Histological sections of hematoxylin-eosin–stained biopsy specimen showed hemorrhage and necrosis (Figure 2) with acute right-angle branching nonseptate hyphae (Figure 3). Polymerase chain reaction revealed a 100% DNA match with reference sequences for the species Rhizopus microsporus, Rhizopus oryzae, and Rhizopus oligosporus. The patient was treated successfully with wide local excision, amputation of the index finger, and posaconazole.