Answer to April 2022 Photo Quiz

A diagnosis of Schistosoma haematobium infection was made based on the appearance of an adult probable male worm within a lymphovascular space at the deep cauterized edge of the bladder biopsy. Characteristic eggs measuring up to 180 µm in length with terminal spines were seen in other sections, surrounded by an eosinophil-rich infiltrate. Adult Schistosoma haematobium worms normally reside in the bladder venous plexus, and may rarely be seen in tissue biopsy. The diagnosis was later confirmed through sequencing of the D2 region of the 28S rRNA gene from the formalin-fixed paraffin-embedded tissue (1). The patient was treated with praziquantel (40 mg/kg total) and has remained clinically well since.

Genitourinary schistosomiasis is caused by the trematode (fluke) Schistosoma haematobium, which is endemic in Africa, areas of the Middle East, and in Corsica, France, and occasionally by the cattle schistosome Schistosoma bovis or hybrids with this species (2). S. haematobium resides in the bladder venous plexus. While Schistosoma mansoni is also present in Mauritania, this species has a characteristic lateral (not terminal) spine and typically leads to intestinal disease. Schistosoma spp. are transmitted through skin contact with cercariae in contaminated freshwater where specific intermediate host snails live. The most common urinary symptoms include hematuria and dysuria. Imaging findings usually consist of nodular bladder wall thickening in the acute phase and fibrosis with calcifications in the chronic phase (3). While not found in this case, diagnosis is typically made by the finding of eggs in concentrated urine specimens (4). S. haematobium infection is considered a risk factor for the development of bladder squamous cell carcinoma (5, 6). Rarely, development of a polypoid mass can be seen in the chronic phase of infection, which mimics carcinoma, as seen in this case (7).

Eliciting a travel and exposure history in individuals with terminal hematuria can provide clues to the diagnosis, which is important due to the simplicity of treatment and potential for prevention of chronic complications.