Collision tumors represent the coexistence of two or three adjacent but histologically distinct tumors, without histoiogic admixture in an organ. Collision tumors have been reported in various organs, but are rarely seen in the ovaries. Reported cases consisted of a benign mature ovarian teratoma and an ovarian cystadenoma or cystadenocarcinoma. Primary carcinoid tumors of the ovary, on the other hand, are uncommon, with a reported incidence of 0.3%. They are usually unilateral and are found in association with mature cystic teratoma, forming a solid nodule within it. Primary ovarian carcinoids rarely metastasize and are treated as ovarian tumors with low malignant potential. This is a rare case of a triple collision tumor of the ovary in a 63 year old multigravid who complained of a gradually enlarging abdominal mass. Total abdominal hysterectomy with bilateral salpingo oophorectomy and complete surgical staging was performed. Histopathology revealed coexistence of a mucinous tumor of low malignant potential, trabeculartype carcinoid tumor, and mature cystic teratoma in the right ovary. The possibility of the occurrence of such collision tumors must always be kept in mind intraoperatively and during pathologic examination to avoid misdiagnosis of these cases.

Human ; Female ; Middle Aged ; Diagnostic Errors ; Incidence ; Salpingo-oophorectomy ; Ovarian Germ Cell Cancer ; Ovarian Neoplasms ; Neoplasms, Glandular And Epithelial ; Teratoma ; Carcinoid Tumor ; Cystadenocarcinoma ; Cystadenoma ; Hysterectomy