Pediatric aneurysmal bone cyst in the ischial region.

Aneurysmal bone cyst (ABC) is an expanding osteolytic lesion. ABC represents 1% of all primary benign bone tumors, whereby 4-12% occur in the pelvis. The etiology of this disease remains vague. Aneurysmal bone cyst can exist either as primary bone lesion (70%) or as secondary lesion arising from another bone disorder (30%). Moreover, pelvic ABCs are characterized by their large size and high vascularity. We present a rare pediatric case with ABC involving the ischial region. A 5-year-old girl presented with left pelvic pain and limping for the past 6 months. Initial imaging showed an expansile lesion in the left ischium, and computed tomography guided biopsy showed giant cells in histopathology study with no evidence of metastasis. The patient underwent intraoperative frozen section followed by extensive intra-lesional bone excision. Bone curettage was pursued along with bone grafting. The case was successfully managed without postoperative complications after the 6-month follow-up period.