Incidental Found Fungal Growth in a Suspected Case of Fibrous Dysplasia of Left Shoulder: Case Report.

Introduction: Fibrous dysplasia is a rare, benign bone disorder characterized by fibro-osseous replacement of normal bone.

Case report: We report the case of a 22-year-old female who presented with chronic left arm pain and a history of pathological fracture of the left humerus. Radiological imaging revealed an ill-defined intramedullary mixed sclerotic and lytic lesion suggestive of fibrous dysplasia. The patient underwent bone curettage and grafting, and the sample was sent for histopathological examination. Surprisingly, the histology showed fungal spores, with no evidence of neoplasia. The patient had no known immunocompromised state or predisposing factors.

Conclusion: This case emphasizes the importance of considering rare infectious causes such as fungal osteomyelitis in the differential diagnosis of tumor-like bone lesions, even in immunocompetent individuals. Early tissue diagnosis is critical to avoid mismanagement and to initiate appropriate antifungal treatment.