Mycology: Basidiobolus ranarum: practice question

A Microbiology 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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Microbiology · Mycology: Basidiobolus ranarum

Sample item

A 6-year-old boy has a painless, firm, woody swelling over the thigh for four months, with skin that slides over it. Biopsy shows broad sparsely septate hyphae surrounded by eosinophilic material (Splendore-Hoeppli phenomenon). Which organism is most likely?

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

The answer and the reasoning

D. Basidiobolus ranarum

Basidiobolus ranarum causes subcutaneous entomophthoromycosis of the trunk and limbs, typically in children, with hard painless swellings. The hyphae are broad with few septa and are cuffed by eosinophilic Splendore-Hoeppli material. Itraconazole, sometimes with potassium iodide, is used. Conidiobolus instead produces rhinofacial disease.

Option by option

  • A. Rhizopus arrhizus

    Rhizopus causes angioinvasive necrotic disease in immunocompromised hosts, not a painless woody mass.

  • B. Conidiobolus coronatus

    Conidiobolus coronatus typically causes nasal and rhinofacial swelling.

  • C. Madurella mycetomatis

    Madurella mycetomatis produces grains and draining sinuses, not this histology.

  • D. Basidiobolus ranarum (correct)

    Correct. A woody limb swelling with Splendore-Hoeppli material fits B. ranarum.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Basidiobolus ranarum. Basidiobolus ranarum causes subcutaneous entomophthoromycosis of the trunk and limbs, typically in children, with hard painless swellings.

Why is "Rhizopus arrhizus" not the answer?

Rhizopus causes angioinvasive necrotic disease in immunocompromised hosts, not a painless woody mass.

Why is "Conidiobolus coronatus" not the answer?

Conidiobolus coronatus typically causes nasal and rhinofacial swelling.

Why is "Madurella mycetomatis" not the answer?

Madurella mycetomatis produces grains and draining sinuses, not this histology.

What concept does this question test?

It tests Mycology: Basidiobolus ranarum in Microbiology. The hyphae are broad with few septa and are cuffed by eosinophilic Splendore-Hoeppli material. Itraconazole, sometimes with potassium iodide, is used. Conidiobolus instead produces rhinofacial disease.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Mycology: Basidiobolus ranarum?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.