Iodine-125 seeds in prostatic transurethral resection: Differential diagnosis with schistosome eggs

The presence of foreign bodies in a prostate transurethral resection may pose a histopathological challenge. A 65-year-old white man with urinary obstructive symptoms was subjected to a transurethral resection. Histopathology showed a squamous cell carcinoma affecting prostatic ducts and multiple foreign bodies; their differential diagnosis was between iodine-125 seeds and Schistosoma sp. eggs, as both can show oval morphology and terminal spines. The seeds are irregular, homogeneous and solid, unlike Schistosoma eggs that are heterogeneous, with a lytic appearance and some embryonated or calcified. The seeds are located in prostatic ducts inducing periductal fibrosis whereas the Schistosoma sp. eggs are found in the stroma inducing desmoplasia and granulomas. The seeds are associated with a lymphoplasmacytic infiltrate while the eggs are surrounded by eosinophils.