Cryptococcal infection of the femoral bone similar with pathologic features of vascular tumors: a case report and review of literature

A rare case is presented of a 62-year-old man with primary isolated cryptococcal femoral osteomyelitis. Magnetic resonance imaging (MRI) revealed osteolytic destruction of his left femur. Biopsy was performed firstly. Under microscope, the lesion was compose of numerous large mononuclear cells, scattered multinucleated giant cells, a few lymphocytes and neutrophils, necrosis with serious artificial deformation. By immunohistochemistry (IHC), only CD31 and CD68 were positive, while CK, CK8/18, EMA, P63, CK7, CK20, PSAP, PSA, CD34 negative. It was considered a low grade vascularsarcoma, but not confirmed. Then the operation was done. Surgical specimen showed a lot of red-sphere materials in most cells cytoplasm. The Gomorra methenamine silver staining and PAS revealed the mucopolysaccharide-containing capsule of the Cryptococcus. Laboratory culture of lesion liquid grew a kind of yeast at 37°C. Cryptococcal femoral osteomyelitis was diagnosed at last. The patient is good now after the thorough debridement and anti-fungal treatment.