Endometrioid adenocarcinoma in the lower rectum

Fewer than 50 cases of intestinal tumours associated with endometriosis have been reported, with endometrioid adeno - carcinoma being the commonest variant. Most cases occur in postmenopausal women receiving estrogen therapy following hysterectomy and double annexectomy for endometriosis. The clinical picture usually presents with abdominal pain, metror - rhagia and/or rectorrhagia (3). Tumours are usually found in the sigmoid colon, upper rectum, and rectovaginal septum, being exceptional in the extraperitoneal mid-lower rectum. The etiopathogenesis is unknown, and in most cases endo - metriotic implants are secondary to retrograde menstruation (4). Hyperestrogenism is a potential risk factor (5), and genetic pre- disposition is suggested for cases without it (5). On the other hand, the neurological hypothesis described by Possover and Anaf (6,7) correlates endometriotic implants with sympathetic nervous system distribution; this might account for our patient’s case since the mid-lower rectum’s location is extraperitoneal and in intimate contact with the sympathetic plexus. This case meets all the histological criteria defined by Samp- son (8) for endometrioid adenocarcinoma, with tumour cells growing from endometriotic foci within the rectal muscularis coat, hence not from invasion from the uterus. Furthermore, the histology of the hysterectomy specimen confirms uterine infil - tration by contiguity from the rectum, with no endometriotic sites in the uterus or annexes, and an endometrium with normal characteristics, which rules out a uterine origin. There is no consensus protocol regarding the treatment of choice. At any rate, the need for radical resection of the involved intestinal segment plus hysterectomy and double annexectomy is indisputable. Adjuvant therapy is warranted by the presence of nodal metastases and uterine infiltration. To conclude, endometrioid adenocarcinoma of the rectum is a rare tumour that requires a high index of suspicion for diagnosis. Importantly, it should be differentiated from colorectal tumours in order to optimize management and for its prognostic value. Our case is atypical in terms of age at presentation, absence of relevant history, and tumour location. Yurena Caballero1, Ángel Turégano1, Eudaldo López- Tomassetti1, María Soledad Martínez2, Virginia Benito3 and Juan Ramón Hernández1 Departments of 1General and Digestive Surgery, and 2Pathology. Hospital Universitario Insular de Gran Canaria. Las Palmas de Gran Canaria, Spain. 3Department of Oncological Gynecology. Hospital Universitario Materno Infantil de Gran Canaria. Las Palmas de Gran Canaria, Spain

1. Petersen VC, Underwood J, Wells M, Sheperd N. Primary endometroid adenocarcinoma of the large intestine arising in colorectal anastomosis. Histhopathology 2002;40:171-6. 2. Heaps JM, Nieberg RK, Berek JS. Malignant neoplasm arising in endo- metriosis. Obstet Gynecol 1990;75:1023-8. 3. Yantiss RK, Clement PB, Young RH. Neoplastic and pre-neoplastic changes in gastrointestinal endometriosis: A study of 17 cases. Am J Surg Pathol 2000;24:513-24. 4. Bouhmidi A, Sánchez Torres A, Martínez Jiménez T, Sáez Macia R, Sánchez de la Villa G, Montes Clavero C. Rectosigmoid endometriosis. Rev Esp Enferm Dig 2006;98:797-8. 5. Zanetta GM, Webb MJ, Li H, Keeney GL. Hyperestrogenism: A rel - evant risk factor for the development of cancer from endometriosis. Gynecol Oncol 2000;79:18-22. 6. Possover M, Rhiem K, Chiantera V . The “neurologic hypothesis”: A new concept in the pathogenesis if the endometriosis? Gynecol Surgery 2005;2:107-11. 7. Anaf V , El Nakadi I, Simon P, Van de Stadt J, Fayt I, Simonart T, et al. Preferential infiltration of the large bowel endometriosis along the nerves of the colon. Hum Reprod 2004;19:996-1002. 8. Sampson JA. Endometrial carcinoma of the ovary arising in endome- trial tissue in that organ. Arch Surg 1925;10:1-72.