Neuroendocrine Tumour Arising in a Retrorectal Dermoid Cyst

Abstract

Retrorectal dermoid cysts are rare congenital lesions but those with malignant degeneration are extremely unusual. The purpose of the poster is to allow doctors to share information about the investigation and treatment of this uncommon and difficult for surgery condition and to stress the attention on the probability of malignancy in retrorectal cysts in adults. To establish the diagnosis and to prevent complication, a total radical resection is recommended. Here, we are reporting, for the first time, the clinicopathological features and treatment of a neuroendocine cell tumour that arose in a retrorectal dermoid cyst.Case Report: A 45-year-old woman was hospitalized at our surgical department with confirmed retrorectal presacral multilocular cystic mass by CT and MRI. She complained of rectal pain and fullness, change in stool calibre and urinary frequency. There was not a history of rectal bleeding.CT and MRI scans of the abdomen and pelvic region revealed a cystic multilocular mass, with a size of 125/83mm in the rectrorectal presacral space, pressing but not invading the rectal walls. There were no signs of any secondary lesions in the lungs and the liver. Rectal US was not preformed. The patient underwent a laparotomy. Total cyst excision was performed with adnexectomy and hysterectomy. Because of great technical difficulties during the extirpation of the tumor, an iatrogenic lesion of the rectal wall was done. It was sutured with interrupted absorbable stitches. The operation was accomplished with a virtual colostomy. The pathological conclusion of the specimen was a dermoid cyst, sized 150mm/90mm, lined by stratified squamous epithelium with dermal appendages, chronically inflamed fibrous tissue and a solid component, where neuroendocrine neoplasm NET-G2 was identified. The immunohistochemical tests revealed a diffuse positive immunoexpression to Chromogranin, Synaptophysin, Vimentin, EMA, focal positive expression to HMW/CK and negative reaction to S100, GFAP, Desmin; proliferating index Ki67 - 13.1%.The patient had an uneventful hospital course and the virtual colostomy was not used. The woman was discharged 10 days later, on May 18, 2016. The oncological committee did not recommend neither radiotherapy nor chemotherapy. The follow-up visits will reveal if there are any recurrences in the future