Neoplasia: desmoid tumour and APC: practice question

A Pathology 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.

Try it

Pathology · Neoplasia: desmoid tumour and APC

Sample item

A man with familial adenomatous polyposis who underwent colectomy develops a firm infiltrating abdominal wall mass. Biopsy shows bland spindle cells in fascicles, with nuclear beta-catenin staining and no metastatic potential. What is the diagnosis?

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

The answer and the reasoning

D. Desmoid tumour (aggressive fibromatosis)

Desmoid tumours arise in FAP and Gardner syndrome, with APC or CTNNB1 mutations activating the Wnt pathway and nuclear beta-catenin. They infiltrate locally and recur after surgery but do not metastasise.

Option by option

  • A. Leiomyosarcoma

    Leiomyosarcoma is a pleomorphic malignant tumour that does metastasise.

  • B. Gastrointestinal stromal tumour

    GIST is KIT or DOG1 positive and arises in the gut wall.

  • C. Dermatofibrosarcoma protuberans

    DFSP has a storiform pattern, CD34 positivity and a COL1A1-PDGFB fusion.

  • D. Desmoid tumour (aggressive fibromatosis) (correct)

    Correct. Locally aggressive, non-metastasising fibroblastic tumour with nuclear beta-catenin.

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.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is D, Desmoid tumour (aggressive fibromatosis). Desmoid tumours arise in FAP and Gardner syndrome, with APC or CTNNB1 mutations activating the Wnt pathway and nuclear beta-catenin.

Why is "Leiomyosarcoma" not the answer?

Leiomyosarcoma is a pleomorphic malignant tumour that does metastasise.

Why is "Gastrointestinal stromal tumour" not the answer?

GIST is KIT or DOG1 positive and arises in the gut wall.

Why is "Dermatofibrosarcoma protuberans" not the answer?

DFSP has a storiform pattern, CD34 positivity and a COL1A1-PDGFB fusion.

What concept does this question test?

It tests Neoplasia: desmoid tumour and APC in Pathology. They infiltrate locally and recur after surgery but do not metastasise.

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 Neoplasia: desmoid tumour and APC?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.