Presacral Neuroendocrine Tumor Treated With a Combined Robotic Dissection and Kraske Procedure: A Case Report

The presacral space, which includes the rectum anteriorly, the sacrum posteriorly, and the endopelvic fascia laterally, is an area of the body that rarely presents with masses. In addition, it is even more unusual to have neuroendocrine neoplasms (NENs) in that location. Presacral NENs typically behave as well-differentiated tumors with local involvement. Given the rarity of this disease, data on treatment outcomes are lacking. We present a case of a presacral NEN in a 63-year-old man with a right-sided buttock cyst measuring 13.7 x 9.4 x 8.3 cm. The mass was confirmed by imaging to be unilocular in the presacral soft tissues, extending into the right medial gluteal subcutaneous fat. No septation or nodular internal enhancement was seen to suggest malignant degeneration. No infiltration of adjacent structures was observed. He was treated using a combined robotically assisted laparoscopic excision of retrorectal cyst with posterior rectum mobilization and Kraske procedure. Nine months later, an adenocarcinoma in the pancreatic head and uncinate process was confirmed and treated. No recurrence of either cancer has been seen. This case is unique in that it involves an older man whose postoperative course is followed for 18 months, while most published cases of NEN occur in middle-aged women with little detail regarding follow-up care, subsequent metastasis, or systemic treatment. The majority of NEN cases have been treated with local resection, as in this case. When systemic therapy is necessary, somatostatin analogs have been used as an effective treatment for presacral NEN. The majority of tumors are nonfunctioning and somatostatin receptor positive. Extrapolating what is known for the other areas of gastrointestinal tract NEN, peptide receptor radionuclide therapy and tyrosine kinase have been tried with the former demonstrating promising activity and the latter warranting further investigations. Further prospective evaluation of this rare tumor entity is needed.