Mucinous appendiceal neoplasms are uncommon, but important to recognize with imaging due to malignant potential. Peritoneal seeding and pseudomyxoma peritonei can occur with both frankly malignant as well as low-grade appendiceal neoplasms. Prospective imaging identification of potential appendiceal neoplasm is paramount to clinical/surgical management. When a mucinous appendiceal neoplasm is suspected, a right hemicolectomy with lymph node dissection is the preferred surgical management. Unfortunately, accurate preoperative diagnosis can be challenging due to a wide range of clinical presentations and overlapping imaging appearances of appendiceal neoplasms with benign entities. Using the 2010 World Health Organization (WHO) pathologic classification as a framework, we provide a comprehensive multi-modality pictorial essay detailing the broad array of imaging findings of mucinous appendiceal neoplasms and common imaging mimics.