Gigantic lumbar aneurysmal bone cyst with abdominal extension in a pediatric patient: case report and its multidisciplinary management.

Background: Aneurysmal bone cyst (ABC) is a rare, benign, and highly vascular osteolytic lesion characterized by expansile cystic spaces filled with blood and surrounded by thinned cortical bone. ABC is most commonly found in the vertebral column, most specifically in the posterior element of the lumbar spine. Management of spinal ABCs poses a challenge to the treating physician given its proximity to the neural structures. Surgical intervention, radiation therapy, cryotherapy, and embolization are effective treatment methods. However, no treatment protocol has been established in the literature, particularly when the tumor is uncommonly large. Case Description: We present the case of a 12-year-old female with a flank mass and abdominal fullness, imaging showed a gigantic expansile lytic lesion with left sided extension to the visceral organs at the level of L4 with mild scoliotic deformity. A biopsy confirmed an ABC. Patient underwent embolization and sclerotherapy which failed to achieve tumor control. Patient was taken for anterior tumor intralesional excision with posterior instrumented fusion. Postoperatively patient symptoms, deformity and her overall alignment improved. Conclusions: The current case described the largest ABC spine tumor of the current pediatric literature. Multidisciplinary surgical management enabled satisfactory clinical and radiological outcomes with no recurrence at the last follow-up.