Smooth muscle tumors of soft tissue and non-uterine viscera: biology and prognosis

Abstract

Smooth muscle tumors are here considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas. Soft tissue smooth muscle tumors with both atypia and mitotic activity are generally diagnosed leiomyosarcomas acknowledging potential for metastasis. However, lesions exist that cannot be comfortably placed in either category, and in such cases the designation 'smooth muscle tumor of uncertain biologic potential' is appropriate. The use of this category is often necessary with limited sampling, such as needle core biopsies. Benign smooth muscle tumors include smooth muscle hamartoma and angioleiomyoma. A specific category of leiomyomas are estrogen-receptor positive ones in women. These are similar to uterine leiomyomas and can occur anywhere in the abdomen and abdominal wall. Leiomyosarcomas can occur at any site, although are more frequent in the retroperitoneum and proximal extremities. They are recognized by likeness to smooth muscle cells but can undergo pleomorphic evolution ('dedifferentiation'). Presence of smooth muscle actin is nearly uniform and desmin-positivity usual. This and the lack of KIT expression separate leiomyosarcoma from GIST, an important problem in abdominal soft tissues. EBVassociated smooth muscle tumors are a specific subcategory occurring in AIDS or post-transplant patients. These tumors can have incomplete smooth muscle differentiation but show nuclear EBER as a diagnostic feature. In contrast to many other soft tissue tumors, genetics of smooth muscle tumors are poorly understood and such diagnostic testing is not yet generally applicable in this histogenetic group. Leiomyosarcomas are known to be genetically complex, often showing 'chaotic' karyotypes including aneuploidy or polyploidy, and no recurrent tumor-specific translocations have been detected.

Ulcerated gastric leiomyoma causing massive upper gastrointestinal bleeding: A case report

“…Leiomyomas tend to occur in younger patients compared with GISTs (7). Leiomyosarcomas are far less common and can be differentiated from leiomyomas by their very high mitotic rate (11).…”

Primary Small-Bowel Malignancy: Update in Tumor Biology, Markers, and Management Strategies

“…Unlike GIST, specific molecular therapy for leiomyosarcoma is lacking. GIST arises from interstitial cells of Cajal, while leiomysarcoma arises from denovo mutations in the smooth muscles of the gastrointestinal tract [67]. These tumors may present as intraluminal or extraluminal mass, reach giant sizes with bleeding, obstruction, and hemoperitoneum.…”

Lágyéksérvet utánzó gigantikus méretű myxoid leiomyoma

“…A parazita jelző arra utal, hogy feltételezések szerint ez a tumor kezdetben a méh-vel lehetett összeköttetésben, majd később levált róla. Mivel ez a teória teljességgel nem bizonyított, inkább peritonealis eredetű, hormonszenzitív simaizomtumorról beszélhetünk [3]. Ilyen típusú tumorok előfordulhat-nak a retroperitoneumban, ahol nagy méreteket ölthet-nek, de máshol is a szervezetben, például a peritoneumon, a csepleszen, mesenteriumon, belek között vagy intestinalis lokalizációban is.…”

“…Müller-cső-eredetű leiomyoma esetében az immunhisztokémiai vizsgálatok pozitív eredményt adnak SMA, desmin, caldesmon, ösztrogén, progeszteron és Wilmstumor-fehérje (WT1) kimutatása esetében [3]. Betegünknél ösztrogén-és WT1-pozitivitás volt kimutatható.…”