A 25 year old male presents to the clinic with a lesion on his penis. On examination he was noted to have a beefy red ulcer on the glans which bled when touched. Smear taken from the ulcer showed gram-negative intracytoplasmic cysts filled with deeply staining bodies that had a safety-pin appearance. What is he most likely suffering from?
First, I need to recall the differential diagnoses for genital ulcers. Common ones include syphilis, chancroid, and donovanosis. Syphilis presents as a painless chancre, usually firm and not bleeding easily. Chancroid is painful, with a soft base and purulent exudate. Donovanosis, caused by Klebsiella granulomatis, has a beefy red, bleeding ulcer. The safety-pin appearance is classic for Donovan bodies, which are intracytoplasmic inclusions in macrophages, characteristic of donovanosis.
Wait, the question mentions gram-negative intracytoplasmic cysts. So, the safety-pin appearance is key here. Syphilis is caused by Treponema pallidum, which is a spirochete, not seen as gram-negative. Chancroid is caused by Haemophilus ducreyi, which is gram-negative but doesn't form the safety-pin structures. Donovani bodies (another name for Donovan bodies) are the key here. So the correct answer should be donovanosis.
Looking at the options, the distractors are likely syphilis, chancroid, and maybe something else like LGV. The smears for LGV caused by Chlamydia trachomatis serovars L1-L3 would show intracellular inclusions but not the safety-pin appearance. So the correct answer is donovanosis, option C. The other options don't fit the safety-pin morphology. So the answer must be C.
**Core Concept**
This question tests the identification of genital ulcer disease based on clinical presentation and microscopic findings. The safety-pin appearance of intracytoplasmic inclusions is a hallmark histopathological feature of *Donovan bodies*, diagnostic for granuloma inguinale (donovanosis), caused by *Klebsiella granulomatis*.
**Why the Correct Answer is Right**
The beefy red, bleeding ulcer with a safety-pin appearance on smear is pathognomonic for donovanosis. *K. granulomatis* infects macrophages, forming intracytoplasmic inclusions (Donovan bodies) that appear as elongated, gram-negative structures with two deeply stained poles and a pale center. The ulcer’s friable, beefy appearance and the safety-pin morphology distinguish it from other genital ulcers like syphilis (painless, firm chancre) or chancroid (painful, soft ulcer with purulent exudate).
**Why Each Wrong Option is Incorrect**
**Option A:** *Syphilis (Treponema pallidum)* causes painless chancres without intracellular inclusions. Histopathology shows a dense lymphocytic infiltrate, not safety-pin structures.
**Option B:** *Chancroid (Haemophilus ducreyi)* presents as a painful ulcer with undermined edges and soft base. Smears show gram-negative rods but no Donovan bodies.
**Option D:** *Lymph