An atypically located large subchondral cyst in an osteoarthritic hip joint: a case report

INTRODUCTION Osteoarthritic subchondral cysts within or around the hip joint can sometimes be difficult to distinguish from primary osseous and soft tissue tumors due to their radiological appearance and uncommon location. CASE PRESENTATION We report the case of a 74-year-old Turkish man with a subchondral cyst arising from the hip joint, eroding the acetabulum and located on the medial side of the iliac bone, which imitated a soft tissue tumor. This cystic lesion was resected and the results of histopathological analysis of tissue samples were found to be consistent with an osteoarthritic cyst. CONCLUSIONS The present case illustrates how an osteoarthritic subchondral cyst can grow into the soft tissue planes in the presence of destruction of the articular cartilage and subchondral bone continuity, and present as an apparent soft tissue tumor.