Metastasizing leiomyoma of the uterus S-phase fraction, estrogen receptor, and ultrastructure

Abstract

A 33-year-old woman had a metastasizing leiomyoma in which mitotic figures could not be found. The tumor was composed of well differentiated smooth muscle indistinguishable from uterine leiomyoma or normal myometrium by light and electron microscopy. The S-phase fraction of the tumor, measured by in vitro tritiated thymidine labeling, was near the upper limit of the range seen in seven ordinary uterine leiomyomas and was distinctly lower than that in a uterine leiomyosarcoma. The content of estrogen receptors in the cytosol was within the range seen in uterine leiomyomas. Metastasizing leiomyoma is an actively proliferating neoplasm of mature smooth muscle that appears to be hormonally responsive. The tumor in our patient showed no clear differences from ordinary leiomyomas in findings relating to the rate of cellular proliferation, morphology, or estrogen receptor content.

Benign metastasizing leiomyoma of the uterus: documentation of clinical, immunohistochemical and lectin-histochemical data of ten cases

“…In particular, 285 The pulmonary lesions have a benign morphology, which has led to the contradictory term 'benign metastasizing leiomyoma.' Several hypotheses on the histogenesis of these lesions have been suggested, which include a) Metastases of low grade and undetected sarcomas of the uterus [12,13,25,26] b) Lung emboli of cells from a benign leiomyoma of the uterus [7,14,23] c) Smooth muscle proliferation in various organs, such as the lungs and uterus, resulting from an abnormal sexual hormone status [5,15,16].…”

“…These cells usually have a benign appearance [11,26,38]. Mitoses are rare, necrosis is absent, and the inflammatory response of the host tissue is minimal [12,13,26,38]. The origin of the lesion continues to be controversial.…”

“…The origin of the lesion continues to be controversial. It may be a generalized leiomyomatosis mainly involving the uterus and the lungs [5,15,16], late metastases of an unrecognized well-differentiated leiomyosarcoma of the uterus [12,13,25,26], or benign uterine leiomyoma that embolizes to the lungs [7,14,23]. Indeed, some cases that have been reported tend to support the theory of a generalized leiomyomatous disease [9].…”

“…It refers to a type of lesion characterized by well-circumscribed, singular or, often, multiple nodules of proliferating smooth muscle cells in the lungs of women with a history of hysterectomy [36]. Such lesions have commonly been reported in young premenopausal women, whose resected uteri have displayed leiomyomatous alterations without any indication of malignancy [1,4,9,[11][12][13]26]. The nodules in the lungs are usually detected years after hysterectomy and are made up of benign-looking aggregates of smooth muscle cells with rather homogeneous nuclear size and volume rarely including mitotic figures [21][22][23][24][25][26]36].…”

Clinical benefit of endocrine therapy for benign metastasizing leiomyoma

“…Most included patient histories of uterine operations, including myomectomy and hysterectomy, suggesting a clue to the disease pathogenesis. While pulmonary lesions are known as the predominant metastatic sites [5,6], other sites, including skin, deep soft tissue, bones, skull, spine, muscle, and lymph nodes, have been described [7][8][9][10][11]. Most of the studies suggested that tumor cells of uterine myomas had spread to other organs via the blood vessels during various surgical procedures.…”