Skin Tumors Practice Questions

Q: A 52-year-old man presents with a rapidly growing, dome-shaped nodule on his right arm that developed over 6 weeks. Examination reveals a 2 cm, symmetrical, crateriform nodule with a central keratin plug. Which of the following is the most likely diagnosis?

Keratoacanthoma. ***Keratoacanthoma*** - The rapid growth over 6 weeks and the classic description of a **dome-shaped, crateriform nodule with a central keratin plug** are highly characteristic of a keratoacanthoma. - While histologically similar to well-differentiated squamous cell carcinoma, its distinct clinical presentation with spontaneous regression potential often differentiates it. *Squamous cell carcinoma* - Although it can present as a nodule, it typically exhibits slower growth and is less likely to have the classic **crateriform shape with a central keratin plug** that rapidly evolves over weeks. - Aggressive types can grow rapidly but often present with ulceration or induration rather than the specific dome-shaped morphology described. *Basal cell carcinoma* - Usually presents as a **pearly nodule** with telangiectasias, often with a rolled border, and grows slowly over months to years. - It lacks the characteristic **crateriform appearance** and rapid growth seen in this case. *Melanoma* - Characterized by asymmetry, irregular borders, varied colors, and a diameter greater than 6 mm (ABCDEs). - While some nodular melanomas can grow rapidly, they typically lack the distinct **crateriform morphology** and central keratin plug.

Q: A 60-year-old white man with a past medical history significant for hypertension and hyperlipidemia presents to his family medicine physician with concerns about a 'spot' on his ear. He has been a construction worker for 35 years and spends most of his time outside. His family history is insignificant. On physical examination, there is a dark lesion on his left ear. The patient states that he has always had a mole in this location but that it has recently become much larger. A review of systems is otherwise negative. Which of the following lesion characteristics would be MOST reassuring among the given options?

Single, dark color. ***Single, dark color*** - A **single, uniform dark color** in a mole is a reassuring characteristic, indicating a stable pigmentation pattern, as opposed to multiple colors or shades which are concerning for melanoma [1]. - While the patient notes the mole has grown, a uniform color suggests it has maintained its benign pigment distribution rather than showing chaotic growth patterns [1]. - This is the most reassuring finding among the options presented. *Changing over time* - Any **change in an existing mole**, whether in size, shape, color, or elevation (the "E" in ABCDE criteria), is the most significant warning sign for potential malignancy, making it highly concerning [1]. - The patient's statement that the mole has "recently become much larger" directly points to this concerning characteristic [1]. *Lesion asymmetry* - **Asymmetry** ("A" in ABCDE) means that if you draw a line through the mole, the two halves do not match, which is a key indicator of potential melanoma and is not reassuring [1]. - Benign moles are typically symmetrical. *Irregular, indistinct borders* - **Irregular or indistinct borders** ("B" in ABCDE) are a hallmark characteristic of melanoma, as malignant cells tend to invade surrounding tissue in an uneven manner [1]. - Benign moles usually have smooth, well-defined borders.

Q: Rodent ulcer is

Basal cell carcinoma. ***Basal cell carcinoma*** - The term **"rodent ulcer"** is a historical and descriptive term for a specific type of **basal cell carcinoma (BCC)**, characterized by a **pearly raised border** and a central ulceration. - This appearance, with its rolled edges and sometimes visible telangiectasias, gives the impression of a lesion gnawing away at the tissue, hence the "rodent" description. *Squamous cell carcinoma* - While also a common skin cancer, **squamous cell carcinoma (SCC)** typically presents as a **scaly, crusted nodule or plaque** with irregular borders, or a non-healing ulcer that does not have the classic rolled border of a rodent ulcer. - It is more prone to **metastasis** than BCC. *Rhinophyma* - **Rhinophyma** is a severe form of **rosacea** that causes a bulbous, red, and swollen nose due to hyperplasia of sebaceous glands and connective tissue. - It is a **benign condition** and not a form of skin cancer or ulcer. *Adenocarcinoma (glandular cancer)* - **Adenocarcinoma** is a type of cancer that originates in **glandular tissue**, such as in the breast, prostate, colon, or lung. - It is **not a primary skin cancer** and does not typically present as a "rodent ulcer" on the skin surface.

Q: Most common subtype of Rodent ulcer is:

Nodular. ***Nodular*** - The **nodular** subtype is the most common presentation of **basal cell carcinoma (rodent ulcer)**, accounting for 60-80% of cases. - It typically appears as a **pearly nodule** with rolled borders and telangiectasias. *Superficial* - The **superficial** subtype is the second most common, accounting for 15-20% of basal cell carcinomas. - It presents as a **red, scaly patch**, often mistaken for eczema or psoriasis. *Pigmented* - The **pigmented** subtype is less common, characterized by the presence of **melanin**, making it appear dark brown or black. - It can be confused with melanoma due to its dark coloration. *Cystic* - The **cystic** subtype is a rare form of basal cell carcinoma, characterized by a **fluid-filled lesion**. - It often appears as a translucent nodule with a soft, jelly-like consistency.

Q: A farmer presented with a black mole on the cheek. It increased in size, more than 6mm with irregular borders and a central black lesion, what could be the diagnosis?

Superficial spreading melanoma. ***Superficial spreading melanoma*** - This is the most common type of melanoma and often presents as a **mole with irregular borders**, varying colors, and a diameter greater than 6mm, consistent with the description. - The lesion typically grows **radially** across the skin surface before beginning vertical growth, indicated by the increase in size. *Acral lentigo melanoma* - This type of melanoma primarily affects the **palms, soles, and nail beds**, which is inconsistent with a lesion on the cheek. - It often appears as a **dark brown or black patch** that slowly enlarges, but its location is characteristic. *Lentigo maligna melanoma* - This melanoma typically occurs in **chronically sun-damaged skin** of the elderly, often on the head and neck, but usually presents as a **flat, irregularly shaped, tan or brown patch** with varying shades, which may not fit the description of a central black lesion within a larger mole. - It has a dominant **radial growth phase** and progresses slowly over many years before developing a nodular component. *Nodular melanoma* - This type is characterized by its **rapid vertical growth** and appearance as a **raised, dark, often dome-shaped lesion** from the outset. - While it can be black, the description of an "increased in size" mole with irregular borders and a central black lesion points more towards a spreading type rather than a rapidly growing nodule from the beginning.

Q: A 50-year-old woman with long-standing discoid lupus develops a rapidly growing keratotic nodule within an old lesion. Most appropriate management is:

Surgical excision with margins. ***Surgical excision with margins*** - A rapidly growing **keratotic nodule** within a long-standing **discoid lupus erytematosus (DLE)** lesion is highly suspicious for transformation into **squamous cell carcinoma (SCC)**. - **Surgical excision** with appropriate margins is the definitive diagnostic and therapeutic approach for suspected SCC. *Start topical steroids* - Topical steroids are used for the inflammatory component of DLE but will not address a potentially malignant **keratotic nodule**. - Delaying definitive treatment for a suspected malignancy with steroids could lead to progression. *Increase hydroxychloroquine dose* - **Hydroxychloroquine** is a systemic treatment for DLE but works slowly and is not effective for a rapidly growing, potentially malignant nodule. - It would not provide immediate or curative treatment for a suspected **squamous cell carcinoma**. *Add systemic steroids* - Systemic steroids treat the inflammatory and autoimmune aspects of DLE, but they would not eliminate a **neoplastic growth**. - While they might transiently reduce associated inflammation, they do not treat or prevent the progression of skin cancer.

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: Compare the following treatment modalities for actinic keratoses: 1. Cryotherapy a. Field treatment, high clearance 2. 5-fluorouracil b. Targets single lesions 3. Photodynamic therapy c. Requires multiple office visits

1-b, 2-a, 3-c. ***1-b, 2-a, 3-c*** - This option correctly matches **cryotherapy** with targeting **single lesions**, **5-fluorouracil** with **field treatment** and **high clearance**, and **photodynamic therapy** with requiring **multiple office visits**. - **Cryotherapy** is a localized treatment, **5-fluorouracil** is applied broadly to treat multiple lesions, and **PDT** involves an initial sensitizer application followed by light exposure. *1-a, 2-b, 3-c* - This option incorrectly states **cryotherapy** as a field treatment with high clearance because **cryotherapy** is primarily used for **individual lesions**. - It also inaccurately assigns **5-fluorouracil** to targeting single lesions, as **5-FU** is known for its effectiveness as a **field treatment**. *1-b, 2-c, 3-a* - This option incorrectly associates **5-fluorouracil** with requiring multiple office visits. While it is applied over several days or weeks, these are typically at-home treatments, not numerous in-office visits. - It also incorrectly matches **photodynamic therapy** with field treatment and high clearance, whereas while PDT is a field treatment, its clearance rates can vary, and it usually requires multiple visits. *1-c, 2-a, 3-b* - This response inaccurately suggests that **cryotherapy** requires multiple office visits, when in fact it is often a **single-session treatment** per lesion. - It also wrongly correlates **photodynamic therapy** with targeting single lesions, as **PDT** is typically applied over a **broader area** for field treatment.

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.

Question 1

A 52-year-old man presents with a rapidly growing, dome-shaped nodule on his right arm that developed over 6 weeks. Examination reveals a 2 cm, symmetrical, crateriform nodule with a central keratin plug. Which of the following is the most likely diagnosis?

Accepted Answer

Keratoacanthoma

Answer

Squamous cell carcinoma

Answer

Basal cell carcinoma

Answer

Melanoma

Question 2

A 60-year-old white man with a past medical history significant for hypertension and hyperlipidemia presents to his family medicine physician with concerns about a 'spot' on his ear. He has been a construction worker for 35 years and spends most of his time outside. His family history is insignificant. On physical examination, there is a dark lesion on his left ear. The patient states that he has always had a mole in this location but that it has recently become much larger. A review of systems is otherwise negative. Which of the following lesion characteristics would be MOST reassuring among the given options?

Accepted Answer

Single, dark color

Answer

Changing over time

Answer

Lesion asymmetry

Answer

Irregular, indistinct borders

Question 3

Rodent ulcer is

Accepted Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

Answer

Rhinophyma

Answer

Adenocarcinoma (glandular cancer)

Question 4

Most common subtype of Rodent ulcer is:

Accepted Answer

Nodular

Answer

Superficial

Answer

Pigmented

Answer

Cystic

Question 5

A farmer presented with a black mole on the cheek. It increased in size, more than 6mm with irregular borders and a central black lesion, what could be the diagnosis?

Accepted Answer

Superficial spreading melanoma

Answer

Acral lentigo melanoma

Answer

Lentigo maligna melanoma

Answer

Nodular melanoma

Question 6

A 50-year-old woman with long-standing discoid lupus develops a rapidly growing keratotic nodule within an old lesion. Most appropriate management is:

Accepted Answer

Surgical excision with margins

Answer

Start topical steroids

Answer

Increase hydroxychloroquine dose

Answer

Add systemic steroids

Question 7

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 8

Compare the following treatment modalities for actinic keratoses:
1. Cryotherapy a. Field treatment, high clearance
2. 5-fluorouracil b. Targets single lesions
3. Photodynamic therapy c. Requires multiple office visits

Accepted Answer

1-b, 2-a, 3-c

Answer

1-a, 2-b, 3-c

Answer

1-b, 2-c, 3-a

Answer

1-c, 2-a, 3-b

Question 9

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 10

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

Skin Tumors — MCQs

Skin Tumors — MCQs

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