A case of pure uterine lipoma: immunohistochemical and ultrastructural focus.

BACKGROUND: Pure uterine lipoma is a rare clinical event and only a few cases have been reported in literature. The histogenesis of these lesions is still debatable. Preoperative diagnosis is difficult and should be pathologically confirmed postoperatively. CASE: We report the case of a 58-year-old woman who presented with pelvic pain and postmenopausal uterine bleeding. The hysterectomy specimen showed a pure intramural lipoma of the uterus. An immunohistochemical study revealed that the lipomatous tissue was reactive to S-100, vimentin, actin and desmin. Electron microscopy examination revealed bundles of spindle cells with intracytoplasmatic vacuoles and parallel-arranged intermediate filaments in the surrounding zone, in which adipose cells were mixed with muscular cells. DISCUSSION: Clinical and histological diagnosis of pure uterine lipomas are described and a possible involvement of fatty metaplasia of smooth muscle cells in the development of pure uterine lipomas is discussed.