Abstract
BACKGROUND: Cryptococcus neoformans is an opportunistic fungal pathogen widely distributed in nature, commonly found in soil and bird droppings such as pigeons. Cryptococcal osteomyelitis is usually found in immunocompromised patients, in an unusual condition Cryptococcus invades the bone. It usually occurs as a part of disseminated infection and is rarely isolated, and isolated cryptococcal osteomyelitis of the radius is rarer. CASE PRESENTATION: We report a case of a 41-year-old woman with no underlying disease who presented with progressive distal swelling of the left forearm. The patient was initially suspected by local doctors of a malignant bone tumor. For further diagnosis, we performed a computed tomography-guided biopsy of the radius and found granulomatous inflammation with massive macrophage infiltration and a specific stain showing mycosis. Genetic testing revealed a high abundance of Cryptococcus neoformans. We performed debridement of the radius and filled the bone defect with antifungal calcium sulfate. Fluconazole was taken orally for 3 months after operation. No recurrence was found in the 15-month follow-up. CONCLUSION: It is the second case of Cryptococcus osteomyelitis as the only manifestation of extrapulmonary disease since 1973. It should be a safe and effective method to eliminate dead space, release antifungal drugs for a long time and increase bone stability by filling bone defect with antifungal drugs and calcium sulfate bone powder.