Rhabdomyosarcoma of the Iliopsoas: A Retroperitoneal Misdiagnosis.

Rhabdomyosarcoma (RMS) is a rare soft tissue sarcoma. The already documented data regarding RMS state that it is more prevalent in males than females and also that its occurrence is more in Caucasians than Asians. The current incidence of RMS is 4.5 cases/million, and thus, it is a very rare cancer. The undifferentiated type is the most aggressive one with a rare presentation in the retroperitoneum. Overall, this case emphasizes that consideration should be given to wide range of diagnosis and that frozen section is the gold standard for a confirmatory diagnosis, as the first biopsy showed benign cells within the tumor. The emphasis on the interventions related to imaging to prevent the chance of aggravated presentation in the terminal stage of somatic comorbidities like loss of power. Radical excision of the mass along with normal iliopsoas tendon was done and referred to a cancer specialty center for further chemotherapy. To the best of my knowledge, this is the only case of RMS of the iliopsoas.