Lymphangioleiomyomatosis. A case report with an immunohistochemical study.

A case of pulmonary lymphangioleiomyomatosis is presented, which occurred in a 50-year-old woman suffering from severe dyspnea of 7 year's duration and with a previous history of diseases (polycystic ovaries and endometrial adenocarcinoma) usually related to hyperestrogenism. The patient showed no signs or symptoms of tuberous sclerosis, a condition often associated with pulmonary lymphangioleiomyomatosis. Both the radiological pattern and histological findings had previously been interpreted at other hospitals as consistent with either nodular interstitial fibrosis with emphysematous changes or pulmonary siderosis. Correct diagnosis was suspected on critical review of histological slides and definitely achieved by immunohistochemistry in routine sections, which showed the presence of desmin in the elements constituting the nodular lesions scattered throughout the parenchyma. The criteria for the differential diagnosis are discussed, as well as the role of immunohistochemistry in assessing the muscular nature of proliferating cells.