Rhinoscleroma — DTM&H MCQ

Correct answer: A — Rhinoscleroma

The correct answer is A, rhinoscleroma. The two-year history of a slowly destructive nasal ulcer with cartilage loss, combined with histology showing plasma cells, macrophages and Mikulicz cells containing gram-negative coccobacilli, is diagnostic of chronic granulomatous infection with Klebsiella rhinoscleromatis. Mikulicz cells are large foamy macrophages packed with the causative organism and are considered a pathognomonic histological hallmark of this disease. Rhinoscleroma classically progresses through catarrhal, granulomatous and sclerotic stages over months to years, matching the chronic destructive course described, and is endemic in parts of Africa (including Sudan), Central America and Southeast Asia. Diagnosis is confirmed by this combination of clinical course, endemic exposure and characteristic histopathology, and management requires prolonged antibiotics such as ciprofloxacin or co-trimoxazole, sometimes with surgery for airway obstruction. Why the other options are wrong: E. Rhinosporidiosis: Caused by Rhinosporidium seeberi, this produces friable polypoidal, vascular masses with sporangia containing endospores on histology, not Mikulicz cells or gram-negative coccobacilli, and it is not typically destructive of cartilage. D. Nasal leishmaniasis: Mucocutaneous leishmaniasis shows amastigotes within macrophages on Giemsa stain, not Mikulicz cells or bacilli, and is geographically and histologically distinct despite also causing destructive facial lesions. C. Wegener granulomatosis (granulomatosis with polyangiitis): This is a necrotising vasculitis with granulomas and is ANCA-associated; biopsy shows vasculitis and necrosis, not an infective organism or Mikulicz cells, and it is not linked to a specific bacterium. B. Nasal lymphoma: Biopsy would show a monoclonal lymphoid infiltrate with malignant cytology, not plasma cells, macrophages and bacteria-laden Mikulicz cells. Key point: Mikulicz cells containing gram-negative coccobacilli on nasal biopsy are pathognomonic for rhinoscleroma caused by Klebsiella rhinoscleromatis.

Reference: DermNet NZ, Rhinoscleroma, https://dermnetnz.org/topics/rhinoscleroma