Variability of clinical presentation and diagnostic challenges in osteoarticular sporotrichosis: a case series

Osteoarticular sporotrichosis is the most common extracutaneous type of the disease and may occur either concomitantly with cutaneous lesions or as isolated musculoskeletal disease, the latter frequently resulting in delayed diagnosis. We describe five confirmed cases of osteoarticular sporotrichosis diagnosed between 2002 and 2023 at a university hospital in Brazil. Diagnosis was confirmed by fungal culture, with serology and histopathology used as complementary methods. Clinical and epidemiological data, radiologic findings, treatment, and outcomes were analyzed. Patients were 39 to 67 years of age and all had chronic conditions or alcoholism. Joint involvement most frequently affected the knee (four cases), followed by the wrist (three cases), and small joint of the hands (two cases), often with bone and periarticular tissue involvement. Three patients had concomitant cutaneous involvement. Diagnostic delays were frequent, reflecting the nonspecific clinical presentation and the tendency to misattribute symptoms to other musculoskeletal conditions. All patients received antifungal therapy with itraconazole and/or amphotericin B. Relapses were recorded in two patients, and there were irreversible sequelae such as chronic arthritis, joint stiffness, or deformity in all cases. Osteoarticular sporotrichosis should be considered in the differential diagnosis of chronic musculoskeletal conditions, including arthritis, osteomyelitis, synovitis, bursitis, and tenosynovitis, particularly in endemic regions. Early recognition and prolonged antifungal therapy are essential to achieve cure and prevent complications.