Mucinous appendiceal neoplasms with or without pseudomyxoma peritonei: a review

Mucinous appendiceal neoplasms (MANs) are rare tumours and the primary cause of pseudomyxoma peritonei. These tumours have a much more benign course than typical colorectal cancers, generally growing for many years before giving any clinical signs. The spectrum of presentations, tumour stages and the underlying cytology is very wide, warranting from the simplest operation like an appendicectomy to the most complicated operation like a complete cytoreduction surgery and hyperthermic intraperitoneal chemotherapy. Fortunately, most patients can be offered a curative treatment, but limiting operative morbidity without compromising oncologic outcomes is the biggest challenge in managing these patients. Histopathology is the cornerstone of decision making for MANs, but is also subject to ongoing debate because of a lack of terminology consensus amongst pathologists. Combined with the rarity of this disease, the multiple histopathologic classification updates of MANs explain the ongoing confusion amongst clinicians in regard to individual optimal treatment. This review will cover the most recent histological classification of MANs and attempt to clarify optimal management of patients with different clinical presentation and histologic combinations.