A Lytic Lesion in Proximal Phalanx of Hand
Tumors of the hand are mostly benign painless lesions. Enchondromas are the most common primary bone tumors of the hand, comprising up to 70–90% of cases. Aneurysmal bone cysts (ABCs) are commonly found in long bones. Atypical presentation in hand may mimic other bone lesions of the hand like enchondroma. Other bone tumors and tumor-like lesions in the hand include simple bone cyst (SBC), giant cell tumor (GCT), fibrous tumors, and vascular tumors. Some of these benign tumors can have similar clinical and radiological presentations. However, the different natural courses of the diseases make an accurate diagnosis essential. A percutaneous biopsy can be done to diagnose the lesions, but they are invasive. Magnetic resonance imaging (MRI) can differentiate between the common benign tumors of the hand, but it is not definitive. A diagnostic approach to lytic lesions of the hand is lacking in the literature.

A 25-year-old lady presented with a painless right index finger swelling for the past 6 months. The patient sustained a minor trauma 1 year back to the same finger. The swelling extended from the metacarpophalangeal joint to the proximal interphalangeal joint with restriction of terminal flexion at the joints. Plain radiographs revealed a lytic expansile lesion of proximal phalanx. There was no periosteal reaction, calcification in the matrix, or soft tissue involvement. MRI showed multiseptate T2 hyperintense lesion with fluid-fluid levels. Hemorrhagic fluid with granulation tissue was noted intraoperatively. Curettage and autologous iliac crest bone grafting were done. Histopathology confirmed the diagnosis of Aneurysmal bone cysts. At 12-month follow-up, the clinical swelling was absent and the radiograph shows good graft incorporation.

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