Image Description
The plump myoid cells in lymphangiomyomatosis are positive for HMB-45, melan A, beta-catenin, and smooth muscle actin. Many cases stain for estrogen and progesterone receptors. They are usually negative for S-100 protein.
The image shows lesional spindle-shaped myoid cells around the edges of cystic airspaces.
About the Disease
PEComatous tumors arise from perivascular epithelioid cells and can present in the lung in following forms: 1) Lymphangiomyomatosis; 2) Clear cell sugar tumor of lung; 3) PEComatosis with overlapping features between lymphangiomyomatosis and PEComa. Other tumors in this family include renal and extrarenal angiomyolipoma, primary extrapulmonary sugar tumor, clear cell myomelanocytic tumor, and abdominopelvic sarcoma of perivascular epithelioid cells. PEComatous tumors arise in a variety of sites and are tied together through their association with the tuberous sclerosis complex (and the mutations in tuberous sclerosis genes TSC1 and TSC2). References:Goldblum, J.R., Folpe, A.L., Weiss, S.L. (2014). Enzinger & Weisss Soft Tissue Tumors, 6th Ed. Philadelphia, PA: Elsevier Saunders. Travis, W.D., et al. (2015). WHO Classification of Tumors of the Lung, Pleura, Thymus and Heart, 4th Ed. IARC: Lyon, France.