overexposure?
Preventive measures against UVR overexposure include:
1. Confine outdoor activities to early morning or late afternoon/evening.
2. Avoid intense UVR exposure occurring 2 hours on either side of noon.
3. Wear cover-up clothing that blocks light transmission.
4. Consider Vitamin D supplementation for those practicing UVR avoidance.
43
What are the clinical features that may indicate possible melanoma in a nevus?
Clinical features that may indicate possible melanoma include:
- Pagetoid upward migration of cells in the epidermis
- Cytologic atypia of melanocytes (irregularity in size and shape, nuclear hyperchromasia)
- Failure of cells to mature in the deeper dermis
- Persistence of pigment production in the deep dermis
- Lack of symmetry
- Increased or deep dermal mitotic figures
- Focal areas of necrosis and desmoplasia or fibroplasia.
44
A 35-year-old patient presents with a nevus that has grown in size and developed irregular pigmentation. What steps should be taken to evaluate this lesion?
The lesion should be excised for histopathologic examination to rule out melanoma. Dermoscopy can also be used to differentiate benign from potentially malignant features.
45
What are the features indicating concern in the deeper dermis?
Persistence of pigment production, lack of symmetry, increased or deep dermal mitotic figures, focal areas of necrosis, and desmoplasia or fibroplasia.
46
What steps should be taken to evaluate a nevus that has grown in size and developed irregular pigmentation?
The lesion should be excised for histopathologic examination to rule out melanoma. Dermoscopy can also be used to differentiate benign from potentially malignant features.
47
What is the next step in management for a halo nevus with an asymmetric halo?
A biopsy is recommended for atypical-appearing central nevi, asymmetric halos, or eccentric placement of a melanocytic lesion within a halo.
48
What surveillance strategy is recommended for a patient with a history of melanoma and multiple dysplastic nevi?
Periodic examination and photographic surveillance are recommended to monitor for changes in the nevi.
49
What is the concern for a nevus that has developed focal areas of necrosis and desmoplasia?
The concern is melanoma. The lesion should be excised for histopathologic examination.
50
What are the histologic characteristics of a balloon cell nevus?
The balloon cell nevus is composed of foam cells comprising a portion or all of the lesion, with a maturation pattern evident and no cytologic atypia or significant mitotic activity.
51
What should be done for a nevus that has developed bridging of rete ridges and lamellar fibroplasia?
These features are associated with dysplastic nevi. The lesion should be biopsied for further evaluation.
52
What is the concern for a nevus that has developed ulceration and bleeding?
The concern is melanoma. The lesion should be excised for histopathologic examination.
53
What type of nevus is characterized by a monotonous similarity of nevomelanocytes in the dermis?
This is characteristic of a common acquired melanocytic nevus.
54
What is the term for a nevus with a neural phenotype?
This is referred to as a neural nevus.
55
What should be done for a nevus that has developed a limited pagetoid scatter?
Limited pagetoid scatter can indicate melanoma. The lesion should be biopsied for further evaluation.
56
What type of nevus is characterized by mucinous degeneration?
This is characteristic of a congenital pattern nevus.
57
What type of nevus is characterized by a foam cell composition?
This is characteristic of a balloon cell nevus.
58
What should be done for a nevus that has developed bridging of rete ridges and lymphocytic infiltrates?
These features are associated with dysplastic nevi. The lesion should be biopsied for further evaluation.
59
What is the prevalence of blue nevi in white and Japanese adults?
1% to 2% of white adults and 3% to 5% of Japanese adults.
60
What are the common clinical features of blue nevi?
Common blue nevi are small, deep-blue macules or papules less than 1 cm in diameter, often found on dorsal hands and feet, scalp, and buttocks. They exhibit a blue hue due to the Tyndall effect.
61
What are the related physical conditions associated with blue nevi?
Related physical conditions include Carney complex/LAMB syndrome and extensive dermal melanocytosis associated with phakomatosis pigmentovascularis.
62
What are the potential complications associated with blue nevi?
Complications include malignant blue nevus (melanoma) which may arise de novo or in contiguity with a cellular blue nevus.
63
What genetic mutations are associated with blue nevi?
GNAQ and GNA11 mutations are associated with blue nevi, while HRAS mutations are seen in 6% of deep penetrating nevi.
64
What is the underlying cause of the blue hue in a blue nevus?
The blue hue is due to the Tyndall effect, which is the refraction of light reflected from the nevus by the overlying dermis.
65
What is the risk of malignant transformation for a cellular blue nevus larger than 1 cm?
Cellular blue nevi have a risk of malignant transformation into melanoma, especially if they arise in contiguity with a cellular blue nevus.
66
What type of nevus is characterized by a targetoid appearance?
This is characteristic of a blue nevus.
67
What are the clinical features of Pigmented Spindle Cell Nevus?
Common in the 3rd decade of life, more frequent in females than males. 67% occur in lower extremities, especially the thigh. Characterized by sharply circumscribed darkly pigmented papules less than 7mm in diameter. Dermoscopically, most have streaks or pseudopods, described as a 'starburst appearance'; others may show a globular pattern with reticular depigmentation.
68
What is the histopathological characteristic of Spitz Nevus?
Characterized by melanocytic cells with large epithelioid nuclei and prominent nucleoli, surrounded by eosinophilic cytoplasm with a 'ground glass' appearance. Symmetric with progressive maturation increasing with depth. Presence of Kamino bodies, which are small intraepidermal eosinophilic globules that are PAS and diastase resistant. Pagetoid cells are commonly found in the center of the lesion.
69
What is the management approach for Pigmented Spindle Cell Nevus?
The management includes excision of the nevus. It is considered benign with no local recurrence or distant spread. There is no known prevention for this type of nevus.
70
What are the risk factors associated with Spitz Nevus?
HRAS mutation and genomic rearrangements involving ALK, ROS1, NTRK1, BRAF, RET, and MET. Combination of BAP1 loss and BRAF mutation increases the risk for cutaneous and uveal melanoma, mesothelioma, renal cell carcinoma, cholangiocarcinoma, and other malignancies.
71
What are the differential diagnoses for Pigmented Spindle Cell Nevus?
Differential diagnoses include:
| Diagnosis | Markers |
|----------|---------|
| Melanoma | Ki-67, Cyclin D1, Surviving |
| Spitz tumor | - |
| Blue nevus | - |
| Dysplastic junctional nevus | - |
| Combined nevomelanocytic/blue nevus | - |
| Hematoma | - |
72
A 35-year-old woman presents with a sharply circumscribed, darkly pigmented papule on her thigh measuring 6 mm in diameter. Dermoscopy reveals a starburst appearance. What is the most likely diagnosis, and what is the recommended management?
The most likely diagnosis is Pigmented Spindle Cell Nevus (Reed Nevus). The recommended management is excision, as it is benign with no risk factors or complications.
73
A pediatric patient presents with a new, red, dome-shaped papule on the face. The lesion is asymptomatic, hairless, and firm. What is the likely diagnosis, and what histological features would confirm it?
The likely diagnosis is Spitz Nevus. Histological features include large epithelioid nuclei with prominent nucleoli, progressive maturation with depth, and the presence of Kamino bodies.
74
A 25-year-old patient presents with a jet-black papule on the lower extremity. Dermoscopy reveals streaks and pseudopods. What is the diagnosis, and what histological features support it?
The diagnosis is Pigmented Spindle Cell Nevus (Reed Nevus). Histological features include fascicles of uniform pigment-synthesizing melanocytes with spindled appearance and pigment-laden macrophages in the dermis.
75
A 15-year-old patient presents with a widespread eruptive pattern of red dome-shaped papules. What is the diagnosis, and what genetic mutations are associated with it?
The diagnosis is Agminated Spitz Nevus. Associated genetic mutations include HRAS, ALK, ROS1, NTRK1, BRAF, RET, and MET.
76
A patient presents with a lesion showing genomic rearrangements involving ALK, ROS1, and NTRK1. What is the diagnosis, and what is the significance of these mutations?
The diagnosis is Spitz Nevus. These mutations are associated with the development of Spitz Nevus and may increase the risk of malignancies.
77
What are the characteristics of nodal nevi and their clinical significance?
Benign and present in lymph node capsule. Asymptomatic, often found incidentally due to lymph node removal. Cells may be deposited passively from cutaneous melanocytic lesions. May create difficulty in evaluation of SLN biopsies for patients with cutaneous melanoma. Histopathology shows nevomelanocytes largely confined to capsule or trabeculae with no cellular atypia and mitotic activity. Clinical significance: Misinterpretation of malignancy as benign can lead to under treatment.
78
What are the histopathological features of lentigo simplex?
Basilar melanocytic hyperplasia. Increased pigmentation within the epidermis. Slight to moderate elongation of rete ridges. Presence of melanophages in the papillary dermis. Melanin macroglobules may be present. Lymphohistiocytic infiltrate is present within the superficial dermis. Immunohistochemistry is not necessary for diagnosis.
79
What are the differential diagnoses for a lesion resembling a keloid, pyogenic granuloma, or spitzoid melanoma?
Keloid: Characterized by excessive collagen formation. Pyogenic granuloma: A benign vascular lesion that appears as a red bump. Spitzoid melanoma: A melanoma variant with atypical features such as: 1. Increased or atypical or deep mitoses 2. Asymmetry 3. Nuclear pleomorphism 4. Lack of maturation. Histopathological features include high Ki67 expression and negative p16 expression.
80
A 40-year-old patient has a benign lesion in the lymph node capsule discovered during a lymphadenectomy. What are the two main theories explaining the presence of nevomelanocytes in lymph nodes?
The two main theories are: (1) During embryonic development, melanoblasts get trapped in developing nodal tissues. (2) Passive transfer from cutaneous lesions to lymph nodes, such as through tattoo ink or radioactive colloid.
81
A 10-year-old child presents with multiple hyperpigmented macules on the skin and mucous membranes. The lesions are agminated and follow a curvilinear pattern. What is the likely diagnosis, and what syndromes should be considered?
The likely diagnosis is Lentigo Simplex. Syndromes to consider include LEOPARD syndrome and Peutz-Jeghers syndrome.
82
A patient presents with a benign lesion in the lymph node capsule. What histological features differentiate it from melanoma?
Histological features include nevomelanocytes confined to the capsule or trabeculae, absence of cellular atypia, and no mitotic activity.
83
A pregnant woman notices that her lentigines have become more conspicuous. What is the likely explanation, and what is the risk of malignant transformation?
The increased conspicuousness is likely due to hormonal changes during pregnancy. There is no increased risk of malignant transformation for lentigines.
84
A patient presents with a lesion showing melanin macroglobules in the dermis. What is the diagnosis, and what does this feature indicate?
The diagnosis is Lentigo Simplex. Melanin macroglobules indicate dysregulation of melanization.
85
What are the clinical features of solar lentigo?
Also known as actinic lentigo, sun-induced freckle, liver spot, lentigo senilis, senile lentigo. Hyperpigmented macules on photodamaged skin, either singly or as multiple lesions. Predominantly develops in older individuals, especially those with a history of sun exposure. Associated with conditions like XP, which leads to early development of solar lentigines in children. Histology shows elongation of rete ridges, hyperpigmentation, and dermal solar elastosis.
86
What are the histopathological characteristics of solar lentigo?
Elongated rete ridges extending into the papillary dermis with club-shaped or budlike endings. Epidermis between rete ridges may be atrophic with minimal overlying hyperkeratosis. Increased number of melanocytes that are hyperactive with markedly increased melanin production. Presence of horn cysts may result in overlap with seborrheic keratosis. Dermis shows solar elastosis and may have a scant to moderate perivascular chronic inflammatory infiltrate.
87
What are the risk factors associated with the development of solar lentigo?
Strongly associated with older age and cumulative sun exposure. History of facial ephelides (freckles) that may regress in the absence of sun exposure. Tanning capacity and concurrent use of oral contraceptive therapy. Chronic psoralen photochemotherapy may induce PUVA lentigines. Increased risk of UV-related cutaneous malignancies, including squamous cell carcinoma and melanoma.
88
What are the potential clinical implications of solar lentigo over time?
Solar lentigo may enlarge or darken, persist as a stable lesion, or regress. It may evolve into lichenoid keratosis or large cell acanthoma, which is associated with high expression of keratin 10 and lower expression of BCL-2. There is an increased risk of melanoma, which can emerge 15 years after initial therapy and continues to increase over time.
89
A 50-year-old patient presents with multiple hyperpigmented macules on sun-exposed skin. Histology shows elongated rete ridges and dermal solar elastosis. What is the diagnosis, and what are the associated risks?
The diagnosis is Solar Lentigo. Associated risks include an increased likelihood of UV-related cutaneous malignancies such as squamous cell carcinoma, basal cell carcinoma, and melanoma.
90
A patient with a history of chronic psoralen photochemotherapy presents with hyperpigmented macules on sun-protected sites. What is the likely diagnosis, and what factors contribute to its development?
The likely diagnosis is PUVA Lentigines. Contributing factors include the total number of treatments, male gender, fair skin, older age, and artificial sunbed use.
91
A 70-year-old patient presents with multiple hyperpigmented macules on photodamaged skin. Histology shows melanocytes with cellular atypia and nuclear pleomorphism. What is the diagnosis, and what are the histological features?
The diagnosis is Solar Lentigo. Histological features include elongated rete ridges, hyperactive melanocytes with increased melanin production, and dermal solar elastosis.
92
A patient presents with a lesion that has coalesced at a site of severe sun damage. What variant of solar lentigo might this represent, and what are its characteristics?
This might represent Ink Spot Lentigo, a variant with black pigmentation and irregular borders.
93
A patient with Type II diabetes presents with hyperpigmented macules on sun-exposed skin. What is the likely diagnosis, and what is the association with diabetes?
The likely diagnosis is Solar Lentigo. Type II diabetes has been independently associated with solar lentigo.
94
A patient presents with a lesion showing melanin-laden macrophages in the dermis. What is the likely diagnosis, and what does this histological feature indicate?
The likely diagnosis is Solar Lentigo. Melanin-laden macrophages indicate chronic photodamage.
95
A patient presents with a lesion showing increased expression of endothelin B receptor and endothelin 1. What is the diagnosis, and what does this expression indicate?
The diagnosis is Solar Lentigo. Increased expression of endothelin B receptor and endothelin 1 indicates melanocyte development and melanogenesis.
96
A patient presents with a lesion showing fibroblast-derived growth factors in the dermis. What is the diagnosis, and what role do these growth factors play?
The diagnosis is Solar Lentigo. Fibroblast-derived growth factors contribute to the formation of solar lentigo.
97
A patient presents with a lesion showing increased ROS production in keratinocytes. What is the diagnosis, and what is the role of ROS in this condition?
The diagnosis is Solar Lentigo. ROS production in keratinocytes leads to activation of MC1R and MITF in melanocytes, contributing to melanogenesis.
98
A patient presents with a lesion showing melanocytes with pseudoinclusions and multinucleation. What is the diagnosis, and what does this cellular atypia suggest?
The diagnosis is Solar Lentigo. This cellular atypia suggests chronic photodamage and increased melanocyte activity.
99
What are the common characteristics of dysplastic nevi?
Common in Caucasians. Flat or raised with smooth or 'pebbly' surface. Irregular shape, indistinct borders, variable pigmentation. Measure at least 5 mm in diameter. Frequently have a flat macular component, corresponding to a 'shoulder' or junctional component of a compound lesion. Absence of macular component and lesional symmetry suggest benignity. Often slightly raised, with a 'pebbly' or smooth texture. Predominantly found on trunk and upper back, but may also occur on sun-protected sites such as chest and buttocks.
100
What is the significance of UV exposure in the development of dysplastic nevi?
UV exposure is important for the development of dysplastic nevi. Sun exposure and sunburns, especially before the age of 20 years, have been associated with dysplastic nevi. Dysplastic nevi are more likely to involute in individuals who adhere to sun-protective measures.
101
What histopathological features are associated with dysplastic nevi?
Intraepidermal lentiginous melanocytic hyperplasia with cytologic and architectural atypia. Melanocytes are irregular in shape and distribution, often distributed singly and in nests. Pagetoid spread is noted at the level of the granular layer, more common in severely dysplastic nevi and melanoma. Atypical melanocytes may confluence along the epidermis, suggestive of melanoma in situ.
102
What factors influence the risk of developing melanoma in relation to dysplastic nevi?
The risk of developing melanoma is dependent on a combination of factors: 1. Number of dysplastic nevi 2. Personal history of melanoma or nonmelanoma skin cancer 3. Family history of melanoma 4. UVR exposure. For high-risk patients, intensive surveillance is recommended at 4 to 6 month intervals.
103
What is the recommended surveillance for patients with a family history of melanoma and multiple dysplastic nevi?
Annual surveillance is recommended for patients with a family history of melanoma and multiple dysplastic nevi. Surveillance should be initiated at 10 years of age for high-risk individuals with a family history of melanoma in at least 2 family members and a history of dysplastic nevi in the patient or a family member.
104
A 45-year-old patient presents with a flat lesion on the upper back with irregular borders and variable pigmentation. Histology reveals lentiginous melanocytic hyperplasia with cytologic atypia. What is the diagnosis, and what is the risk of malignant transformation?
The diagnosis is Dysplastic Nevus. The risk of malignant transformation to melanoma is dependent on factors such as the number of dysplastic nevi, personal and family history of melanoma, and UVR exposure.
105
A patient with a family history of melanoma and multiple dysplastic nevi is seeking advice. What surveillance measures should be recommended?
For high-risk individuals, surveillance should be initiated at 10 years of age. Annual surveillance is appropriate, and for severe cases, monitoring every 4-6 months is recommended.
106
A patient presents with a lesion showing bridging of melanocytic nests at the tips of rete ridges. What is the diagnosis, and what does this histological feature suggest?
The diagnosis is Dysplastic Nevus. Bridging of melanocytic nests at the tips of rete ridges suggests architectural atypia.
107
What surveillance measures should be recommended for high-risk individuals with a family history of melanoma?
Surveillance should be initiated at 10 years of age. Annual surveillance is appropriate, and for severe cases, monitoring every 4-6 months is recommended.
108
What is the diagnosis for a lesion showing bridging of melanocytic nests at the tips of rete ridges?
The diagnosis is Dysplastic Nevus.
## Footnote
Bridging of melanocytic nests suggests architectural atypia.
109
What is the significance of early sun exposure in a patient with multiple dysplastic nevi?
Early sun exposure and sunburns are significant risk factors for the development of dysplastic nevi.
110
What genetic mutations are commonly associated with dysplastic nevus syndrome that has developed melanoma?
Common genetic mutations include CDKN2A (encoding p16INK4a and p14ARK), BRAF, and loss of PTEN expression.
111
What is the diagnosis for a lesion showing pagetoid spread at the granular layer?
The diagnosis is Dysplastic Nevus.
## Footnote
Pagetoid spread indicates severe cytologic atypia and is more commonly seen in melanoma.
112
What factors determine the risk of developing additional melanomas in a patient with a history of melanoma?
Risk factors include the number of dysplastic nevi, personal history of melanoma or nonmelanoma skin cancer, family history of melanoma, and UVR exposure.
113
What is the diagnosis for a lesion showing melanocytes distributed singly and in nests at the tips and sides of rete ridges?
The diagnosis is Dysplastic Nevus.
## Footnote
This distribution suggests lentiginous melanocytic hyperplasia.
114
What is the diagnosis for a lesion showing dusty cytoplasm and nuclear pleomorphism in melanocytes?
The diagnosis is Dysplastic Nevus.
## Footnote
This cytologic atypia suggests a higher risk of malignant transformation.
115
What is the diagnosis for a lesion showing elongated rete ridges and a normal epidermal thickness?
The diagnosis is Dysplastic Nevus.
## Footnote
Elongated rete ridges indicate architectural atypia.
116
What is the diagnosis for a lesion showing a 'shouldering' junctional component of atypical melanocytes?
The diagnosis is Dysplastic Nevus.
## Footnote
The 'shouldering' component suggests extension of atypical melanocytes beyond the dermal component.
117
What is the diagnosis for a lesion showing confluence of atypical melanocytes along the epidermis?
The diagnosis is Melanoma in situ.
## Footnote
Confluence of atypical melanocytes suggests severe architectural atypia.
118
What is the diagnosis for a lesion showing a high proliferative rate and loss of PTEN expression?
The diagnosis is Dysplastic Nevus.
## Footnote
A high proliferative rate and loss of PTEN expression suggest a higher risk of malignant transformation.
119
What is the most common site of malignant transformation in melanoma?
The trunk is the most common site of malignant transformation in melanoma.
120
What are some factors associated with an increased risk of melanoma?
Factors include AIDS, renal transplantation, chronic myeloid leukemia, chemotherapy for pre-B cell acute leukemia, cutaneous phenotype, solar injury, and presence of ephelides (freckles).
121
How does dermoscopy enhance melanoma detection?
Dermoscopy increases the diagnostic accuracy of melanoma detection.
122
What are some recommended preventive measures for melanoma?
Recommended measures include sun protective measures, self-examination, and family screening.
123
What is the significance of excision in the management of dysplastic nevi?
Excision is appropriate; however, removal of dysplastic nevi does not significantly reduce the lifetime risk of melanoma.
## Footnote
Re-excision may be necessary to obtain a 5 mm margin if dysplastic nevi with severe atypia is identified on histology.
124
What impact do sun protective measures have on the incidence of nevi?
Sun protective measures reduce the incidence of dysplastic and common acquired nevi.
125
What are the common associations and risk factors for melanoma in a 60-year-old patient with a lesion on the trunk that has undergone malignant transformation?
Common associations include AIDS, renal transplantation, chronic myeloid leukemia, and chemotherapy for pre-B cell acute leukemia. Risk factors include cutaneous phenotype, solar injury, and the presence of ephelides (freckles).
126
What diagnostic tools can increase the accuracy of melanoma detection?
Diagnostic tools include dermoscopy, total body photography or mole mapping, Raman spectroscopy, confocal microscopy, multispectral imaging, and gene expression profiling.
127
What is the most common site for malignant transformation of dysplastic nevi?
The trunk is the most common site for malignant transformation of dysplastic nevi.
128
What is the association between chemotherapy for pre-B cell acute leukemia and melanoma risk?
Chemotherapy for pre-B cell acute leukemia is associated with an increased risk of melanoma.
129
What is the role of gene expression profiling in suspected melanoma?
Gene expression profiling helps in the accurate diagnosis and classification of melanoma.
130
What are the components that all types of blue nevi include?
1. Deeply pigmented dendritic melanocytes
2. Spindled and less pigmented melanocytes
3. Oval melanocytes
4. Melanophages
5. Fibrotic stroma
131
What is the defining characteristic of a cellular blue nevus?
Cellular blue nevus is characterized by vertically oriented dumbbell-shaped masses of melanocytes that protrude into the subcutis, with superficial dermis containing fibrotic stroma and larger streaming aggregates of oval melanocytes with scant melanin.
132
What is the clinical significance of the sudden appearance of a new nodule in a blue nevus?
The sudden appearance of a new nodule, enlargement of an existing nevus, or a large or atypical clinical appearance should prompt histopathologic examination due to the small risk of malignant transformation.
133
What are the treatment recommendations for cellular blue nevi?
1. Evaluate for excision due to the small risk of malignant transformation.
2. Excision should include subcutaneous fat to ensure removal of deeper melanocytic components.
3. Some dermatopathologists advocate complete removal of deep penetrating nevi, while others regard clinical removal as sufficient.
134
What are the characteristics of LEOPARD syndrome?
LEOPARD syndrome includes:
- L-entigines
- E-cg abnormalities
- O-cular hypertelorism
- P-ulmonary valve stenosis
- A-bnormalities of genitalia
- R-etardation of growth
- D-eafness, sensorineural
## Footnote
It is characterized by hundreds of lentigines during childhood and can develop on the genitalia, conjunctivae, palms & soles, and oral cavity.
135
What are the key features of Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome is characterized by:
- Commonly presents on the lips, buccal mucosa, perioral skin, palms, and soles.
- Cutaneous lentigines may fade at puberty, while oral lentigines may persist into adulthood.
136
What is the clinical course and prognosis of blue nevi?
Blue nevi are generally considered benign. However, an adverse prognostic event is the development of melanoma within one. Melanomas associated with or mimicking cellular blue nevi have a high propensity for the scalp and are linked to GNA11 mutations with loss of BAP1 expression.
137
What is the clinical presentation of lentigines in centrofacial lentiginosis?
In centrofacial lentiginosis, lentigines are characteristically distributed in a horizontal band across the face.
138
A patient presents with a sudden appearance of a new nodule on an existing blue nevus. What should be the immediate clinical action?
The sudden appearance of a new nodule, enlargement of an existing nevus, or a large or atypical clinical appearance should prompt histopathologic examination.
139
What histological features differentiate a cellular blue nevus from a common blue nevus?
A cellular blue nevus has vertically oriented dumbbell-shaped masses of melanocytes that protrude into the subcutis, larger streaming aggregates of oval melanocytes with scant melanin, and may show atypical mitotic figures, necrosis, or lymphocytic infiltrates. In contrast, a common blue nevus is an inverted dermal wedge-shaped mass with pigmented dendritic melanocytes admixed with melanophages within a fibrotic stroma.
140
What are the defining histological components of all types of blue nevi?
All types of blue nevi include deeply pigmented dendritic melanocytes, spindled and less pigmented melanocytes, oval melanocytes, melanophages, and fibrotic stroma.
141
A lesion is found to have nests of large, oval melanocytes with abundant, pale vacuolated cytoplasm and dusty melanin. What is the likely diagnosis?
The lesion is likely a deep penetrating nevus, which is characterized by nests of large, oval melanocytes with abundant, pale vacuolated cytoplasm and dusty melanin.
142
What is the recommended treatment for pigmented epithelioid melanocytoma occurring in a sporadic setting?
Pigmented epithelioid melanocytoma occurring in a sporadic setting is typically treated similar to melanoma, with wide excision and sentinel lymph node biopsy.
143
What are the clinical features of Laugier-Hunziker syndrome?
Laugier-Hunziker syndrome predominantly occurs on the lips, hard and soft palate, fingers, nail matrix, and palms. It infrequently appears on the genitalia and conjunctivae.
144
What are the key features of LEOPARD syndrome?
LEOPARD syndrome is characterized by lentigines, ECG abnormalities, ocular hypertelorism, pulmonary valve stenosis, abnormalities of genitalia, retardation of growth, and sensorineural deafness.
145
What histological findings in a cellular blue nevus raise concern for melanoma?
The presence of cells with large central nucleoli, more than a few mitotic figures per section, atypical mitotic figures, necrosis, or lymphocytic infiltrates raises concern for melanoma in a cellular blue nevus.
146
What is the clinical significance of melanomas associated with cellular blue nevi?
Melanomas associated with or mimicking cellular blue nevi have a high propensity for the scalp and a high frequency of GNA11 mutations with loss of BAP1 expression.
147
What is the histological hallmark of a compound blue nevus?
A compound blue nevus is characterized by dendritic melanocytes in increased number along the dermal-epidermal junction.
148
What is the typical distribution of centrofacial lentiginosis?
Centrofacial lentiginosis is characteristically distributed in a horizontal band across the face.
149
What are the histological features of pigmented epithelioid melanocytoma?
Pigmented epithelioid melanocytoma is characterized by mostly dermal nodular and sheet-like proliferation of enlarged epithelioid melanocytes with round nuclei, conspicuous nucleoli, and heavily pigmented cytoplasm, along with numerous admixed melanophages.
150
What is the recommended treatment for cellular blue nevi to prevent malignant transformation?
Cellular blue nevi should be evaluated for excision because of the small risk of malignant transformation. Excision should include subcutaneous fat to ensure removal of the deeper melanocytic components.
151
What are the staining characteristics of blue nevi?
Blue nevi stain positive with S100, stain strongly with Melan A/Mart-1, and are positive for HMB-45.
152
What are the clinical features of Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome commonly presents with lentigines on the lips, buccal mucosa, perioral skin, palms, and soles. Cutaneous lentigines may fade at puberty, while oral lentigines may persist into adulthood.
153
What is the clinical course and prognosis of blue nevi?
Blue nevi are generally benign. However, an adverse prognostic event is the development of melanoma within one.
154
What is the histological hallmark of a common blue nevus?
A common blue nevus is characterized by an inverted dermal wedge-shaped mass in which pigmented dendritic melanocytes are admixed with melanophages within a fibrotic stroma.
155
What are the clinical features of LAMB syndrome?
LAMB syndrome is characterized by lentigines, atrial myxoma, mucocutaneous myxomas, and blue nevi, which occur on the face, trunk, and genitalia.
156
What is the histological hallmark of a deep penetrating nevus?
A deep penetrating nevus has a tendency to extend through most of the thickness of the dermis, with some lesions reaching the superficial subcutis. It is often wedge-shaped, with the apex surrounding a folliculosebaceous unit.
157
What are the histological features of the superficial dermis in cellular blue nevi?
The superficial dermis in cellular blue nevi contains fibrotic stroma in which there are dendritic melanocytes and macrophages.
158
What is the significance of histopathologic examination in blue nevi?
Histopathologic examination is crucial when there is a sudden appearance of a new nodule, enlargement of an existing nevus, or a large or atypical clinical appearance, as these may indicate malignant transformation.
159
What is the defining component of cellular blue nevi?
The defining component of cellular blue nevi is the presence of larger streaming aggregates of oval melanocytes with scant melanin.
160
What is the clinical management of deep penetrating nevi?
Some dermatopathologists advocate complete removal of deep penetrating nevi, but others regard clinical removal as sufficient.
161
What are the histological features of melanophages in blue nevi?
Melanophages in blue nevi are histologically characterized by their presence within a fibrotic stroma, often admixed with pigmented dendritic melanocytes.
162
What are the histological features of oval melanocytes in blue nevi?
Oval melanocytes in blue nevi are less pigmented and are a defining component of cellular blue nevi, often forming larger streaming aggregates.
163
What is the clinical significance of GNA11 mutations in melanomas associated with cellular blue nevi?
GNA11 mutations in melanomas associated with cellular blue nevi are significant because they are often accompanied by loss of BAP1 expression and are associated with a high propensity for the scalp.
164
What are the histological features of fibrotic stroma in blue nevi?
The fibrotic stroma in blue nevi often contains dendritic melanocytes and melanophages, and it is a common feature across different types of blue nevi.
165
What is the clinical presentation of lentigines in LEOPARD syndrome?
In LEOPARD syndrome, lentigines appear in hundreds during childhood and develop on the genitalia, conjunctivae, palms, soles, and oral cavity.
166
What is the clinical presentation of lentigines in Peutz-Jeghers syndrome?
In Peutz-Jeghers syndrome, lentigines commonly present on the lips, buccal mucosa, perioral skin, palms, and soles.
167
What is the clinical presentation of lentigines in LAMB syndrome?
In LAMB syndrome, lentigines occur on the face, trunk, and genitalia.
168
What is the clinical presentation of lentigines in Laugier-Hunziker syndrome?
In Laugier-Hunziker syndrome, lentigines predominantly occur on the lips, hard and soft palate, fingers, nail matrix, and palms, and infrequently on the genitalia and conjunctivae.
169
What is the clinical significance of histopathologic examination in cellular blue nevi?
Histopathologic examination is significant in cellular blue nevi to evaluate for excision due to the small risk of malignant transformation.
170
What is the clinical significance of sentinel lymph node biopsy in pigmented epithelioid melanocytoma?
Sentinel lymph node biopsy is significant in pigmented epithelioid melanocytoma as it is treated similarly to melanoma, requiring wide excision and lymph node evaluation.
171
What is the clinical significance of excision in cellular blue nevi?
Excision in cellular blue nevi is significant to ensure removal of deeper melanocytic components and to mitigate the small risk of malignant transformation.
172
What is the clinical significance of wide excision in pigmented epithelioid melanocytoma?
Wide excision in pigmented epithelioid melanocytoma is significant as it is treated similarly to melanoma to prevent recurrence or metastasis.
173
What is the clinical significance of fibrotic stroma in blue nevi?
Fibrotic stroma in blue nevi provides a structural framework and often contains dendritic melanocytes and melanophages, which are key histological features.
174
What is the clinical significance of dusty melanin in deep penetrating nevi?
Dusty melanin in deep penetrating nevi is a histological feature that helps differentiate it from other types of nevi.
