Xanthogranulomatous Inflammatory Pelvic Mass Mimicking Malignancy: Successful Conservative Treatment and Narrative Insights into Diagnosis and Management.

Pelvic xanthogranulomatous inflammation is a rare pathological entity that can closely mimic malignant disease on cross-sectional imaging, often leading to consideration of radical surgical intervention. We report the case of a 59-year-old woman who presented with a large retrovesical pelvic mass initially suspected to be a malignant process. A definitive diagnosis was established only after tissue biopsy and comprehensive histopathological examination, which excluded malignancy and demonstrated xanthogranulomatous histiocytic inflammation. In light of the lesion's anatomical location and the substantial morbidity associated with surgical resection, a conservative medical strategy was pursued. Treatment with systemic corticosteroids and everolimus led to marked clinical improvement and a substantial radiological response, with reduction in lesion size from 41 × 26 mm to 27 × 17 mm, thereby allowing avoidance of mutilating surgery. This case underscores the critical role of biopsy and expert pathological assessment in guiding clinical decision-making and supports the consideration of non-surgical therapeutic approaches in selected patients with xanthogranulomatous pelvic lesions.