Extrapulmonary lymphangioleiomyomatosis (LAM) is a rare neoplasm of spindle cells exhibiting melanocytic and myoid differentiation that arises as a mass in the mediastinum, retroperitoneum, uterine wall, and/or intraperitoneal lymph nodes. Many patients also have pulmonary LAM, tuberous sclerosis complex (TSC), and/or other neoplasms of the perivascular epithelioid cell tumor family. This study reports 26 patients with clinically occult LAM involving pelvic/para-aortic lymph nodes removed from women undergoing surgical staging of a uterine (17), ovarian (5), cervical (3), or urinary bladder (1) neoplasm. None of the patients exhibited symptoms of pulmonary LAM, and the median patient age (56 y) was older than what would be expected for patients presenting with pulmonary LAM. Only 2/26 patients had TSC. Four patients also had uterine LAM. One of these 4 had uterine perivascular epithelioid cell tumor, and 1 had vaginal angiomyolipoma. In all 26 patients the lymph node LAM was grossly occult, measured 3.5 mm on average (1 to 19 mm), and involved either a single lymph node (12/26) or multiple lymph nodes (14/26). HMB45 was positive in 24/25 cases, mostly in a focal or patchy distribution. Other melanocytic markers included MiTF (12/14) and MelanA (2/12). Myoid markers included smooth muscle actin (23/23) and desmin (15/16), mostly in a diffuse distribution. Estrogen receptor was positive in all cases tested, as was D240 expression in the lymphatic endothelium lining the spindle cell bundles. Concurrent findings in the involved lymph nodes included metastatic carcinoma (3/26), endosalpingiosis (3/26), and reactive lymphoid hyperplasia (13/26). This study demonstrates that clinically occult lymph node LAM can be detected during surgical staging of pelvic cancer and is not commonly associated with pulmonary LAM or TSC, although these patients should still be formally evaluated for both of these diseases.
*Department of Pathology, University of California San Francisco, San Francisco
†Department of Pathology, El Camino Hospital, Mountain View, CA
‡Department of Pathology, University of Colorado, Denver, CO
Presented in part at the 2012 Annual Meeting of the United States and Canadian Academy of Pathology.
Conflicts of Interest and Source of Funding: Support was received from the University of California San Francisco Department of Pathology Resident Teaching Research Endowment. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.
Correspondence: Joseph T. Rabban, MD, MPH, Department of Pathology, University of California San Francisco, 505 Parnassus Avenue, M552, San Francisco, CA 94143 (e-mail: email@example.com).