title: Extrapulmonary lymphangioleiomyomatosis (LAM): clinicopathologic features in 22 cases.
abstract: We describe the lesions of extrapulmonary lymphangioleiomyomatosis (LAM) affecting the lymph nodes of the mediastinum and retroperitoneum in 22 women (mean age +/- SD, 42.4+/-10.5 years). In most of these patients, the diagnosis of extrapulmonary LAM preceded that of pulmonary LAM, usually by 1 to 2 years. Eleven patients had distinct symptoms, including chylous pleural effusion and/or ascites, abdominal pain, and palpable abdominal masses. In the other 11 patients, the masses caused no symptoms. Well-circumscribed, encapsulated masses, measuring up to 20 cm in size, occurred in the mediastinum in 2 patients, the upper retroperitoneum in 15, extensive areas of the retroperitoneum in 2, and the pelvis in 3. The masses exceeding 3 cm in diameter contained large, multiple cysts filled with yellow-tan chylous fluid. Histologically, the masses were characterized by a proliferation of smooth muscle cells (LAM cells) arranged in fascicular, trabecular, and papillary patterns, which were associated with slit-like vascular channels. The LAM cells varied from small, spindle-shaped cells to large epithelioid cells. Immunohistochemical studies showed a strong reactivity of most LAM cells for alpha-smooth muscle actin and smooth muscle myosin heavy chain and a weak to moderate reactivity of a lesser number of cells for desmin and nonmuscle myosin heavy chain II-B. A reaction for HMB-45 and estrogen and progesterone receptors was observed mainly in epithelioid LAM cells. These patterns of reactivity are similar to those observed in pulmonary LAM. However, the chylous cysts are not a feature of pulmonary LAM and are thought to result from obstruction of lymphatics.
authors.affiliation: Pathology Section and Pulmonary-Critical Care Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1518, USA.
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: A
authors.initials: A
authors.lastname: Tatsuguchi
authors.forename: J
authors.initials: J
authors.lastname: Valencia
authors.forename: Z x
authors.initials: Zx
authors.lastname: Yu
authors.forename: J
authors.initials: J
authors.lastname: Bechtle
authors.forename: M B
authors.initials: MB
authors.lastname: Beasley
authors.forename: N
authors.initials: N
authors.lastname: Avila
authors.forename: W D
authors.initials: WD
authors.lastname: Travis
authors.forename: J
authors.initials: J
authors.lastname: Moss
authors.forename: V J
authors.initials: VJ
authors.lastname: Ferrans
mesh_terms: D000199:Actins / Q000032:analysis; D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D005260:Female; D006801:Humans; D018192:Lymphangioleiomyomatosis / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D008875:Middle Aged; D018995:Myosin Heavy Chains / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis
chemical_list: D000199:Actins; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D018995:Myosin Heavy Chains