Malignant Psoas abscess or pseudomyxoma extraperitonei.

Primary adenocarcinoma of appendix is an uncommon gastrointestinal malignancy. Similarly, Psoas abscess is an entity, which sometimes requires extensive work-up to reach a diagnosis. Combined presentation of these two rare conditions is not only exceptional, but also diagnostically challenging. We present a case of a lady who presented with recurrent UTI secondary to right sided ureteric obstruction, referred right hip joint pain resulting from a Psoas abscess, which eventually turned out to be a consequence of metastatic adenocarcinoma of appendix, causing pseudomyxoma extraperitonei, with simultaneous intraperitoneal deposits.