[Primary leiomyosarcoma of bone. Report of 5 anatomo-clinical cases and review of the literature].

INTRODUCTION

Leiomyosarcoma is a malignant smooth muscle tumor occurring most frequently in uterus or soft tissues and more rarely in bone.

MATERIALS AND METHODS

We report the clinicopathologic, immunohistochemical and ultrastructural findings of five cases of primary leiomyosarcoma of bone treated in our Department between 1991 and 1994. The pertinent medical literature is discussed.

RESULTS

The tumors were located respectively in the distal tibia (n=2), the distal femur, the sternum and the ilium (n=1). Four lesions were high-grade and one low-grade. All patients (3 women and 2 men) underwent wide surgical resection associated with polychemotherapy in four cases. Two patients died of metastatic disease, two had local recurrence and one is alive with no evidence of disease at the last follow-up.

DISCUSSION

Excluding cases which involve the facial skeleton, there are to our knowledge 95 cases of primary leiomyosarcoma of bone reported in the literature. This tumor arises more commonly in adults (mean age: 49 years) with an equal gender distribution and involves predominantly the long bones near the knee. In the majority of cases, plain X-rays exhibit an osteolytic lesion with cortical penetration and indistinct margins. The diagnosis is based on microscopic features demonstrating fusiform tumor cells arranged in interwoven bundles, and the immunohistochemical results of widespread cytoplasmic positivity for smooth muscle actin. The best pronostic parameter is the histologic grade correlated with both the recurrence and metastatic rates as well as the survival rate. Surgery constitutes the main treatment since chemotherapy or radiotherapy did not provide an improved prognosis over a wide resection.