[Osteoblastoma in the os hamatum: a rare case report].

Osteoblastoma in the os hamatum is rarely seen. Although curettage and grafting seems to be disadvantageous, it offers advantages in the functional protection in the treatment of carpal bone-located osteoblastoma. In a 39-year-old housewife who was admitted with painful left wrist through all day for the past one year, physical examination revealed painful hypothenar region with the wrist adduction to the ulna. Radiography showed radial inclination of the wrist, ring appearance in the scaphoid bone, and slight radiolucency in the hamatum and adjacent bones. Computed tomography demonstrated an expanded lesion which separated the surrounding tissue with a thin edge layer and perforated the cortex mildly. Intralesional curettage was performed. The pathological examination of the specimen obtained was consistent with osteoid osteoma or osteoblastoma. Curettage and grafting were performed in case of recurrence. In this article, we present a rare case of carpal bone and hamatum-located osteoblastoma. The patient was free of pain with normal wrist functions at 16 months postoperatively.