Subcutaneous Chromoblastomycosis Caused by Rhinocladiella Species in Rhode Island

Chromoblastomycosis (CBM) is a subcutaneous fungal infection caused by one of several dematiaceae molds with melanotic pigmentation in the cell walls. CBM is characterized by various clinical and dermatological features, leading to common misdiagnosis as several other infectious and noninfectious diseases. Histopathologically, in addition to the pathognomonic muriform cells or "copper pennies," the causative agents of subcutaneous and systemic mycosis lead to a granulomatous reaction due to the influx of mononuclear phagocytic cells and a suppurative infiltrate of neutrophils. Treatment of CBM can be challenging as no standard treatment has been established. This case highlights a rare presentation of subcutaneous chromoblastomycosis caused by Rhinocladiella species in the United States with satisfactory management. It emphasizes the role of occupational and exposure history, keeping a high index of suspicion in cases of verrucous nodules or plaques with new satellite lesions on extremities, and recognizing this entity's distinct dermatopathology characteristics.