Collision tumor of the appendix with concomitant cecal adenocarcinoma: A case report and literature review.

Introduction: Collision tumors of the appendix are rare tumors consisting of two distinct pathologies arising from different cell lines simultaneously. The most common type is the coexistence of a neuroendocrine tumor (NET) with a low-grade appendiceal mucinous neoplasm (LAMN). We report a unique case of appendiceal collision tumor with synchronous cecal intra-mucosal carcinoma and pulmonary sarcoidosis.