FINAL DIAGNOSIS: LEIOMYOMAS
Leiomyomas are benign smooth muscle tumors common to the uterine myometrium where they are frequently multiple (1). Their etiology in the uterus is unknown, but hormonal influences (estrogen and progesterone), growth factors, and a wide range of chromosomal aberrations have been linked to tumorigenesis and growth (2). Outside of the uterus, leiomyomas have been reported in almost every organ in the body where they arise within vascular, glandular, respiratory tract and gastrointestinal smooth muscle (1). In the nervous system they have been reported as both dural-based or parenchymal masses where radiographically and histologically they can resemble schwannomas or meningiomas (3,4).
Leiomyomas were recently added to the list of neoplasms showing increased incidence in Acquired Immunodeficiency Syndrome (AIDS). The list also includes Kaposi's sarcoma, non-Hodgkin's lymphoma (NHL), primary central nervous system lymphoma (PCNSL), anal carcinoma, and cervical carcinoma (5). Human immunodeficiency virus (HIV) has not itself been directly linked to tumorigenesis in these HIV-related tumors, but other viruses have been identified in most of the tumors listed including, human herpes virus 8 in Kaposi's sarcoma, Epstein Barr virus (EBV) in NHL and PCNSL, human papilloma virus in anal and cervical carcinoma, and, recently, EBV in leiomyoma (6). Although immunosuppression represents the permissive environment that enables the viruses to express their tumor promoting capabilities, their role in actual tumorigenesis is, in some studies, questioned and a role for predominantly tumor growth is suggested (7). Research continues to determine the role these viruses play in tumorigenesis and tumor growth.
Contributed by: Nancy C. Karpinski, M.D., Reza Yaghmai, M.D., Ph.D., David Barba, M.D., Lawrence A. Hansen, M.D.