Melanoma Flashcards
An otherwise healthy 2-year-old male infant is evaluated because of a congenital melanocytic nevus on his flank. Physical examination shows a hairy, 10 x 5-cm nevus with areas of dark brown pigmentation that is growing proportionate to the infant’s growth rate. He has another nevus, which measures less than 2 cm, on his arm. Which of the following is the primary indication for excision?
A) Dark color B) Growth rate C) Presence of hair D) Presence of two lesions E) Size of lesion
The correct response is Option E.
The primary indication for excision in this case is the 10-cm measurement in greatest dimension. This makes this congenital nevus a giant nevus. The exact definition of a giant nevus has been debated, but one of the most constant definitions is a nevus that is 20 cm in greatest dimension in an adult or a nevus that will become 20 cm in greatest dimension once the child is fully grown. This latter measurement usually translates to approximately a 9-cm nevus on the head and neck, or approximately a 6-cm nevus on the body of an infant. Other definitions of giant nevi include a nevus that is about 1% of the body surface area in the head and neck region or 2% of the body surface area in the trunk region, a nevus that is greater than 100 cm2 in area, or a nevus that cannot be excised in one stage. The main indication for excision in these giant congenital nevi is the malignant potential that they harbor. The rates of malignant degeneration are also a matter of great debate, with rates quoted anywhere from 0 to 40%. More recently, however, rates of less than 5% are quoted.
The other clinical features are not risk factors that indicate excision of the nevus. If a patient has more than three nevi, that potentially does increase the risk for malignant melanoma in the patient; however, this patient has only two.
2018
A 35-year-old primigravid woman at 10 weeks’ gestation is diagnosed with a 1.5-mm deep melanoma of the right cheek. Lymphoscintigraphy is planned. Which of the following is the most appropriate treatment of this patient?
A) Wide local excision during general anesthesia with 0.5-cm margins and concurrent sentinel node biopsy
B) Wide local excision during general anesthesia with 1-cm margins and concurrent sentinel node biopsy
C) Wide local excision during general anesthesia with 2-cm margins and concurrent sentinel node biopsy
D) Wide local excision during local anesthesia with 0.5-cm margins and second trimester sentinel node biopsy
E) Wide local excision during local anesthesia with 1-cm margins and second trimester sentinel node biopsy
The correct response is Option E.
The most recent guidelines for nonobstetric surgery during pregnancy from the American College of Obstetricians and Gynecologists Committee on Obstetric Practice (2011) recommend performing nonurgent surgery in the second trimester to minimize the risk of preterm contractions and spontaneous abortion. For patients and physicians who consider these risks unacceptable, then wide local excision with administration of a local anesthetic agent after preoperative lymphoscintigraphy, with delayed sentinel node biopsy during general anesthesia, after delivery, is recommended. For a 1.5-mm melanoma, the excision margin is 1 cm.
2018
A fair-skinned 55-year-old man is evaluated because of an irregular dark lesion on his back. Patient history includes frequent sunburn. On examination, the lesion is 8 mm in size, dome-shaped, dark, and has the appearance of a blood blister. The border of the lesion does not appear irregular. A biopsy of the lesion shows a well circumscribed proliferation of atypical melanocytes extending vertically throughout the dermis. There is no lateral extension of the intra-epidermal component. Which of the following is the most likely melanoma subtype?
A) Acral lentiginous B) Desmoplastic C) Lentigo maligna D) Nodular E) Superficial spreading
The correct response is Option D.
The most likely subtype of melanoma in this patient is nodular. Nodular melanomas are the second most common subtype (10 to 20%) and are commonly seen in the trunk, head, and neck with a slightly increased incidence in men. Upon invading the dermis, these lesions have a rapid vertical growth phase compared to the radial growth phase of the superficial spreading subtypes. These lesions are often dark and dome-shaped and have the appearance of a blood blister. They have increased metastatic potential. Histologic examination shows a sharply circumscribed epidermal component and extensive dermal proliferation with atypical melanocytes.
The superficial spreading subtype is characterized by lateral spreading of malignant melanocytes in the epidermis. This is the most common subtype and exhibits a prolonged radial growth phase before developing a vertical component. These lesions occur usually on sun-exposed skin and often arise in preexisting nevi. They appear flat and become irregular or raised with growth.
Lentigo maligna is a rare form of melanoma with low malignant potential. They often arise from lentigo maligna lesions and grow slowly in a radial fashion before a vertical phase. They are more common in older women and have a strong correlation to sun exposure. They are often present in the face, head, and neck as large, tan lesions with convoluted patterns.
Acral lentiginous melanoma is more common in dark-skinned patients and is often found on the palms, nail bed, and soles of the feet. These lesions are aggressive and frequently metastasize.
Desmoplastic melanoma is also a rare subtype with aggressive local growth; however, these lesions rarely metastasize. They are similar in appearance histologically to spindle cell tumors and are confused with common nevi, Spitz nevi, or hemangiomas.
2017
A 63-year-old man is evaluated because of a 1.6-cm pigmented lesion on his right shoulder. Excisional biopsy shows superficial spreading malignant melanoma with a Breslow depth of 3 mm. Evidence of distant metastases to which of the following tissues on further staging carries the poorest prognosis for this disease?
A) Liver
B) Lung
C) Lymph nodes
D) Subcutaneous tissue
The correct response is Option A.
The American Joint Committee on Cancer (AJCC) revised TNM staging of melanoma in 2010. Three subgroups of distant metastases are distinguished: skin and soft-tissue metastases (best prognosis), lung metastases (intermediate prognosis), and other visceral metastases such as liver and brain (worst prognosis). Elevated lactate dehydrogenase in either of the first subgroups up-stages to the last subgroup.
2017
A 4-year-old boy undergoes evaluation of a large congenital melanocytic nevus of the scalp affecting 40% of the surface area. Results of a recent biopsy in the center of the lesion showed diffuse areas of severe dysplasia. Which of the following is the most appropriate management?
A) Serial excision, linear closure
B) Single-stage excision, latissimus dorsi musculocutaneous free flap, skin grafting
C) Single-stage excision, rotational flap closure
D) Tissue expansion, excision, closure
E) Observation
The correct response is Option D.
This patient’s congenital nevus involves 40% of his scalp and has areas of severe dysplasia. Although the lifetime risk of malignant transformation in giant nevi as a whole is approximately 4%, the presence of biopsy-proven severe dysplasia at this young age mandates a more aggressive approach to management than observation. Complete removal of the nevus with reconstruction of the scalp is recommended to prevent malignant conversion. Although serial excision is useful and often preferred for moderate sized lesions, this nevus is far too big to completely excise and close in that fashion. Moreover, the intervals between stages would require more time than tissue expansion, and with the degree of dysplasia present in this patient, this is risky. Similarly, it is dubious if a nevus this size could be successfully excised and closed in one stage using only rotational flaps. In addition, this would alter the direction of the hair. The use of a free flap is far too extreme in the absence of a frank malignancy (which this is not) and would leave this child with a large bald area. The best option is tissue expansion, followed by complete excision and closure, which was successfully employed in this case.
2017
A 62-year-old man has a lesion of the left pinna. Examination of a specimen obtained on biopsy shows a 2.01-mm-thick melanoma with no ulceration, 11 mitoses, and a positive deep margin. The surgeon’s decision to perform sentinel node biopsy is most heavily influenced by which of the following factors?
A) Breslow thickness B) Head and neck location C) Lack of ulceration D) Number of mitoses E) Positive deep margin
The correct response is Option A.
Head and neck melanomas in general were thought to be distinct from other anatomic sites. Clearly there can be reconstructive and functional issues that are unique, such as in an ear melanoma.
In general the first Multicenter Selective Lymphadenectomy Trial (MSLT-1) concluded that for intermediate-thickness melanoma (1-4 mm), the status of the sentinel node was the most powerful predictor of outcome.
In an interim report in 2006, well before the final report in 2014, the specifics on what percentage of patients had melanoma of the head and neck in the MSLT-1 trial were not described, but what was reported was a lower rate of identification of a sentinel node in the neck versus lesions that mapped to the groin or axilla. This led many to conclude that the utility of the sentinel node biopsy in the head and neck was in question. More recent data from multiple high-volume institutions have concluded that identification of the sentinel node for head and neck melanoma is as accurate as other sites in the body, including similar false-negative rates and impact on prognostication.
Mitotic rate does not affect staging above 1-mm thick lesions, and although ulceration can, it does not influence the rationale to perform a sentinel node biopsy in intermediate thickness tumors. In thinner melanomas, a positive deep margin may be an indication for a sentinel node biopsy, but not for a tumor greater than 1-mm thick. The fact that lymphoscintigraphy may map the sentinel node to the parotid region means that the surgeon should be prepared to do a parotidectomy with facial nerve preservation, although recently less-invasive techniques have been described.
2017
A 55-year-old man undergoes biopsy of a pigmented lesion on the neck. Examination of a biopsy specimen shows superficial spreading of a malignant melanoma with no ulceration, 1.2-mm thickness, and less than 1 mitosis per mm2. In addition to wide local excision, which of the following is most appropriate treatment?
A) Interferon therapy B) Radiation therapy C) Regional lymphadenectomy D) Sentinel lymph node biopsy E) Observation
The correct response is Option D.
According to National Comprehensive Cancer Network guidelines, melanomas with Breslow thickness greater than 1 mm should be treated with wide local excision and sentinel lymph node biopsy.
Wide local excision alone, with no additional lymph node sampling, may be appropriate for some melanomas less than 1 mm, but additional factors such as mitotic rate and ulceration should be assessed.
Random lymph node sampling would not necessarily assess the first node in the draining basin, therefore, it is important that the sentinel lymph node be identified with techniques such as tracking of an intradermally injected radionucleotide using a handheld gamma probe and visual identification with blue dye.
In the past, melanomas with thickness between 1 and 4 mm were treated with elective lymph node dissection. Since several randomized, prospective studies failed to clearly demonstrate a survival advantage and the significant associated morbidity, sentinel lymph node biopsy has replaced this procedure.
While there are growing indications for the use of radiation therapy for skin cancers, intraoperative radiation therapy is not routinely used.
2016
A 48-year-old right-hand–dominant man is referred for treatment of a biopsy-proven subungual malignant melanoma in situ of the right thumb. Which of the following is the most appropriate treatment?
A) Amputation to the interphalangeal joint with no reconstruction
B) Amputation to the metacarpophalangeal joint with toe-to-thumb transfer
C) Chemotherapy
D) Radiation therapy
E) Wide local excision with split-thickness skin grafting
The correct response is Option E.
While the literature lacks randomized control data, there is mounting evidence that melanoma in situ can be appropriately treated with wide local excision alone. This is associated with considerably less morbidity than amputation with or without reconstruction. Radiation therapy or chemotherapy are not appropriate treatment options for malignant melanoma in this setting.
2016
A 2-month-old female infant is evaluated because of a pigmented skin lesion on the midline lumbar region. Physical examination shows a dark brown lesion that is 10 cm in diameter with an irregular surface and coarse hairs. This patient is at increased risk for which of the following?
A) Basal cell carcinoma B) Occult spina bifida C) Precocious puberty D) Renal anomalies E) Vascular malformations
The correct response is Option B.
The lesion described is a congenital melanocytic nevus (CMN). Basal cell carcinomas are associated with nevus sebaceous. Precocious puberty is seen in congenital adrenal hyperplasia, which is associated with generalized hyperpigmentation most apparent in the areolas and genitalia. Renal anomalies and vascular malformations are not associated with CMN. Abnormalities of the vertebral column including spina bifida are seen with CMN overlying the spine. These lesions are also associated with neurocutaneous melanosis.
2016
A 67-year-old man with a large lentigo maligna on the left cheek comes to the office for closure after undergoing excision. Which of the following steps is most appropriate for the surgeon prior to performing a cervical-facial rotation flap?
A) Await permanent pathology results
B) Confirm negative margins by Mohs micrographic surgery
C) Evaluate the margins clinically with a Wood lamp
D) Perform confocal microscopy
E) Refer the patient for sentinel node biopsy
The correct response is Option A.
Lentigo maligna is a slow-growing lesion with a substantial radial growth pattern before progressing to invasion in most cases. These lesions often occur in the head and neck region of older patients with a history of sun exposure. Clinical occurrence is variable, but many appear as irregular, sometimes extensive, pigmented patches on the face. Staging of these lesions follows the American Joint Committee on Cancer guidelines, and prognosis is based on depth of invasion. Need for sentinel node biopsy is based on staging and is independent of resection size.
Wide local excision of the lesion is the current standard of care, but the surgical margin for successful excision remains controversial. Alternative techniques have been investigated to improve the 8 to 20% recurrence rates associated with standard excision with 5-mm margins. Mohs micrographic surgery shows promise in the treatment of this disease, but there remains difficulty in interpretation of melanocyte proliferation on frozen section, leading to the proposal of modifications of the procedure, including sending the final Mohs margins for rush permanent section evaluation for verification of clear margins, the so-called “slow Mohs.”
Clinical evaluation of margins with Wood lamp may be useful in evaluating the clinical extent of the lesion but is not adequate for determination of surgical margins. Confocal microscopy is a new technique that allows examination of melanocytes without biopsy. This modality may be useful in diagnosis of lentigo maligna, but availability is currently limited and requires training in interpretation of images.
2014
An 89-year-old man comes to the office because of a 2-year history of a pigmented lesion of the left cheek. The patient has an extensive history of sun exposure but no history of skin malignancy. On examination, the lesion is flat and light brown with irregular borders, but has no nodularity or ulceration. Examination of a specimen obtained on punch biopsy shows lentigo maligna. Which of the following is the most appropriate treatment?
A) Cryotherapy with liquid nitrogen B) External beam radiation C) Laser ablation D) Resection with 1-cm margins E) Topical treatment with imiquimod
The correct response is Option D.
Lentigo maligna is melanoma in situ that primarily occurs in elderly patients with a history of extensive sun exposure. It represents 4 to 15% of all melanomas and is slow-growing in a radial phase, but can progress to lentigo maligna melanoma with invasion and metastatic potential.
Surgical resection remains the standard of care for treatment of lentigo maligna. In 1992, the National Institutes of Health Consensus Conference on Melanoma recommended a 5-mm margin for excision of lentigo maligna. However, the use of 5-mm margins has been associated with recurrence rates of 8 to 20%. In 2008, the National Cancer Comprehensive Network released guidelines indicating that 5-mm margins may be inadequate for treatment of lentigo maligna. The use of a staged excision technique has shown that 10-mm margins or greater were required in a majority of patients and resulted in low (1.7%) recurrence rates at 2 years.
Nonsurgical modalities have been investigated in the treatment of this lesion, as they tend to occur in elderly patients who may not be surgical candidates. Nonsurgical treatments are associated with recurrence rates of 20 to 100%, with laser ablation associated with the highest recurrence rates. Topical imiquimod has shown promise, but data is limited, and long-term cure rates are unknown at this point.
2013
An 88-year-old woman comes to the office because of the 2-cm pigmented lesion on the vertex of the scalp shown. There is no evidence of cervical or suboccipital lymphadenopathy. Examination of a specimen obtained on punch biopsy shows a Breslow thickness of 2.1 mm, Clark Level IV, two mitotic figures per high-power field, and no evidence of ulceration. Which of the following is the most appropriate management?
A) Excision with 1-cm margins and bilateral cervical lymphadenectomy
B) Excision with 2-cm margins and delayed sentinel lymph node biopsy
C) Excision with 3-cm margins and bilateral cervical lymphadenectomy
D) Preoperative lymphoscintigraphy, excision with 1-cm margins, and immediate sentinel lymph node biopsy
E) Preoperative lymphoscintigraphy, excision with 2-cm margins, and immediate sentinel lymph node biopsy
The correct response is Option E.
In the patient described with an intermediate thickness tumor (1–4 mm) and clinically negative neck, the most appropriate treatment is wide excision with 2-cm margins (shown) and a concurrent sentinel lymph node biopsy. The defect may be reconstructed with a local flap or skin graft depending on patient and surgeon preference. In Stage I and II melanomas (localized disease T1-4, and no evidence of regional lymphadenopathy, N0), Breslow tumor thickness is the most important predictor of local recurrence, regional/distant metastases, and overall survival.
Current recommended excisional margins are 0.5 to 1.0 cm for melanoma in situ/lentigo maligna. For invasive lesions less than 1 mm thick, a 1-cm margin is adequate. Lesions with Breslow thickness of 1 to 2 mm should be resected with a 1- to 2-cm margin, using closer to 2 cm when the anatomical area is more forgiving (scalp/trunk), the thickness approaches 2 mm, or the lesion displays more aggressive histopathologic features, such as ulceration, lymphovascular invasion, tumor regression, or a mitotic index greater than one figure per high-power field. Lesions between 2 to 4 mm are adequately treated with 2-cm margins. Balch, et al., have shown that 2-cm margins are safe for lesions of intermediate thickness with equivalent survival rates, less use of skin grafting, shorter hospital stays, and lower medical costs when compared with more aggressive peripheral margins. When possible, 3-cm margins should be used for tumors greater than 4 mm thick because of their high local recurrence rate (greater than 20%).
Patients with intermediate-thickness melanomas have a 20 to 25% chance of microscopic regional disease. Before the advent of sentinel lymph node biopsy, elective lymphadenectomy (ELD) was advocated for patients with intermediate-thickness melanoma because of a significant improvement in overall survival at 10 years. The primary disadvantage of routine ELD, however, was that approximately 75 to 80% of patients underwent an unnecessary procedure.
The status of the sentinel lymph node is a powerful predictor of survival in melanoma because it identifies:
(1) those patients with a relatively favorable prognosis requiring no further therapy; and
(2) high-risk patients who might benefit from additional surgery (completion lymphadenectomy) and interferon.
Current indications for sentinel lymph node biopsy include all of the following: male patients with truncal melanoma less than 0.76 mm thick (9% incidence of nodal metastasis); all patients with melanoma thickness 0.76 to 1.0 mm (5% incidence of nodal metastasis); male patients with “thin” melanomas with aggressive features (Clark Level III or greater, ulcerated, evidence of regression, or axial location; these patients have a 10% risk of metastasis); and all melanomas greater than 1 mm in thickness.
In the scenario described, 1-cm margins would be too narrow. A 3-cm margin is excessive for the lesion described. As noted, elective lymphadenectomy has been replaced with sentinel lymph node biopsy in a clinically negative neck. Finally, sentinel lymph node biopsy should be performed at the time of the primary tumor resection if possible due to variations in the lymphatic drainage that may occur after wide excision, skin grafting, or flap closure.
2013
A 40-year-old, right-hand-dominant man comes to the office because of a 2-mm pigmented lesion beneath the thumbnail of the left hand. He says that he first noticed the lesion within the last week. The patient recalls no trauma to the thumb. He has no other fingernails or toenails with similar streaking. Biopsy of a subungual lesion is most appropriate after which of the following periods of time has passed without change?
A) 0 to 3 Weeks B) 4 to 6 Weeks C) 7 to 9 Weeks D) 10 to 12 Weeks E) 13 to 15 Weeks
The correct response is Option B.
The prognosis for a subungual melanoma is worse than that of cutaneous melanoma. Often, there is a delay in the diagnosis of subungual melanomas; in practice, it is better to be highly suspicious of any pigmented lesion beneath the nail and perform a biopsy. According to recent research, the 5-year survival rate for a patient with a subungual melanoma ranges from 28 to 30%. The 10-year survival rate drops to 0 to 13%. Clearly, this is a devastating disease, and over-vigilance regarding diagnosis is recommended. The current recommendation is to perform a biopsy of any subungual lesion after 4 to 6 weeks without significant change.
2013
A healthy 8-year-old girl is brought to the office because of a 15-cm congenital nevus of the buttock and thigh. Which of the following is the most appropriate recommendation to the parents for management?
A ) Alexandrite laser treatment B ) Punch biopsy C ) Serial excision starting at age 21 years D ) Tissue expansion and excision E ) Observation for 3 to 6 months
The correct response is Option D.
While the overall lifetime risk of congenital nevomelanocytic lesions is estimated in the 5 to 12% range, giant nevi tend to transform earlier. Some studies suggest that 50% of the malignancies that do develop in large nevi do so by age 3 years, and 70% occur by puberty. Giant nevi are classified as lesions over 20 cm in adults, or lesions in children that are estimated to reach 20 cm by full growth (9 cm on the head, 6 cm on the body). Patients with giant congenital nevi are estimated to have a 51% increased risk of developing melanoma. Another study showed a 5-year malignant melanoma transformation rate of 5.1%.
Given this propensity for malignant transformation, many authors advocate early aggressive treatment of giant nevi, starting at age 6 months. Serial excision, skin grafting, cultured epidermal autografts, and dermal regeneration templates (Integra) have all been described as treatments. In older patients, rotation and free flaps can be incorporated as needed.
Alexandrite lasers have not been advocated for nevi. Studies of ruby and carbon dioxide lasers have mixed results, some showing adequate lesion destruction and cosmesis, others with high rates of hypertrophic scarring.
Observation may be appropriate for smaller congenital nevi, though in this patient, at this age, the melanoma risk is sufficient to warrant intervention. Over 3 to 6 months, one would not expect clinically significant changes. Indeed, many would have urged earlier treatment. Waiting until age 21 years would also be inadvisable.
Punch biopsy is useful for surveillance of smaller lesions, though it may not be representative of a large lesion, and could possibly yield false-negative results.
2012
A 45-year-old woman comes to the office with a history of a 4.1-mm irregular black lesion of the left leg. Excisional biopsy was performed by her primary physician with a 1-mm margin. The pathology result reveals a 1.8-mm thick ulcerated malignant melanoma. A wide local excision is planned. Which of the following is the most appropriate excision margin for this lesion?
A ) 0.5-cm margin B ) 1-cm margin C ) 2-cm margin D ) 3-cm margin E ) 5-cm margin
The correct response is Option C.
The diameter of the melanoma described is not taken into account for the wide local excision that is to be performed. Wide local excision surgical margins are determined by the thickness of the tumor, not the diameter.
An in situ melanoma would require a 0.5-cm margin.
Melanomas with a depth of less than 1 mm (thin) require a 1-cm margin.
Lesions between 1 and 4 mm (intermediate thickness) require a 2-cm margin.
If the depth is greater than 4 mm (thick), a 2- to 3-cm margin is necessary. Intermediate melanomas (those of a 1- to 4-mm depth) had previously required a 4-cm margin of resection.
In a landmark article in 1993, Balch, et al. recommended a 2-cm margin for intermediate-depth melanomas. Another landmark article in 1998 by Heaton, et al. advocated surgical margins of 2 cm for patients with thick melanoma.
2012
A 60-year-old man comes to the office because of a 2-cm pigmented lesion on the right lower back (shown) that has enlarged progressively for 3 years. No lymph nodes are palpable. Examination of a specimen obtained on punch biopsy shows a Clark Level IV malignant melanoma with a Breslow thickness of 1.2 mm and ulceration. Which of the following is the most appropriate management?
A) Excision with 2-cm margins
B) Preoperative lymphoscintigraphy, sentinel lymph node biopsy, and excision with 1-cm margins
C) Preoperative lymphoscintigraphy, sentinel lymph node biopsy, and excision with 2-cm margins
D) Excision with 1-cm margins, followed by lymphoscintigraphy and sentinel lymph node biopsy at a later date
E) Excision with 3-cm margins, split-thickness skin grafting, and right axillary lymph node dissection
The correct response is Option C.
A melanoma 1.2 mm in thickness on the lower back would best be excised with 2-cm margins and a concurrent sentinel lymph node biopsy. Although a few studies cite the adequacy of a 1-cm margin for tumors less than 2 mm in thickness, a punch biopsy was performed in the scenario described, and the final pathology of the complete lesion could show a thicker lesion. In a location where there is sufficient tissue, a 2-cm margin is more appropriate for a lesion that is over 1 mm in thickness. Most authors cite resection margins of 5 mm for melanoma in situ, 1 cm for melanoma less than 0.8 mm, and 2 cm for melanoma between 0.8 and 4 mm.
Patients with intermediate thickness lesions of 0.8 mm to 4 mm have a 20 to 25% incidence of microscopic regional disease. Sentinel lymphadenectomy serves to identify patients at high risk who may be candidates for adjuvant treatment. At this time, sentinel lymph node biopsy is a diagnostic, but not yet proven, therapeutic procedure.
In patients with melanomas greater than or equal to 1 mm in thickness and no clinical evidence of regional lymph node metastases, lymphoscintigraphy is performed preoperatively to define the lymphatic drainage and demonstrate sentinel lymph node location. Sentinel lymphadenectomy is performed most accurately at the time of wide and deep excision of the primary lesion. Later, sentinel lymph node localization may be impaired if the primary lesion has been excised deeply, as the drainage patterns may have been altered by the previous procedure.
It is imperative to obtain preoperative lymphoscintigraphy in areas with a high likelihood of aberrant drainage patterns. In the trunk, unpredictable drainage patterns can occur in 20 to 35% of cases.
2011
A 65-year-old Caucasian man comes to the office because of a dark, pigmented lesion on the thumb that he first noticed 3 months ago. There is no history of trauma to the digit. Physical examination shows a variegated lesion with asymmetrical borders in the germinal matrix of the nail bed of the right thumb. Which of the following is the most appropriate first step in management?
A ) Amputation to next joint B ) Radiation therapy C ) Shave biopsy D ) Wide excision E ) Observation
The correct response is Option C.
This pigmented lesion in the patient described could be a post-traumatic subungual hematoma, benign nevus, or subungual melanoma. Benign streaks in the nail plate (melanonychia striata longitudinalis) are extremely common in African American patients and often occur spontaneously with advancing age. Similar streaking of pigment in the nail plate may reflect the presence of a benign subungual nevus of the germinal matrix. Broader streaks of variegated color and streaks with cubical pigmentation should raise suspicion of a subungual melanoma. Evaluation of a suspiciously pigmented lesion in the nail bed should commence with a shave biopsy of the lesion. A core biopsy of the germinal matrix could produce a nail bed and plate abnormality. Furthermore, there is no need for a core biopsy to determine the depth of the lesion, as the histology and staging of the nail bed are different from the skin. Wide excision or amputation is not warranted until an attempt at diagnosis has been completed. The lesion has been present for 3 months and has not grown out to the sterile matrix; because the patient says there has been no previous trauma, further observation would be inappropriate. After an injury, the nail plate and corresponding matrix grow to tip by 3 to 4 months. Radiation therapy is not appropriate without a diagnosis.
Melanocytic hyperplasia without atypia is considered benign and can be observed. The presence of atypia or melanoma in situ requires complete excision with clear margins. The wound is closed with a full- or split-thickness nail bed graft. Acral-lentiginous melanoma is found beneath the nail, on the palm of the hand, or on the sole of the foot. These lesions represent approximately 3% of all cutaneous melanomas. The prognosis for subungual melanomas is worse than for other cutaneous melanomas, probably because of delay in diagnosis. When symptoms occur, 25 to 30% of patients have metastases. Treatment of subungual hand melanomas consists of amputation through the joint, just proximal to the lesion. Volar flaps are used for the closure of the defect. For lesions of the thumb, deepening the first space with local z-plasty is recommended to improve function.
2010
A 67-year-old woman presents with a 7-mm, irregular, asymmetrical, heterogeneous brown macule that has been enlarging for the past 2 months. An excisional biopsy with 2-mm margins shows melanoma. After tumor thickness, which of the following pathologic features is most indicative of her prognosis?
A) Clark level B) Macule diameter C) Mitotic rate D) Morpheaform features E) Ulceration
The correct response is Option E.
This lesion has all of the clinical features suggestive of melanoma: asymmery, irregular border, heterogeneous color, diameter greater than 6 mm, and evolution. After thickness, ulceration is the most important prognostic indicator for melanoma, and has become an important component of T staging. The prior AJCC staging system did consider mitotic rate but recent evidence has shown that ulceration is a more important prognostic indicator. Mitotic rate is no longer a factor in determining T stage, whereas ulceration is. Clark level and lesion diameter are not independent predictors of outcome for melanoma. Morpheaform features are associated with poorer outcomes in basal cell carcinoma.
2019
A 55-year-old Caucasian man comes to the office for evaluation of a pigmented streak of the left thumb and index fingernails. Medical history includes a minor crush injury to the thumb one year ago that required no treatment. Examination shows a 4-mm-wide pigmented streak in both digits that extends from the eponychial fold to the tip of the sterile matrix. The patient reports that the pigmented areas have become darker over time. Which of the following clinical features is most consistent with a benign lesion?
A) Age greater than 50 years B) Change in color over time C) Involvement of more than one digit D) Pigmentation involving the periungual skin E) Width greater than 3 mm
The correct response is Option C.
Subungual melanoma is a relatively rare melanoma subtype accounting for 0.7 to 3.5% of all melanomas. Because of the location, appearance, and unique anatomy of the nail unit, subungual melanomas are often diagnosed late in more advanced stages than typical cutaneous melanoma. There is disagreement as to whether subungual melanomas behave more aggressively than cutaneous melanomas of comparable depth. In addition, it can be difficult to distinguish subungual melanomas from benign melanonychia.
Characteristics that are concerning for subungual melanoma are: age 50 to 70, longitudinal band greater than 3 mm or irregular border, change of lesion size or coloration, extension onto periungual skin (Hutchinson sign), personal or family history of melanoma, and single finger involvement.
Benign melanonychia is more common in dark-skinned patients. The differential diagnosis of subungual pigmentation includes subungual hematoma, onychomycosis, and Addison disease among others.
In this case, multiple digit involvement is the clue that the lesions are benign. All other characteristics could be consistent with malignant melanoma. If there is concern for subungual melanoma, a full-thickness biopsy of the pigmented area should be performed.
2019
