Hypofractionated Stereotactic Radiation Therapy for Metastatic Adenocarcinoma ex Goblet Cell Carcinoid of the Appendix: Case Report and Literature Review.

Adenocarcinoma ex-goblet carcinoid (ADA ex-GCC) is a rare and aggressive subtype of goblet cell carcinoid, a distinct tumor of the appendix characterized by both neuroendocrine and glandular differentiation. Patients often present with chronic abdominal pain or symptoms of acute appendicitis. Right hemicolectomy is the primary mode of treatment, and prophylactic salpingo-oophorectomy and hysterectomy is recommended in post-menopausal women due to the tumor's propensity of transcoelemic spread, especially to the ovaries. In this case report, we describe a patient with ADA ex-GCC who was found to have oligometastic disease in the pelvis and treated with hypofractionated stereotactic body radiation therapy (HSRT). She initially underwent a right hemicolectomy followed by adjuvant capecitabine four years prior when her tumor was incidentally discovered on colonoscopy. She subsequently had a salpingo-oophorectomy for gynecologic tract metastatic disease and declined further chemotherapy. The patient was again discovered to have oligometastatic disease in the right pelvis adjacent to the rectum on a Gallium-68 dotatate PET/MRI, and was subsequently treated with HSRT to 39 Gy in 6.5 Gy daily fractions. The patient tolerated her radiation course without notable radiation-related toxicity, and she remains without disease progression nine months later.