Metastatic Uterine Leiomyosarcoma to Bone: A Clinicopathologic Study

Abstract

Metastatic uterine leiomyosarcoma to bone is uncommon. We report the clinicopathologic findings from 4 cases, including examples with deceptively bland radiographic and/or histopathologic features. One case was remarkable in that both the multiple uterine smooth muscle tumors as well as the metastatic bone tumors appeared histologically benign, raising the question of its being a case of disseminated leiomyomatosis. Three patients presented with uterine disease with osseous metastases detected 1, 3, and 12 years later. One patient initially presented with neurologic findings due to a vertebral metastasis prior to detection of the uterine primary. A variety of radiographic patterns was seen, ranging from lytic destructive bone tumors to nonaggressive lesions with sclerotic margins. Most were mixed lytic/sclerotic tumors, and a soap bubble pattern was seen in a few. One tumor radiographically resembled giant cell tumor of bone. Microscopically, the bone metastases in 2 cases showed marked fibrosis and appeared much blander than the uterine primaries. Immunohistochemical reactivity for muscle-specific actin and smooth-muscle actin in both primary and metastatic tumors confirmed the diagnosis in these cases. Metastatic leiomyosarcoma to bone can present with a variety of radiographic patterns and with altered histology compared to the primary tumor. It can be mistaken for a primary bone tumor, benign or malignant. Awareness of these potential pitfalls combined with knowledge about the clinical history should prevent misdiagnosis and ensure proper management. Int J Surg Pathol 4(3):00-00, 1997