Innocuous "foot lump" in patient with diabetes mellitus: A manifestation of phaeohyphomycosis.

Invasive mycotic infection presenting as "foot lump" in an immunocompetent patient is extremely rare. The case highlights the difficulty in diagnosis of fungal infections of foot including attempts to isolate the fungus and non-response to anti-fungal agents. A 64-year-old lady with T2DM for four years presented with painless, gradually progressive swelling over plantar aspect of left mid-foot for six months. Foot examination revealed soft-to-firm lump over the plantar aspect of left mid-foot obscuring the lateral longitudinal arch. No signs of inflammation or bony deformities were noticed. X-ray foot revealed radio-dense shadow in soft tissue without bone changes, corroborated by MRI. A diagnosis of lipoma, ganglion cyst, tubercular abscess and a fungal infection were considered. Aspirate cytology suggested the presence of Aspergillus hyphae although repeated cultures were unsuccessful. Medical management in form of itraconazole initially, followed by voriconazole was tried. However, there was no response to anti fungal agents and the lesion was surgically excised. Histopathological examination confirmed the presence of pigmented fungus (phaehyphomycosis).