Background: Fine needle aspiration (FNA) cytology has great potential for the diagnosis of fungal lesions and other opportunistic infections, the frequency of which is rising due to immunosuppression, travel and environmental exposure. However, reports on FNA diagnosis of fungal lesions are rare.
Case: A 40-year-old male juvenile diabetic presented with a 5 x 4-cm swelling over the upper part of the left arm. He had a recent history of a left nephrectomy for renal cell carcinoma followed by radiotherapy. At the time of presentation, he was also receiving chemotherapy and interferon alpha-2a for a suspected pulmonary metastasis. FNA smears from the swelling showed an inflammatory exudate rich in neutrophils and a few septate fungal hyphae that branched at acute angle. Gomori's silver methenamine stain and periodic acid-Schiff stain revealed numerous fungal hyphae. The provisional diagnosis based on the cytomorphologic features was aspergillosis. However, culture of the aspirate confirmed the fungus to be of the Verticillium species. The lesion on the left arm responded to antifungal therapy, and the swelling disappeared gradually.
Conclusion: FNA cytology was very useful in the diagnosis of a rare fungal lesion that was not clinically suspected in spite of the fact that the patient was a highly susceptible candidate for it.