Pseudomyxoma retroperitonei secondary to appendiceal mucinous adenocarcinoma disguised as psoas abscess – A case report

Appendiceal cancers are rare tumors, with mucinous cystadenocarcinoma accounting for 58 % of malignant appendiceal tumors. Mucinous cystadenocarcinomas are typically low grade but may lead to pseudomyxoma peritonei, causing accumulation of gelatinous material in the abdomen, often referred to as ‘jelly belly’. In rare instances, the tumor may perforate into the retroperitoneal cavity leading to the phenomenon described as pseudomyxoma retroperitonei or extraperitonei. We describe the case of a young man presenting with a psoas abscess, initially treated with antibiotics. When the abscess failed to resolve, further testing was undertaken and revealed a diagnosis of mucinous adenocarcinoma with pseudomyxoma retroperitonei. The patient underwent a right hemicolectomy with debridement of the psoas abscess cavity. This case illustrates the need for a high index of suspicion for malignancy in the setting of recurrent or atypical psoas abscess. Appendiceal mucinous neoplasms are found in