Cytohistomorphology of subcutaneous phaeohypomycosis
A 40-year-old lady presented with a soft, nodular, mobile swelling of size 3.0 cm × 2.0 cm over the right forearm near the wrist joint; radiograph showed a soft-tissue swelling without bone involvement. Clinically, suspected to be ganglion with the differential diagnosis of soft-tissue tumor []. fine-needle aspiration (FNA) yielded thick mucoid material. Leishman stained cytosmears showed numerous neutrophils, foamy macrophages, macrophages containing coarse dark granular pigments within the cytoplasm along with many degenerated cells, lymphocytes and occasional multinucleated giant cells []. On questioning the patient gave a history of injury with wooden splinter. Considering the clinical and cytomorpholgic features, a diagnosis of acute on the chronic inflammation with a possibility of fungal infection was offered and advised excision biopsy.\nGross examination of the excised specimen showed a grey white ovoid tissue measuring 3.0 cm × 2.0 cm, cut section showed solid grey yellow and grey white area with focal black granular areas. Hematoxylin and eosin (H and E) stained microsections showed fungal colonies comprising of closely packed brown colored septate hyphae with acute angle branching and of narrow width along with eosinophilic Splenore-Hoepplie material at the periphery []. Periodic acid-Schiff (PAS) stain revealed positive magenta colored hyphae []. The surrounding fibrofatty tissue showed dense infiltrate of neutrophils, lymphocytes, eosinophils, foamy macrophages, macrophages containing coarse dark brown black colored pigments within the cytoplasm along with many multinucleated giant cells around the fungal colonies [].\nNo fungal hyphae were seen inside the giant cells. However, retrospective review of the routine cytosmears revealed focal dark brown black colored pigment with unstained hyphae like structures at the periphery, which was missed in the initial examination []. The case was finally diagnosed as subcutaneous phaeohypomycosis. Fungal culture was not done in this case.