Cytomorphological findings of Trichophyton rubrum infection in an elderly hypertensive woman.

Trichophyton is a dermatophytic fungi causing superficial skin infections which affects outermost layer of the epidermis, stratum corneum, and mainly involves feet, groin, scalp, and nails. Invasion into the dermis occurs mainly in immunocompromised patients. A 75-year-old hypertensive female presented with a nodular swelling on the dorsum of right foot for 1 month. The swelling was 1.0 × 1.0 cm and gradually progressive in nature. FNAC revealed many thin filamentous branching and fungal hyphae along with foreign body granulomas and suppurative acute inflammation. The swelling was excised and sent for histopathological examination which confirmed the above findings. Periodic Acid Schiff stain showed fungal hyphae in both cytology smear as well as histopathology section. On fungal culture, microconidia with septate hyphae suggestive of Trichophyton rubrum was seen. Trichophytons mainly affect immunocompromised and diabetic patients, however, may present as nodular lesions without any history of superficial dermatophytosis as seen in the present case. The characteristic cytological picture helped to clinch the diagnosis in this case and facilitated further management.