Primary malignant tumors of the iliopsoas compartment

Primary malignant tumors of the iliopsoas compartment are rare entities that have been infrequently reported. We present our experience of iliopsoas malignancy to better characterize and define the natural history of this condition.

Primary iliopsoas tumors occurring from January 1990 were identified from the Royal Marsden Hospital's (RMH) Sarcoma Unit prospective database.

Nineteen malignant tumors (11 limited to the psoas muscle only, 1 involving only the iliacus muscle and 7 involving both the iliacus and psoas) of the iliopsoas compartment were evaluated and treated at the RMH during this period. Leiomyosarcoma (n = 5) and liposarcoma (n = 3) were the most frequent histologic types. There were 3 G1, 5 G2, 10 G3 tumors and grade could not be assessed in 1 patient. There were 17 T2 tumors and size was not available in 2 patients. Surgery was done in 14 patients (negative microscopic margins-7, positive microscopic margins-3, and positive gross margins-3 and the margin of excision was not known in 1 patient). Five of 14 surgically treated patients had local recurrence and 6 of 19 patients developed metastases. Ten patients died of their disease at a median follow-up of 12 months. The estimated 2 and 5 year survival rates were 44 and 23%, respectively.

Tumors in this location have a poor prognosis due to the lack of early diagnosis, large size at presentation, multiple attachments of the psoas muscle, and being relatively surgically inaccessible.