A Case of Endometrioid Adenocarcinoma Arising from Rectal Endometriosis

The paper reports a 70-year-old woman with bowel habit abnormalities and left lower abdominal pain in whom colonoscopy and pelvic CT/MRI revealed a 4×3 cm submucosal tumor–like lesion on the left side of the rectum. She underwent low anterior resection, and the resected specimen showed a submucosal mass with brown fluid and solid components; histopathology identified a well-differentiated adenocarcinoma infiltrating to the submucosal layer, with adjacent endometriosis in the rectal muscularis externa. Immunohistochemistry showed CD10 positivity in endometriosis stromal cells and cytokeratin 7 positivity with cytokeratin 20 negativity in the carcinoma cells, leading to a diagnosis of endometrioid adenocarcinoma arising from rectal endometriosis, and the authors note that malignant transformation of intestinal endometriosis is extremely rare and that immunostaining was useful for definitive diagnosis. This paper is centrally about endometriosis — it describes an endometrioid adenocarcinoma arising from rectal endometriosis.

Read from the paper's body, not the abstract. Not a substitute for reading the paper. No clinical advice. How this works