Clear cell carcinoma arising from abdominal wall endometriosis: A case report with imaging findings and pathologic...

Clear cell carcinoma arising from abdominal wall endometriosis is an exceptionally rare malignancy that typically develops at prior surgical scar sites. We report a case of a woman in her 50s with a history of cesarean section who presented with a gradually enlarging painful pubic mass. Ultrasound detected a lower abdominal wall mass, and contrast-enhanced CT and MRI demonstrated a subcutaneous lesion with mixed cystic and solid components abutting and extending into the rectus abdominis muscle; the solid component showed heterogeneous progressive enhancement and restricted diffusion with a minimum apparent diffusion coefficient of 0.401 × 10^-3 mm²/s. Biopsy and subsequent wide excision confirmed clear cell carcinoma arising in abdominal wall endometriosis, and no malignancy was identified in the uterus or adnexa. This case highlights that malignant transformation should be considered when a scar-related abdominal wall mass exhibits a cystic-solid architecture with restricted diffusion, and that ultrasound followed by cross-sectional imaging can facilitate assessment of local invasion and staging.