Integument/Dermatology Flashcards
A 61-year-old male farmer presents to your clinic because he is concerned about a skin lesion on his face. The lesion is shown in the accompanying photograph. Which one of the following is the most likely diagnosis?
A. Keratoacanthoma.
B. Basal cell carcinoma.
C. Implantation dermoid cyst.
D. Amelanotic malignant melanoma.
E. Squamous cell carcinoma.
B. Basal cell carcinoma.
The appearance of the lesion is consistent with nodular basal cell carcinoma (BCC). BCC is the most common skin cancer. Unlike squamous cell carcinoma (SCC), BCC can be seen in non-photoexposed areas as well. Nodular BCC is the most common subtype. The pearly appearance, shiny surface and telangiectasis are characteristic features. Additionally, the lesion in the photograph has undergone ulceration at parts.
Option A: Keratoacanthoma has the central crater filled with necrotic tissue, which is not seen here.
Option C: Implantation dermoid cysts are firm subdermal cystic nodules that often occur following a penetrating trauma. The fingertips of mechanics are the most common site for such lesions.
Option D: Amelanotic melanoma can resemble a nodular BCC; although it will lack the pearly appearance of BCC, which can be noted in this photograph.
Option E: Squamous cell carcinoma does not fit the clinical picture. It usually presents with an ulcerating plaque.
A 43-year-old farmer from Queensland presents with a pigmented lesion on his upper chest, shown in the accompanying photograph. The lesion appeared 4 months ago, but recently has enlarged. The lesion has been itchy and oozing and painful for the past 3 weeks. Which one of the following is the most likely diagnosis?
A. Malignant melanoma.
B. Keratoacanthoma.
C. Basal cell carcinoma.
D. Blue nevus.
E. Benign pigmentation.
A. Malignant Melanoma.
Although the lesion shown in the photograph may be mistakenly considered as a pigmented nodular basal cell carcinoma, a more careful inspection of the lesion indicating pigmentation of different colors as well as the history of the rapid progression over 4 months suggests malignant melanoma (nodular type) as the most likely diagnosis.
Option B: Keratoacanthoma has the typical crater which is absent here. The crater often has keratin or dead skin cells inside.
Option C: Pigmentation and color variegation of this lesion favors melanoma rather than basal cell carcinoma. Moreover, the rapid progression and evolution of symptoms such as itching and tenderness are more commonly seen in melanoma.
Option D and E: Clinical presentation and the history (rapid course of progression and evolving of size and symptoms) definitely exclude blue nevus and benign pigmentation as the likely diagnoses.
On a routine health examination of a 72-year-old man, you notice lesions depicted in the following photograph on his back. Which one of the following could be the most likely diagnosis?
A. Superficial spreading melanoma.
B. Mycosis fungoides.
C. Hutchinson melanotic freckles.
D. Seborrheic keratosis.
E. Solar keratosis.
D. Seborrheic keratosis.
The appearance of the lesions are suggestive of seborrheic keratosis. Characteristic features include variegated pigmentation from black to tan, the verrucous greasy surface and occurrence in crops.
Seborrheic keratoses are well-defined benign lesions which are often pigmented and can occur on the head, neck, trunk and limbs and areas not always significantly exposed to sunlight. Although the etiology is unknown, sun exposure may play a role.
They usually start to appear in the third decade of life and increase in number as the age advances. Seborrheic keratoses are the most common benign pigmented tumors in those aged 50 years and over.
Seborrheic keratoses are typically round plaques with adherent greasy scale. They seem to be stuck on the skin. Their color may vary from black to tan. The surface appears velvety to verrucous. Sometimes they are so verrucous that may be mistaken with warts, particularly if not heavily pigmented. Sometimes there are surface cracks and horn cysts.
Some seborrheic keratoses are flat. Flat lesions, particularly those of the face and the limbs, may be difficult to be distinguished from melanoma or lentigo maligna. This is even more true if the lesions are inflamed and consequently, enlarged and itchy with tendency to bleed.
Option A: Superficial spreading melanoma is another likely diagnosis, especially if the lesions were more superficial. The large number of the lesions, smooth margins and the greasy warty look of the lesion in the center make seborrheic keratosis a more likely diagnosis. Biopsy and histological studies are required if the diagnosis is in doubt.
Option B: Mycosis fungoides is a misnomer describing a rare involvement of the skin with lymphoma. The appearance would be irregular eczematous dermatitis progressing to form plaques.
Option C: Hutchinson melanotic freckles have more irregular borders and are more flat than the lesions depicted. Furthermore, Hutchinson melanotic freckle more commonly tends to be solitary and on sun-exposed areas.
Option E: Solar keratoses are firm, hyperkeratinous plaques of 2 to 10mm in size seen in sun-exposed areas e.g. dorsum of hands.
A 41-year-old farmer has presented with a lesion on his right sole. The lesion appeared 4 months ago and has progressively enlarged since then. The lesion is shown in the accompanying photograph. Which one of the following could be the most likely diagnosis?
A. Neuropathic ulcer.
B. Malignant melanoma.
C. Simple nevus.
D. Pigmentation from heat.
E. Squamous cell carcinoma.
B. Malignant Melanoma.
The size and color of the lesion, the irregularity, and the rapid progression are highly suggestive of malignant melanoma.
Option A: Neuropathic ulcers occur over pressure points of areas with impaired sensation due to conditions such as diabetes mellitus (the most common cause), syphilis, leprosy, and other neuropathies. They present a completely different picture.
Option C: The rapid progression, size, and irregularity are consistent with melanoma rather than simple nevus as a diagnosis. A simple nevus usually has regular borders, is often unicolor, and does not spread so fast.
Option D: Pigmentation from heat, also called ‘erythema ab igne’ is tanning of the skin, where it is chronically exposed to heat.
Option E: Cutaneous squamous cell carcinoma (SCC) presents with a usually amelanotic skin lesion in sun-exposed areas.
Which one of the following is not correct regarding contact dermatitis?
A. Plants are the most common cause of contact dermatitis.
B. It can be treated with topical steroids.
C. It can be treated with oral steroids.
D. The application of skin moisturizers can assist the healing process.
E. Avoidance of the allergen is essential to the prevention of further flare-ups.
A. Plants are the most common cause of contact dermatitis.
Allergic contact dermatitis is a type 4 or delayed hypersensitivity reaction and occurs 48–72 hours after exposure to the allergen. The mechanism involves CD4+ T-lymphocytes and the release of cytokines that activate the immune system and cause dermatitis.
Contact allergy occurs predominantly from an allergen on the skin rather than from internal sources or food. Of note, a patient might have been in contact with the allergen for years without it causing dermatitis. Even small quantities of an allergen can induce dermatitis.
Allergic contact dermatitis is especially common in metal workers, hairdressers, beauticians, healthcare workers, cleaners, painters, and florists. Patients with impaired barrier function are more prone to contact dermatitis.
Allergic contact dermatitis develops hours after contact with the responsible material and settles down over some days provided the skin is no longer in contact with the allergen. The condition is often limited to the site of contact with the allergen, but it may extend outside the contact area or become generalized. Transmission from the fingers can lead to dermatitis on the eyelids and genitals. Dermatitis is unlikely to be due to a specific allergen if the area of skin most in.
Some typical examples of allergic contact dermatitis include:
* Eczema in the skin in contact with jewelry items, due to contact allergy to nickel
* Reactions to fragrances in perfumes and household items
* Eczema under adhesive plaster, due to contact allergy to rosin
* Swelling and blistering of face and neck in reaction to permanent hair dye, due to allergy to paraphenylenediamine
* Hand dermatitis caused by rubber gloves
* Itchy red face due to contact with methylisothiazolinone, a preservative in wash-off hair products and baby wipes
* Fingertip dermatitis due to acrylates used in hair extensions and nail cosmetics.
* Reactions after dental implants containing acrylates
* Localized blistering at the site of topical medications
* Swelling and blistering on exposed sites (e.g., face and hands) due to contact with plants such as poison ivy
Therefore, prevention of further contact with the allergen is the mainstay of the treatment. A skin patch test may be required to find the culprit. Active lesions are often treated with topical steroids (option B). More severe cases may necessitate a short course of oral steroids (option C).
Depending on the severity and the clinical course, other treatment options can include phototherapy/photochemotherapy, immune suppressants such as azathioprine or ciclosporin, or immune system modulators tacrolimus ointment.
The application of skin moisturizers (option D) can promote general skin health conditions, alleviate the symptoms, and accelerate the healing process.
Although plants could result in contact dermatitis, they are not the most common cause of contact dermatitis. Nickel and other metals/ chemicals are the most common cause of contact dermatitis.
A 32-year-old woman presents to your clinic for a skin checkup. On examination, she is found to have a skin lesion on her upper back. The lesion is highly suspected of being melanoma. An excisional biopsy is performed with 2 mm margins and the specimen is sent to a laboratory for histopathological studies. The result is a melanoma of 2.5 mm in depth. The margins, however, are clear. Which one of the following would be the next best step in management?
A. A wider excision.
B. Radiation therapy.
C. Sentinel node biopsy.
D. CT scan of the head.
E. Chemotherapy.
A. A wider excision.
Every lesion suspected of being melanoma should be surgically excised with 2 mm margins both as the initial management and the most appropriate step in diagnosis. Further management is then guided by the results of the biopsy. If the lesion is proved to be melanoma, a wider excision is needed. The margins of the second excision depend on the reported depth of melanoma, and is according to the following table.
For melanomas greater than 1mm in depth, a sentinel node biopsy is recommended during the second excision to assess the potential metastasis to the subcutaneous tissue and lymph nodes.
Which one of the following is the most important prognostic factor in basal cell carcinoma?
A. Depth of the lesion.
B. The colour of the lesion.
C. Residual cancer cells in the margins of the excised lesion.
D. The width of the lesion.
E. The site of the lesion.
C. Residual cancer cells in the margins of the excised lesion.
Generally, the prognosis for patients with BCC is excellent, with a 100% survival rate for cases that have not spread to other sites. Typically, basal cell tumors enlarge slowly and relentlessly and tend to be locally destructive. Periorbital tumors can invade the orbit, leading to blindness, if diagnosis and treatment are delayed. BCC arising in the medial canthus tends to be deep and invasive and more difficult to manage; this type of BCC can result in perineural extension and loss of nerve function.
Although BCC is a malignant tumor, it rarely metastasizes. The incidence of metastatic BCC is estimated to be less than 0.1%. The most common sites of metastasis are the lymph nodes, lungs, and bones.
Treatment of BCC is curative in more than 95% of cases; however, BCC may recur, especially in the first year, or develop in new sites. The prognosis of BCC is, therefore, mostly based on the likelihood of recurrence.
There are several prognostic factors affecting the chance of recurrence of a BCC. Of which, the clinical location, the architectural pattern and excision margins are the most important factors. Of these three, most reports consider the presence or absence of tumor cells in the excision margins as the most significant prognostic factor regarding recurrence.
Option A and D: Although the width and depth of tumors are important, as long as they can be excised with tumor-free margins the prognosis is good with recurrence being less likely.
Option C: Although different BCCs can vary in color and some with specific morphological or histological characteristics more likely to recur, color alone is not of great significance in determining the prognosis.
Option E: The site of the lesion is important due to the fact that lesions in specific areas are less likely to be excised with tumor-free margins. Some of these areas are nose, eyelids, temples, pre- and post-auricular regions and lower legs.
TOPIC REVIEW
The following parameters affect, to different extends, the outcome and prognosis of BCC:
* Recurrent tumors (poorer prognosis)
* Multiple tumors (poorer prognosis)
* Size and depth of invasion (stage)
* Morphemic, infiltrating and micronodular (poorer prognosis) Morphological and histological subtype
* Treatment modality (Mohs surgery has been associated with best prognosis)
* Incomplete excision (probably the poorest prognosis)
* Perineural spread
* Nevoid basal cell carcinoma syndrome (poorer prognosis)
* Special sites (poorer prognosis):
Nose
Eyelids
Temple
Pre- and post-auricular
Lower legs
A 59-year-old farmer presents to your clinic with a lesion on his upper chest. The lesion has appeared and progressively enlarged in the past 2 months. Examination establishes a diagnosis keratoacanthoma with high certainty. Keratoacanthoma is more likely to be confused with which one of the following?
A. Basal cell carcinoma.
B. Squamous cell carcinoma.
C. Pyogenic granuloma.
D. Seborrheic keratosis.
E. Granuloma fissuratum.
B. Squamous cell carcinoma.
Keratoacanthoma (KA) is a rapidly growing tumor of keratinocytes. They are almost exclusively seen in sun-exposed areas. The characteristic feature is the crater; the central part of the lesion is necrotic, giving the lesion the appearance of a volcano.
KAs are now considered a low-risk variant of squamous cell carcinoma (SCC). The major diagnostic problem is confusion with SCC, especailly for KAs of the nose and the lips. Interestingly, sometimes KAs cannot be told apart from SCCs based on cytological studies and the whole specimen is needed for differentiation.
Option A: An ulcerated nodular BCC may resemble KA, but SCC remains the most confusing differential diagnosis.
Option C and D: Pyogenic granuloma and seborrheic keratosis are very unlikely to be confused with KA.
Option E: Granuloma fissuratum is a firm red fissured fibrotic granuloma found in the gums and buccal mucosa. It is usually caused by ill-fitting dentures.
A 32-year-old female patient presents to your practice complaining of a skin lesion on the ventral aspect of her right forearm, which has developed during the past 6 weeks. The lesion is shown in the accompanying photograph. She had a successful renal transplant last year. Which one of the following would be the most appropriate treatment?
A. No active treatment is needed,as it resolves spontaneously.
B. Surgical removal of the lesion.
C. Radiotherapy.
D. Topical podophyllin.
E. Removal with liquid nitrogen.
B. Surgical removal of the lesion.
The lesion in the photograph is a domed nodule with a necrotic plug in the center. The appearance is characteristic of Keratoacanthoma (KA). KAs are keratinizing skin tumors which grow more rapidly (6-8 weeks) compared with basal cell carcinoma, squamous cell carcinoma and melanoma. They are usually seen as a solitary nodule in sun-exposed areas. It often develops later in life with a predilection for women.
If the lesion is left untreated, spontaneous healing and resolution may occur within 3 to 6 months; however, at instances it may continue to grow or even metastasize.
Since KA is clinically indistinguishable from malignant lesions, especially squamous cell carcinoma, the preferred management would be the same as for squamous cell carcinoma which is elliptical surgical excision with margins of 3-5mm (the same that would be done for squamous cell carcinoma of the skin).
KAs share features such as infiltration and cytological atypia with SCCs; hence they are considered to be a variant of SCC called SCC-KA type.
Although a shave biopsy may be used for diagnosis, it is not an adequate final treatment and complete excision should eventually follow.
The need for complete surgical removal is even more in patients who have undergone organ transplantation, because these patients are on immunosuppressive medications drugs; therefore, the lesion is more likely to be malignant. Even if the case is KA, spontaneous resolution is far less likely in the presence of immunosuppression.
A 36-year-old woman presents to your clinic concerned about a lesion on her right shin. The lesion appeared several days after the site was stung by a bee. On examination, there is a 0.6mm nodule on the lateral aspect of the right shin as illustrated in the photograph. It is not tender to touch. Which one of the following could be the most likely diagnosis?
A. Basal cell carcinoma.
B. Squamous cell carcinoma.
C. Dermatofibroma.
D. Molluscum contagiosum.
E. Pyogenic granuloma.
C. Dermatofibroma.
The appearance, history, and exam findings are suggestive of dermatofibroma as the most consistent diagnosis.
Dermatofibroma, also called sclerosing hemangioma or histiocytoma, is a common pigmented nodule in the dermis due to the proliferation of fibroblasts, usually following minor trauma.
Dermatofibroma is more commonly seen in women on the lower leg. The lesion is a button-like nodule that is firm and well-circumscribed. The size may vary from 0.5 to 1cm. It can be pink, brown, tan, gray, or violaceous. The nodule is freely mobile over the deeper structures. The characteristic feature on examination is a dimpling of the nodule when it is pinched laterally (dimple sign). The lesion is often asymptomatic but may be itchy or tender.
Other options have different characteristic features.
A 47-year-old man presents because of a lesion on the back of his right shoulder. The lesion is illustrated in the following photograph. Which one of the following is the most appropriate advice?
A. The lesion should be excised, as it is malignant and can extend locally, but not through lymphnodes.
B. The lesion is benign and does not need to be excised.
C. The lesion is benign, but should be excised because it can become malignant.
D. The lesion is benign, but should be excised because it can become infected.
E. The lesion is malignant and should be excised because it can metastasize through adjacent lymph nodes.
D. The lesion is benign, but should be excised because it can become infected.
The photograph shows a well-circumscribed lesion, which appears to arise from within the epidermis. It also has a punctum in the center. These features are characteristic of an epidermoid (sebaceous) cyst.
Epidermoid cysts originate from the dermis and are attached to the skin. Since they are related to the pilosebaceous follicle, they can occur in any hair-bearing region such as the scalp or scrotum.
Of note, the yellow cheesy material within the cyst is desquamated keratin, not sebum.
Epidermoid cysts are benign and do not progress to malignancy; however, it is recommended that they be removed, as superinfection may lead to suppuration and abscess formation.
A 6-year-old boy is brought to you by his mother because she is concerned about skin lesions on the boy’s back and trunk. The lesions have started to appear and increase in number for the past week. The rash over his back is shown in the accompanying photograph. On examination, the child is well and healthy with no other abnormal findings. Which one of the following is the most likely diagnosis?
A. Varicella zoster.
B. Impetigo.
C. Molluscum contagiosum.
D. Herpes simplex.
E. Papilloma virus (warts).
C. Molluscum contagiosum.
The lesions in the photograph are pearly dome-shaped papules with central umbilication characteristic of molluscum contagiosum as the most likely diagnosis. Molluscum contagiosum is a common viral infection of childhood caused by molluscipoxvirus a member of the poxvirus family.
The infection presents with firm, smooth, spherical papules that are pearly white and have a central dimple (umbilicus). Most papules range from 1 to 3 mm; however, lesions of up to 1-2 cm have been reported mostly due to coalescing smaller lesions.
Lesions can develop anywhere, but flexures and areas of friction are more frequently involved. Lesions may also occur in the anogenital area and are not usually associated with sexual abuse of the child. Involvement of the eyelid margins may lead to chronic conjunctivitis.
Molluscum contagiosum has a benign course and nature. Most patients experience the spontaneous resolution of the lesions within 3 to 6 months, but on occasion, it may take up to 3 years.
Option A: Varicella zoster infection in children (chickenpox) presents with blisters at different stages (intact, ruptured, crusted, or sometimes infected) which are often itchy. The eruption usually follows prodromal symptoms such as malaise and fever. None of the history and physical examination features is consistent with varicella zoster infection.
Option B: Impetigo is a superficial skin infection presenting with lesions often with honey-colored crusting.
Option D: Herpes simplex presents with painful vesicles that may become unroofed to produce a raw appearance.
Option E: Papillomavirus infection (wart) presents a completely different picture. Often it is cauliflower-like with a rough surface.
There are a number of skin lesions which are related to cumulative sun-exposure. Which one of the following is most likely to be caused by chronic sun exposure?
A. Actinic (solar) keratosis.
B. Junctional nevus.
C. Seborrheic keratosis.
D. Tinea versicolor.
E. Keratoacanthoma.
A. Actinic (solar) keratosis.
Actinic keratosis and Bowen’s disease are seen frequently in light-skinned individuals, who have had significant sun-exposure. They are precancerous lesions for squamous cell carcinoma.
Option B: Junctional nevus is not associated with sun-exposure.
Option C: Seborrheic keratosis does not seem to have strong association with sun-exposure because it frequently appears in areas not exposed to and affected by the sunlight.
Option D: Tinea versicolor is a skin infection caused by Malassezia furfur and is aggravated by heat and damp, but not related to sun exposure.
Option E: Keratoacanthoma is a rather benign tumor arising from pilocebaceous glands, mostly in sun-exposed areas such as face. The association with sun-exposure is not as significant compared with actinic keratosis or Bowen’s disease.
A 50-year old farmer presents to your practice with a dark mole on his left cheek. The mole has been there for 20 years, but has enlarged and become slightly lumpy and itchy over the past 4 months. Which one of the following would be the most appropriate management option for this patient?
A. Treat the lesion using liquid nitrogen.
B. Ask the patient to return for review in 3 months.
C. Remove the lesion using the laser.
D. Use topical imiquimod for 6 weeks.
E. Excisional biopsy of the lesion for histopathology.
E. Excisional biopsy of the lesion for histopathology.
A changing mole, a mole with an irregular border, bleeding, itching, or color variegation is melanoma until proven otherwise. When melanoma is suspected, the next best step is an excisional biopsy of the lesion with 2 mm margins. Elliptical incisions are made so that reconstruction of the wound is more straightforward. If histopathological results confirm the diagnosis, referral to a plastic surgeon is necessary for a wider excision with margins of 5 mm to 3 cm depending on the depth of the lesion.
NOTE - in GP settings, patients with suspected lesions on sensitive areas such as the head and neck should be referred to a plastic surgeon even for the initial excision. If the referral was an option, it would be the correct answer.
Which one of the following is the most important risk factor for melanoma?
A. Family history of basal cell carcinoma or squamous cell carcinoma of the skin.
B. A cousin with melanoma in family history.
C. Working outdoors since the age of 18.
D. Multiple sunburn since childhood.
E. Presence of solar keratosis.
D. Multiple sunburns in childhood.
The following table classifies risk factors for developing melanoma in a descending order are as follows.
Among the given options multiple sunburns in childhood predispose to the most significant risk (it is associated with only slightly elevated risk factor, yet the greatest among other options).
Option A: A family history of non-melanoma skin cancers (NMSC) is an important risk factor for NMSC but not for melanoma; however, personal history of NMSC is a significant risk factor for melanoma.
Option B: Family history of melanoma is not that significant if not in the first-degree relatives (parents, siblings).
Option C: Working outdoors since the age of 18 years is another risk factor, but not as important as multiple sunburns.
Option E: Solar keratosis is a significant risk factor for squamous cell carcinoma, not melanoma.
The mother of a 5-year-old boy, who has recently undergone removal of a melanoma on her back asks you what can play a major role in developing melanoma in her child in the future. Which one of the following options would be your answer to her question?
A. Family history of melanoma.
B. Sunburn.
C. Fair skin.
D. UV exposure.
E. The presence of multiple dysplastic moles.
E. The presence of multiple dysplastic moles.
The following table categorizes the risk factors for developing melanoma in a descending order of significance.
All the given options are potential risk factors for developing melanoma, but the presence of multiple moles (>100 nevi or more than 5 dysplastic nevi) is the most significant risk factor.
Red hair and blue eyes are associated with a highly- and moderately-increased risk of melanoma respectively. Fair complexion is another risk factor, but the degree of association with melanoma depends on the age of the patient. In patients over the age of 45 years, fair skin can be as significant a risk factor as multiple nevi.
UV exposure and sunburns are associated with a slightly increased risk of melanoma. In sun-related melanomas, acute intense and intermittent blistering sunburns, especially on areas of the body that only occasionally receive sun exposure, are the most significant risk factors for the development of sun exposure-induced melanoma. This sun-related risk factor for malignant melanoma differs from squamous or basal cell carcinomas.
NOTE - lentigo malignant melanoma (LMM) is an exception to this rule because it frequently appears on the head and neck of older individuals who have a history of long-term sun exposure; therefore, prolonged sun (UV) exposure is the greatest risk factor for LMM.
Exposure to ultraviolet radiation (UVR) is a critical factor in the development of sun-related melanomas. Ultraviolet A (UVA), wavelength 320-400 nm, and ultraviolet B (UVB), 290-320 nm, potentially are carcinogenic and can attribute to melanoma induction. The suggested mechanisms through which UV exposure can play its role are:
* Suppression of the immune system of the skin
* Induction of melanocyte cell division
* Free radical production
* Damage to melanocyte DNAc
Interestingly, melanoma does not have a direct relationship with the amount of sun exposure because it is more common in white-collar workers than in those who work outdoors. Also, it is more common on the back of men’s and women’s lower legs when there is no significant sun exposure.
On a routine health examination, the lesion shown in the following photograph is found on the inner side of the lower lip of a 37-year-old man. The lesion is painless. Which one of the following is the most likely diagnosis?
A. Sebaceous cyst.
B. Peutz-Jegher’s syndrome.
C. Squamous cell carcinoma of the lip.
D. Mucous cyst.
E. Basal cell carcinoma.
D. Mucous cyst.
The lesion shown has a bluish-glistening color and is dome-shaped. These are characteristics of a benign mucoid cyst. A mucous cyst, also known as a mucocele forms when mucus or saliva escapes into surrounding tissues. A lining of granulation or connective tissue is formed to create a smooth, soft round fluid-filled lump. They most commonly occur on the inner surface of the lower lip (75% of cases) but may also appear on the floor of the mouth or on the gums, buccal mucosa, and tongue. If persistent or bothersome, an incision and evacuation of the cyst are performed.
Option A: Sebaceous cysts are caused by obstruction of a sebaceous gland in hair-bearing skin. It does not occur in the lip.
Option B: Peutz - Jegher’s syndrome is associated with melanocytic spots on the buccal mucosa and in the gastrointestinal tract.
Option C and E: Both squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) of the lip occur at the mucocutaneous junction of the lip. The mucus membrane of the lip is unlikely to be the site an SCC or BCC arises. Moreover, patients with SCC or BCC typically are older.
Which one of the following lesions of squamous epithelium is not premalignant?
A. Solar (actinic) keratosis.
B. Leukoplakia
C. Intradermal nevus.
D. Bowen’s disease.
E. Chronic radiation dermatitis.
C. Intradermal nevus.
Of the given options, the only one not associated with skin cancers is intradermal nevus. Benign melanocytic nevi have three major types, classified according to the position of the melanocytes in relation to epidermal:
* Intradermal nevus: all of the nevus cells are within dermis. This type accounts for a majority of benign congenital nevi.
* Junctional nevus: the nevus cells are located at the junction of the basal epidermal layers and dermis.
* Combined nevus: nevus cells are both intradermal and junctional.
Option A: Solar (actinic) keratosis is usually a raised plaque usually on sun-exposed area of the skin. It is a precursor of SCC.
Option B: Leukoplakia is whitish lesion in the oral cavity and associated with SCC.
Option D: Bowen disease is considered SCC in situ, and is malignant.
Option E: Chronic radiation dermatitis may result in SCC.
Which one of the following skin malignancies is most likely to arise from a burn scar?
A. Basal cell carcinoma.
B. Malignant melanoma.
C. Squamous cell carcinoma.
D. Fibrosarcoma.
E. Sweat gland adenocarcinoma.
C. Squamous cell carcinoma.
The most common skin malignancy arising from a burn scar is squamous cell carcinoma (SCC). Marjolin ulcer is a less common type of SCC of the extremities found on chronic ulcers or burn scars. Marjolin ulcers occur on average approximately 30 years after an injury to the skin that results in a scar or an ulcer (range 10–75 years). Rarely, an acute Marjolin ulcer may develop between 6 weeks and 1 year of injury. It is estimated that around 2% of thermal burns scars turn into Marjolin ulcers.
Marjolin ulcer can affect people of all ages, most commonly between 40 and 60 years of age. Men are 2–3 times more likely be diagnosed with Marjolin ulcer than women. All races and skin types can develop Marjolin ulcers. The most common sites for Marjolin ulcers are the legs and feet. The ulcers can also form on the head and neck.
Other options are malignancies not seen or very rarely seen in areas with a burn scar.
Which one of the following is the most likely diagnosis of the lesion shown in the accompanying photograph?
A. Keratoacanthoma.
B. Basal cell carcinoma.
C. Seborrheic dermatitis.
D. Malignant melanoma.
E. Simple nevus.
D. Malignant Melanoma.
The photograph shows a pigmented lesion on the left side of the nose. With pigmentation, the two most likely diagnoses are simple nevi or malignant melanoma. Early melanomas may be differentiated from benign nevi by the ABCD:
* A - Asymmetry
* B - Border irregularity
* C - Color that tends to be very dark black or blue and variable
* D - Diameter ≥ 6 mm
The lesion is asymmetrical (A) and has irregular borders (B). It shows variegation (variation in colors) (C) and seems to be larger than 6mm; therefore, melanoma seems to be the most likely diagnosis.
Keratoacanthoma, basal cell carcinoma, and seborrhoeic dermatitis present quite differently.
A 52-year-old golfer man presents to your GP clinic with an ulcer on his right pinna. He says the lesion is itchy and easily bleeds on scratching. On examination, deeply sunburned areas around the lesion are noted. The lesion is shown in the accompanying photograph. Which one of the following can be the most likely diagnosis?
A. Basal cell carcinoma.
B. Squamous cell carcinoma.
C. Malignant melanoma.
D. Bowen’s disease.
E. Keratoacanthoma.
B. Squamous cell carcinoma.
The photograph shows a flat amelanotic lesion on the left pinna that has undergone ulceration and is slightly crusted. The appearance of the lesion is consistent with cutaneous squamous cell carcinoma (SCC) as the most likely diagnosis.
The classic presentation of a cutaneous SCC includes a shallow ulcer with heaped-up edges, often covered by a plaque usually in a sun-exposed area. Typical surface changes may include the following:
* Scaling
* Ulceration
* Crusting
* A cutaneous horn
Less commonly, cutaneous SCC presents as a pink cutaneous nodule without overlying surface changes. Regional spread of head and neck cutaneous SCCs, may result in enlarged preauricular, submandibular, or cervical lymph nodes.
NOTE - Although, the appearance of the lesion resembles SCC, it should be noted that at times SCC, keratoacanthoma, BCC, or even amelanotic forms of melanoma may look similar and the definite diagnosis cannot be made unless biopsy and histologic studies are performed. However, because of the classic features of the lesion and also the fact that squamous SCC is the most common skin cancer, SCC would be the most likely diagnosis in this case.
Option A: Although basal cell carcinoma (BCC) of this area is more common than SCC, the characteristic features of BCC, especially in its most common form – nodular, is different.
Option C: Malignant melanoma is often pigmented. This amelanotic lesion is less likely to be melanoma.
Option D: Bowen’s disease (SCC in situ) presents with an asymptomatic well-demarcated erythematous patch or plaque. The presence of symptoms makes Bowen’s disease a less likely yet possible diagnosis. Moreover, ill-defined borders of this lesion is not in favor of Bowen’s disease.
Option E: Keratoacanthoma often has a nodular structure with central crater which is absent here.