Adenocarcinoma Ex-Goblet Cell Carcinoid of the Appendix With Metastatic Peritoneal Spread to Meckel's Diverticulum and Endometriosis.

Adenocarcinoma ex-goblet cell carcinoid is a very rare and histologically unique appendiceal malignancy with dual glandular and neuroendocrine differentiation. There is a high incidence of this tumor among middle-aged women with metastasis to the gynecologic tract with the mode of metastasis following peritoneal spread rather than hematogenous distribution. Adenocarcinoma ex-goblet cell carcinoid can spread to any peritoneal site including ovaries or omentum. We report a 37-year-old healthy woman who initially presented with right lower quadrant abdominal pain and pseudomyxoma peritonei. Histopathology of the appendectomy specimen revealed an adenocarcinoma ex-goblet cell carcinoid, signet ring cell type. Follow-up right hemicolectomy, omentectomy, bilateral salpingo-oophorectomy, and regional peritoneal resections revealed metastatic involvement by adenocarcinoma ex-goblet cell carcinoid, signet ring cell type. In this report, we describe a case of appendiceal adenocarcinoma ex goblet cell carcinoid with metastases to Meckel's diverticulum and areas of pelvic endometriosis, which have not been previously reported.