Primary neoplasms of the carpal bones.

Primary neoplasms of the carpal bones are rare. We found 44 primary tumors of the carpal bones of 26,800 bone neoplasms (prevalence, 0.16%). Original histologic slides and original radiographs were reviewed in 36 and 29 cases, respectively. Thirty-eight tumors (86%) were benign; 6 (14%) were malignant. The average patient age was 35 years. Benign lesions were diagnosed at a younger age (32 years) than malignant lesions (58 years). Benign tumors occurred more frequently in males (23 of 38 patients); the 6 malignant lesions were equally distributed by gender (3 males and 3 females; 95% confidence interval, 11.8-88.2). The most common tumor was osteoid osteoma (11 cases); the most common malignant neoplasm was hemangioendothelial sarcoma (3). The most common locations were the scaphoid (13 cases) and capitate (10), which together accounted for 52% of all neoplasms. Tumors were identified in every carpal bone except the trapezium. The diagnosis of tumor in a carpal bone should be considered in the undiagnosed painful wrist, especially in younger patients without imaging abnormalities.