Neoplasia: chondroblastoma: 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: chondroblastoma

Sample item

A 16-year-old boy with open growth plates has knee pain. Radiographs show a well-defined lytic lesion with a sclerotic rim in the proximal tibial epiphysis. Histology shows polygonal cells with grooved nuclei, scattered giant cells, pericellular chicken-wire calcification, and S-100 positivity. What is the diagnosis?

AOsteoblastomaBGiant cell tumour of boneCChondroblastomaDClear cell chondrosarcoma

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

The answer and the reasoning

C. Chondroblastoma

Chondroblastoma is a benign cartilage-forming tumour of the epiphysis in adolescents before physeal closure, with chondroblasts showing nuclear grooves, giant cells and chicken-wire calcification. Giant cell tumour occurs mainly after the growth plate closes and lacks cartilage matrix.

Option by option

A. Osteoblastoma
Osteoblastoma is a bone-forming tumour of the posterior spine elements with osteoid, not an epiphyseal chondroid lesion.
B. Giant cell tumour of bone
Giant cell tumour of bone occurs in skeletally mature adults and does not show chondroid calcification.
C. Chondroblastoma (correct)
Correct. Epiphyseal location in an adolescent, S-100 positive chondroblasts and chicken-wire calcification identify chondroblastoma.
D. Clear cell chondrosarcoma
Clear cell chondrosarcoma is a rare low-grade malignancy of adults with clear cells, not an adolescent tumour with a sclerotic rim.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, Chondroblastoma. Chondroblastoma is a benign cartilage-forming tumour of the epiphysis in adolescents before physeal closure, with chondroblasts showing nuclear grooves, giant cells and chicken-wire calcification.

Why is "Osteoblastoma" not the answer?

Osteoblastoma is a bone-forming tumour of the posterior spine elements with osteoid, not an epiphyseal chondroid lesion.

Why is "Giant cell tumour of bone" not the answer?

Giant cell tumour of bone occurs in skeletally mature adults and does not show chondroid calcification.

Why is "Clear cell chondrosarcoma" not the answer?

Clear cell chondrosarcoma is a rare low-grade malignancy of adults with clear cells, not an adolescent tumour with a sclerotic rim.

What concept does this question test?

It tests Neoplasia: chondroblastoma in Pathology. Giant cell tumour occurs mainly after the growth plate closes and lacks cartilage matrix.

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: chondroblastoma?

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.