Metastases to the retroperitoneum in patients with extremity soft tissue sarcoma: an unusual metastatic pattern

Extremity soft tissue sarcoma (STS) metastasizes preferentially to the lungs via the hematogenous route. Metastases in extrapulmonary sites such as bone, brain, and subcutaneous tissues are observed less frequently. To the authors' knowledge, limb STS primarily metastasizing to the retroperitoneum has not been described to date. The current study reviews the clinical course, management, and patient prognosis in such a pattern of metastasis.

Records of patients with retroperitoneal metastases originating from an extremity STS between 1994-1998 were reviewed. Patient demographics, primary tumor site, other tumor sites, local recurrence, distant metastasis, treatment, and survival were analyzed.

Ten patients were included in the study. All had primary STS of different histologic types and high histologic grade confined to a lower limb. The retroperitoneal metastases were diagnosed between 6-120 months (mean, 45 months) after diagnosis of the primary sarcoma. At that time, one patient had evidence of local recurrence of the primary tumor site, two patients had lung metastases, and one patient had diffuse bone metastases. Eight patients were eligible for surgery. In six of these patients the metastases were excised completely. The median follow up was 12 months. Of the six patients who underwent complete resection, 3 were alive at last follow-up with no evidence of disease after 12 months, 14 months, and 24 months, respectively. Two patients with recurrent retroperitoneal disease and one patient with retroperitoneal and lung metastases died despite systemic chemotherapy.

Extremity STS can metastasize hematogenously to the retroperitoneum, a fact that mandates a high index of suspicion and abdominal imaging studies during the follow-up of such patients. Retroperitoneal metastases necessitate aggressive surgical resection to enable prolongation of survival.