Aneurysmal bone cyst of the wrist hamate: a case report and literature review / 中华骨科杂志

ABSTRACT

A rare instance of an aneurysmal bone cyst (ABC) in the wrist hamate of a 30-year-old male were reported in this case report. The patient exhibited a 1.5 cm mass on the dorsal ulnar side of the right wrist, which was non-tender, with normal overlying skin temperature and preserved wrist flexion. Radiographic evaluation revealed a deformed hamate with extensive cystic degeneration and minimal subchondral bone. Computed tomography (CT) scans highlighted clear osteolytic changes, including a visible bony crest. Magnetic resonance imaging (MRI) depicted mixed signal intensity on T1 and T2 weighted images. A biopsy indicated thinning and softening of the hamate's dorsal cortex, revealing eroded bone and dark red soft tissue. Histopathological analysis confirmed the diagnosis of an aneurysmal bone cyst. The patient underwent resection of the right wrist hamate, bone grafting from the iliac crest, and stabilization with Kirschner wire, resulting in fusion of the capitate-hamate and fourth and fifth carpometacarpal joints. The postoperative course involved immobilization with plaster for six weeks, and a 15-month follow-up indicated no recurrence. A review of the literature revealed that ABCs involving carpal bones are rare, predominantly occurring in individuals under 30 years of age. Clinical manifestations typically include wrist pain, occasional mild swelling, limited wrist mobility, and reduced hand strength. Radiological findings are characterized by osteolytic changes with MRI showing low T1WI and high T2WI signal intensity, and liquid levels on axial images. Treatment predominantly involves osteotomy or curettage with bone grafting. Diagnostic hallmarks include osteoclast-like multinucleated giant cells, ossified areas, and cystic cavities partitioned by fibrous septa. Our findings, consistent with the literature, suggest a favorable prognosis for carpal bone ABCs when treated appropriately.