Skin tumours: eccrine porocarcinoma: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Skin tumours: eccrine porocarcinoma

Sample item

An elderly man has a slowly enlarging, ulcerated, friable nodule on the lower leg that arose in a long-standing small papule. Histology shows ductal differentiation with atypical cuboidal cells, nuclear pleomorphism and dermal invasion. What is the diagnosis?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Eccrine porocarcinoma

Eccrine porocarcinoma is a rare malignant adnexal tumour, often arising from a pre-existing eccrine poroma, usually on the lower limbs or head of older adults. It can metastasise to lymph nodes, so wide excision and nodal assessment are required.

Option by option

  • A. Dermatofibroma

    Dermatofibroma is a benign firm dermal nodule that does not ulcerate.

  • B. Basal cell carcinoma

    Basal cell carcinoma shows peripheral palisading of basaloid cells, not ductal differentiation.

  • C. Keratoacanthoma

    Keratoacanthoma has a central keratin-filled crater and grows quickly over weeks.

  • D. Eccrine porocarcinoma (correct)

    Correct. Malignant eccrine ductal differentiation in a lower-limb nodule defines porocarcinoma.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is D, Eccrine porocarcinoma. Eccrine porocarcinoma is a rare malignant adnexal tumour, often arising from a pre-existing eccrine poroma, usually on the lower limbs or head of older adults.

Why is "Dermatofibroma" not the answer?

Dermatofibroma is a benign firm dermal nodule that does not ulcerate.

Why is "Basal cell carcinoma" not the answer?

Basal cell carcinoma shows peripheral palisading of basaloid cells, not ductal differentiation.

Why is "Keratoacanthoma" not the answer?

Keratoacanthoma has a central keratin-filled crater and grows quickly over weeks.

What concept does this question test?

It tests Skin tumours: eccrine porocarcinoma in Dermatology. It can metastasise to lymph nodes, so wide excision and nodal assessment are required.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Skin tumours: eccrine porocarcinoma?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.