Skin Tumors Practice Questions

Q: Which finding best differentiates lymphomatoid papulosis from primary cutaneous CD30+ lymphoma?

Spontaneous resolution. ***Spontaneous resolution*** - Lymphomatoid papulosis (LyP) is characterized by recurrent crops of papules and nodules that **spontaneously regress** within weeks to months, even without treatment. - This feature is the most important clinical differentiator from primary cutaneous anaplastic large cell lymphoma (pcALCL), which often requires **aggressive therapy** and does not spontaneously resolve. *Presence of large cells* - Both LyP and pcALCL are characterized by the presence of **large anaplastic CD30+ lymphocytes** in their histological findings. - Therefore, the presence of large cells alone does not differentiate between the two conditions. *CD30 positivity* - Both LyP and pcALCL are defined by the uniform **expression of CD30** on the neoplastic large cells, typically in >75% of tumor cells. - Thus, CD30 positivity is a shared immunophenotypic feature and not a differentiating factor. *Epidermal involvement* - **Epidermal involvement**, such as **epidermotropism** or **ulceration**, can be seen in both LyP and pcALCL, particularly in advanced or ulcerated lesions. - While it may suggest a more aggressive process, it is not a consistently reliable feature to distinguish between LyP's benign course and pcALCL's malignant nature.

Q: A 30-year-old woman with history of melanoma presents at 10 weeks gestation with a new 6mm asymmetric pigmented lesion on the back. Most appropriate next step is:

Excisional biopsy under local anesthesia. ***Excisional biopsy under local anesthesia*** - A **new, asymmetric pigmented lesion** on a patient with a history of **melanoma** is highly suspicious for recurrence or a new primary melanoma. - An **excisional biopsy** provides the most accurate histopathological diagnosis, including depth of invasion (Breslow thickness), which is crucial for staging and treatment planning, especially in pregnancy, where delaying diagnosis can have serious consequences for both mother and fetus. *Superficial shave biopsy* - A superficial shave biopsy may not provide an adequate sample depth if the lesion is a melanoma, potentially leading to **understaging** and **inappropriate management**. - It increases the risk of needing a **re-biopsy** and potentially delaying definitive treatment. *Monthly monitoring with dermoscopy* - Monitoring would be appropriate for **stable, typical nevi**; however, a *new* lesion with suspicious features in a patient with a history of melanoma warrants immediate investigation. - Delaying diagnosis and treatment of a melanoma in pregnancy can lead to significantly **worse outcomes** for the mother and potentially for the fetus through metastasis. *Defer biopsy until postpartum* - Deferring biopsy of a suspicious lesion in a patient with a history of melanoma is **unsafe** and likely to result in **disease progression** and poorer prognosis. - **Melanoma can metastasize** during pregnancy, and early diagnosis and treatment are critical.

Q: Which procedure is most appropriate for a 0.8cm superficial BCC on the cheek?

Mohs surgery. ***Mohs surgery*** - This procedure is ideal for **BCCs on the face** due to its **tissue-sparing** and **high cure rate** properties. - Its real-time microscopic control ensures complete tumor removal while preserving maximum healthy tissue, which is crucial for cosmetic outcomes on visible areas like the **cheek**. *Curettage and electrodesiccation* - This method is typically used for **smaller, superficial BCCs** on the trunk or extremities, not generally for facial lesions in cosmetically sensitive areas. - It has a **higher recurrence rate** for facial BCCs compared to Mohs surgery due to the lack of margin control. *Cryotherapy* - While effective for some superficial skin lesions, **cryotherapy** can lead to **scarring** and **pigment changes**, which are undesirable on the face. - It also lacks histological confirmation of complete tumor removal, leading to a **higher risk of recurrence** for BCCs. *Excision with 4mm margins* - Standard excision might be appropriate for BCCs on the trunk or extremities, but on the face, a **4mm margin** might lead to a larger cosmetic defect than necessary. - Although it provides histological confirmation, it doesn't offer the same **tissue-sparing advantage** as Mohs surgery for facial lesions, potentially resulting in larger scars.

Q: A patient consults a dermatologist about a skin lesion on her neck. Examination reveals a 1-cm diameter, red, scaly plaque with a rough texture and irregular margins. Biopsy demonstrates epidermal cells with large, pleomorphic, hyperchromatic nuclei. What is the most likely diagnosis?

Actinic keratosis. ***Actinic keratosis*** - This diagnosis aligns with the description of a **red, scaly plaque** with a **rough texture** and **irregular margins**, which are classic clinical features of actinic keratosis. - The biopsy findings of epidermal and dermal cells with **large, pleomorphic, hyperchromatic nuclei** are consistent with **atypical keratinocytes**, a hallmark of actinic keratosis, indicating **premalignant change**. *Dermal nevus* - A dermal nevus is a **benign melanocytic lesion** that typically presents as a smooth, flesh-colored to light brown papule or nodule, not a scaly or rough plaque. - Histologically, it would show nests of nevus cells primarily in the **dermis** without the significant cellular atypia described. *Junctional nevus* - A junctional nevus is a **benign melanocytic lesion** characterized by nests of nevus cells located at the **dermoepidermal junction**. - Clinically, it appears as a flat or slightly raised, well-demarcated macule or papule, usually uniform in color, lacking the scaly, rough, and irregular features of the presented lesion. *Compound nevus* - A compound nevus is a **benign melanocytic lesion** with nevus cell nests present at both the **dermoepidermal junction** and within the dermis. - It typically presents as a raised, pigmented papule or nodule with a smooth or slightly warty surface, not a scaly plaque with irregular margins.

Q: A child presents with linear verrucous plaques on the trunk, accompanied by vacuolization of keratinocytes in the stratum spinosum and stratum granulosum. What is the diagnosis?

Verrucous epidermal nevus. ***Verrucous epidermal nevus*** - The presence of **linear verrucous plaques** on the trunk, coupled with **vacuolization of keratinocytes** in the **stratum spinosum** and **stratum granulosum**, is characteristic of a verrucous epidermal nevus. - These lesions are **benign congenital malformations** of the epidermis that follow the lines of Blaschko. *Incontinentia pigmenti* - This condition presents with **pigmentary changes** (swirling hyperpigmentation) typically in a linear pattern, often preceded by **vesicular and verrucous stages**. - Histologically, it shows **eosinophilic spongiosis** and **dyskeratotic cells** in earlier stages, rather than significant keratinocyte vacuolization in the stratum spinosum and granulosum as the primary finding described here. *Delayed hypersensitivity reaction* - A delayed hypersensitivity reaction (e.g., contact dermatitis) typically presents as **erythema**, **edema**, **pruritus**, and **vesiculation**, without a primary verrucous nature. - Histologically, it would show **spongiosis** (intercellular epidermal edema) and a **lymphocytic infiltrate**, but not the prominent vacuolization described. *Linear Darier's disease* - **Darier's disease** (keratosis follicularis) is characterized by **greasy, hyperkeratotic papules** typically in seborrheic areas; the linear form follows Blaschko's lines. - Histologically, it is defined by **dyskeratosis** (corps ronds and grains) and **acantholysis** (suprabasal clefting), which are distinct from simple keratinocyte vacuolization.

Q: A 50-year-old man presents with a rapidly enlarging, painless nodule on his ear. A biopsy shows keratin pearls and atypical squamous cells. What is the diagnosis?

Squamous cell carcinoma. ***Squamous cell carcinoma*** - The presence of **keratin pearls** and **atypical squamous cells** on biopsy is pathognomonic for **squamous cell carcinoma**. - A **rapidly enlarging, painless nodule** on sun-exposed areas like the ear is a classical presentation for this type of skin cancer. *Basal cell carcinoma* - Characterized by **palisading nuclei** and **peripheral clefting** on histology, not keratin pearls. - Typically presents as a **pearly nodule with telangiectasias**, which differs from the description. *Actinic keratosis* - This is a **precancerous lesion** characterized by **atypical keratinocytes** in the basal epidermal layer, but not invasive growth or true keratin pearls. - While it can progress to squamous cell carcinoma, the biopsy findings here indicate a **frank malignancy**. *Keratoacanthoma* - This lesion can grow rapidly and has a dome-shaped appearance with a **central keratin plug**. - Histologically, it shows **well-differentiated squamous cells** with a distinctive **crater-like architecture** with "lip" configuration, but the presence of **atypical squamous cells** on biopsy favors SCC over this typically benign lesion.

Q: A 70-year-old man presents with a rough, scaly lesion on his face that does not heal. A biopsy shows atypical keratinocytes. What is the diagnosis?

Actinic keratosis. ***Correct: Actinic keratosis*** - A **rough, scaly lesion on sun-exposed skin** (like the face) in an elderly patient is characteristic of actinic keratosis. - A biopsy showing **atypical keratinocytes confined to the lower epidermis** confirms the diagnosis. Actinic keratosis is a pre-malignant lesion representing dysplastic proliferation of keratinocytes. - The atypia is **partial-thickness** (not full-thickness), which distinguishes it from SCC in situ. *Incorrect: Basal cell carcinoma* - BCC typically presents as a **pearly, translucent nodule with telangiectasias** or a **non-healing ulcer with rolled borders**. - Histologically, BCC shows **nests of basaloid cells with peripheral palisading**, not atypical keratinocytes. *Incorrect: Squamous cell carcinoma* - While SCC can appear as a **scaly, crusted, or ulcerated nodule** on sun-exposed areas, biopsy would show **full-thickness epidermal atypia** or **dermal invasion**. - Actinic keratosis is the **precursor lesion to SCC**, but the presence of only atypical keratinocytes without invasion indicates AK rather than invasive SCC. *Incorrect: Seborrheic keratosis* - Seborrheic keratoses are benign lesions with a characteristic **"stuck-on" appearance** and waxy or greasy surface. - Histology shows **proliferation of basaloid cells** and **horn cysts (pseudo-horn cysts)**, not atypical keratinocytes.

Q: A 30-year-old woman presents with a non-healing ulcer on her lower leg. A biopsy reveals neutrophilic infiltration. Which condition is likely?

Pyoderma gangrenosum. ***Pyoderma gangrenosum*** - This condition is characterized by rapidly enlarging, painful, **necrotic ulcers** with undermined violaceous borders, often triggered by trauma (pathergy). - Histologically, it shows a dense **neutrophilic infiltrate** without vasculitis, fitting the biopsy findings. *Basal cell carcinoma* - This is a common **skin cancer** that typically presents as a pearly nodule with rolled borders and telangiectasias, not usually a rapidly evolving necrotic ulcer. - Histology shows nests of basaloid cells with peripheral palisading, not primarily a neutrophilic infiltrate. *Squamous cell carcinoma* - This skin cancer often presents as a **scaly, erythematous patch, nodule, or ulcer**, especially in sun-exposed areas. - While it can ulcerate, the biopsy would show atypical keratinocytes with varying degrees of differentiation, not predominantly neutrophilic infiltration. *Kaposi sarcoma* - This is a **vascular cancer** associated with human herpesvirus 8 (HHV-8), commonly presenting as violaceous patches, plaques, or nodules. - Histology reveals a proliferation of spindle cells, vascular slits, and extravasated red blood cells, not a prominent neutrophilic infiltrate.

Question 1

Which finding best differentiates lymphomatoid papulosis from primary cutaneous CD30+ lymphoma?

Accepted Answer

Spontaneous resolution

Answer

Presence of large cells

Answer

CD30 positivity

Answer

Epidermal involvement

Question 2

A 30-year-old woman with history of melanoma presents at 10 weeks gestation with a new 6mm asymmetric pigmented lesion on the back. Most appropriate next step is:

Accepted Answer

Excisional biopsy under local anesthesia

Answer

Superficial shave biopsy

Answer

Monthly monitoring with dermoscopy

Answer

Defer biopsy until postpartum

Question 3

A 55-year-old male with history of liver transplant on tacrolimus presents with multiple scaly erythematous patches on sun-exposed areas, some showing mild induration. Most appropriate next step is:

Accepted Answer

Field therapy with 5-fluorouracil

Answer

Switch immunosuppression to sirolimus

Answer

Regular monitoring with photography

Answer

Prophylactic acitretin

Question 4

Which procedure is most appropriate for a 0.8cm superficial BCC on the cheek?

Accepted Answer

Mohs surgery

Answer

Curettage and electrodesiccation

Answer

Cryotherapy

Answer

Excision with 4mm margins

Question 5

A 60-year-old man with history of multiple non-melanoma skin cancers presents with a 1.5cm pearly nodule with telangiectasia on the right nasal ala, extending to the alar crease. He's on warfarin for mechanical heart valve (INR 2.8) and has previously developed keloids after surgery. Recent biopsy shows infiltrative BCC. Most appropriate management is:

Accepted Answer

Mohs surgery while continuing anticoagulation

Answer

Radiation therapy

Answer

Hedgehog inhibitor therapy

Answer

Wide local excision under local anesthesia

Question 6

A patient consults a dermatologist about a skin lesion on her neck. Examination reveals a 1-cm diameter, red, scaly plaque with a rough texture and irregular margins. Biopsy demonstrates epidermal cells with large, pleomorphic, hyperchromatic nuclei. What is the most likely diagnosis?

Accepted Answer

Actinic keratosis

Answer

Dermal nevus

Answer

Junctional nevus

Answer

Compound nevus

Question 7

A child presents with linear verrucous plaques on the trunk, accompanied by vacuolization of keratinocytes in the stratum spinosum and stratum granulosum. What is the diagnosis?

Accepted Answer

Verrucous epidermal nevus

Answer

Incontinentia pigmenti

Answer

Delayed hypersensitivity reaction

Answer

Linear Darier's disease

Question 8

A 50-year-old man presents with a rapidly enlarging, painless nodule on his ear. A biopsy shows keratin pearls and atypical squamous cells. What is the diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Basal cell carcinoma

Answer

Actinic keratosis

Answer

Keratoacanthoma

Question 9

A 70-year-old man presents with a rough, scaly lesion on his face that does not heal. A biopsy shows atypical keratinocytes. What is the diagnosis?

Accepted Answer

Actinic keratosis

Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

Answer

Seborrheic keratosis

Question 10

A 30-year-old woman presents with a non-healing ulcer on her lower leg. A biopsy reveals neutrophilic infiltration. Which condition is likely?

Accepted Answer

Pyoderma gangrenosum

Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

Answer

Kaposi sarcoma

Skin Tumors — MCQs

Skin Tumors — MCQs

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