Endocrine: primary hyperparathyroidism: 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.

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Pathology · Endocrine: primary hyperparathyroidism

Sample item

A 50-year-old woman has recurrent renal stones, bone pain and constipation. Serum calcium is 12.2 mg/dL, phosphate is low and parathyroid hormone is raised. Which skeletal lesion is expected on histology of her bone?

AMosaic pattern of lamellar bone with cement linesBDense sclerosis with obliteration of the marrow spaceCOsteoclastic resorption with fibrosis and cystic brown tumoursDWidened unmineralised osteoid seams

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

The answer and the reasoning

C. Osteoclastic resorption with fibrosis and cystic brown tumours

Excess PTH increases osteoclast activity, producing subperiosteal and tunnelling resorption, marrow fibrosis and cystic spaces called brown tumours, together called osteitis fibrosa cystica. Most cases are now picked up biochemically before bone disease develops. A single parathyroid adenoma is the usual cause.

Option by option

A. Mosaic pattern of lamellar bone with cement lines
A mosaic pattern describes Paget disease, which has normal calcium and raised alkaline phosphatase.
B. Dense sclerosis with obliteration of the marrow space
Dense sclerosis with marrow obliteration describes osteopetrosis, with impaired osteoclast function.
C. Osteoclastic resorption with fibrosis and cystic brown tumours (correct)
Correct. Osteoclastic resorption with fibrosis and brown tumours is classic osteitis fibrosa cystica.
D. Widened unmineralised osteoid seams
Widened osteoid seams describe osteomalacia, in which calcium is low or normal and vitamin D is deficient.

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, Osteoclastic resorption with fibrosis and cystic brown tumours. Excess PTH increases osteoclast activity, producing subperiosteal and tunnelling resorption, marrow fibrosis and cystic spaces called brown tumours, together called osteitis fibrosa cystica.

Why is "Mosaic pattern of lamellar bone with cement lines" not the answer?

A mosaic pattern describes Paget disease, which has normal calcium and raised alkaline phosphatase.

Why is "Dense sclerosis with obliteration of the marrow space" not the answer?

Dense sclerosis with marrow obliteration describes osteopetrosis, with impaired osteoclast function.

Why is "Widened unmineralised osteoid seams" not the answer?

Widened osteoid seams describe osteomalacia, in which calcium is low or normal and vitamin D is deficient.

What concept does this question test?

It tests Endocrine: primary hyperparathyroidism in Pathology. Most cases are now picked up biochemically before bone disease develops. A single parathyroid adenoma is the usual cause.

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 Endocrine: primary hyperparathyroidism?

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.