A Rare Case of Psoas Abscess Secondary to Mucinous Adenocarcinoma of the Appendix: A Case Report

INTRODUCTION: Iliacus and psoas muscles are located in an extraperitoneal location forming the iliopsoas compartment. Iliopsoas abscess is a myositis involving this compartment. Pseudomyxoma peritonei is characterized by an abundant extracellular collection of mucin in the peritoneal cavity. When this collection is retroperitoneal, it is termed as pseudomyxoma extraperitonei. We present to you the case of a 52-year-old female with psoas abscess secondary to mucinous adenocarcinoma of the appendix, which was later diagnosed as pseudomyxoma extraperitonei. CASE PRESENTATION: A 52-year-old female presented with pain in the right flank with discharging sinuses since one year. She had previously undergone two surgeries in the past 1 year for drainage of the abscess and had taken first line anti-tubercular treatment for around 6 months. She was managed in our institute by an open drainage of the abscess. The culture reports showed an infection with E. coli. The histopathology sections showed abundant pools of extracellular mucin with strips of columnar epithelium which indicated the pathology to be a mucinous adenocarcinoma. A contrast-enhanced computed tomography scan of the abdomen and pelvis showed a ruptured appendix mucocele and a collection in the right psoas muscle showing fistulous communication with the cecum and extending to the suture site in the right flank. Anti-tubercular treatment was stopped and an oncology opinion was taken. The patient was managed with a palliative ileostomy. CONCLUSION: It is important to keep in mind diagnostic possibilities other than tuberculosis of the spine when managing a patient with an iliopsoas abscess. These include pathologies of the gastrointestinal and genitourinary tract, which need to be diagnosed and managed early.