Primary well differentiated neuroendocrine tumor of ovary collides with Mucinous borderline tumor in a postmenopausal female: a report of case and review of literature.

Collision tumors represent a coexistence of two adjacent but histologically distinct tumors without histologic admixture in an organ. Primary well differentiated neuroendocrine tumor of ovary is rare and coexistent borderline mucinous tumor makes this association extremely rare. Although these tumors have been reported in other organs, its occurrence in ovary is rare. Collision tumor comprising primary neuroendocrine tumor of ovary and mucinous borderline tumor is an extremely rare occurrence. Here we report a case of this collision tumor in a postmenopausal female. H&E and immunohistochemical stains for chromogranin, synaptophysin, CDX-2, CK20, CK7 and Ki-67 were performed to confirm the diagnosis of collision tumor. Extensive search of literature revealed only a couple of cases report so far with this association. Our case is unique for a reason that we have reported trabecular variant of neuroendocrine tumor while the previously reported cases were insular variant. Management depends on patient's age, desire for fertility and disease distribution.