Low-grade fibrosarcoma (hyalinizing spindle cell tumor with giant rosettes) with pulmonary metastases at presentation: case report and review of the literature.

Hyalinizing spindle cell tumor with giant rosettes (HSCT) is presently considered a low-grade fibrosarcoma and is also considered a variant of low-grade fibromyxoid sarcoma by some. None of the HSCTs in the original series had manifested malignant behavior in the form of metastasis, but since that initial report, 2 patients have been reported with pulmonary metastases and another patient with multiple pulmonary nodules in the absence of an identifiable primary tumor. Our patient is the second recorded case of HSCT with pulmonary metastases at the time of diagnosis. A needle biopsy of the axillary mass in the present case consisted mainly of densely hyalinized collagen, whereas the lung nodules had the characteristic giant collagen rosettes surrounded by a bland spindle cell stroma. This case, in addition to at least 2 others in the literature, has demonstrated that the HSCT is a malignant neoplasm with the capacity to metastasize; however, the presence and even persistence of metastatic lesions in the lung has not altered to date an otherwise indolent clinical course. The fact should not be overlooked that the HSCT is a recently reported entity whose natural history and nosology are subjects of continuing observation, study, and discussion.