Pubic Aneurysmal Bone Cyst Following Penile Inversion Vaginoplasty: A Case Report.

Background: Aneurysmal bone cysts (ABCs) are aggressive, expansile, and locally destructive vascular lesions. The exact etiology of ABCs is currently unknown and hypothesized to be related to vascular malformations or disruption of osseous vascularity. To date, there have been no reports describing the development of pubic ABCs following penile inversion vaginoplasty (PIV). Methods: This report describes the development of a pubic ABC in a transgender patient who had previously undergone PIV, possibly indicating a very rare complication of this gender-affirming operation. Results: A 37-year-old transgender female was initially referred to the orthopedic oncology clinic for evaluation of a 12-month history of left hip and groin pain. She had undergone gender-affirming PIV about 19 months prior to presentation. Magnetic resonance imaging (MRI) with contrast revealed a low T1 signal intensity and heterogenous T2 hyperintensity 7.5 × 4.9 × 4.3-cm destructive mass in the left superior pubic ramus extending across the pubic symphysis into the right superior pubic ramus. A needle core bone biopsy demonstrated a variably cellular spindle and round lesion with islands of osteoid formation and focal necrosis. The cells were negative for CD34, S100, and desmin. There was no evidence suggesting osteosarcoma, and final review favored the diagnosis of an ABC. Given the highly destructive nature of the mass, it was resected, and the resulting wound was reconstructed with a biologic dermal mesh. Conclusions: Although it is impossible to distinguish coincidence from causation in this case, the patient's recency of PIV and development of a rare ABC in a nearby bone warrants the speculation and discussion provided in this report.