[Pulmonary lymphangioleiomyomatosis. Immunohistochemical and ultrastructural study of two cases]

The authors report two cases of pulmonary lymphangioleiomyomatosis which were diagnosed by surgical biopsies. Immunohistochemical study showed positive staining of the smooth muscle cells using antibodies directed against smooth muscle actin, specific muscle actin, HMB45 and vimentin. Ultrastructural study showed some smooth muscle differentiation features, with numerous myofilaments and some dense bodies near the plasma membrane. In one case, the patient was treated by a double-lung transplantation. LAM is a non-familial disease occurring exclusively in females. The etiology is unknown. This disease can be complicated by chronic respiratory failure. Extrapulmonary sites are not rare, particularly in the uterus. Anti-estrogen treatment can slow the course of the disease. Lung transplantation is actually the only effective treatment at the present time therapy. The differential diagnosis of this disease is discussed.