Temporal progression of skeletal cystic angiomatosis.

Cystic angiomatosis is a rare, benign, multifocal disorder of bone and viscera, in which angiomatous deposits of both vascular and lymphatic elements result in bone lysis and organ dysfunction. We report on a case of late-onset cystic angiomatosis in a Caucasian woman who first presented at age 35 years with a lytic expansile lesion of the proximal humerus, initially diagnosed as low-grade hemangio-endothelioma. This was treated with injection of cement and prophylactic pinning. However, the lesion continued to grow, and, 5 years later, she was discovered to have disseminated bony involvement, initially thought to represent metastatic disease. However, further investigation revealed a diagnosis of cystic angiomatosis, and the patient was treated with bisphosphonates. Follow-up over a 15-year period since her initial presentation at age 35 years has shown osteosclerotic conversion of many of the lesions, with development of numerous pathologic stress fractures that have failed to heal, despite operative intervention.