Skin nonmelanocytic tumor
Cutaneous muscle tumors & hamartomas
Atypical smooth muscle tumor
Author: Christopher S. Hale, M.D.
Last author update: 1 September 2012
Last staff update: 8 September 2023
Copyright: 2001-2024, PathologyOutlines.com, Inc.
PubMed Search: Atypical smooth muscle tumor skin
Table of Contents
Definition / general | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Differential diagnosisCite this page: Hale C. Atypical smooth muscle tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticLMS.html. Accessed December 2nd, 2024.
Definition / general
- Superficial dermal based smooth muscle tumor which is biologically different from deep leiomyosarcoma
- Typically larger than leiomyomas with vascular invasion
- Recurs, but only rarely metastasizes
- May be associated with HIV infection
Case reports
- 59 year old woman with painless skin nodule (J Med Case Reports 2007;1:180)
- 67 year old woman with neck lesion (Cases J 2010;3:52)
Microscopic (histologic) description
- Cellular lesions of smooth muscle type cells with atypia, necrosis and mitotic activity
- May have prominent vascular pattern, clear cell features, desmoplasia
Microscopic (histologic) images
Images hosted on other servers:
Subcutaneous spindle cell neoplasm
Spindle cells and osteoclast-like giant cells
SMA+ and CD68+
Positive stains
- HHF35 (90%), alpha smooth muscle actin (90%), vimentin, desmin (75%) (Cancer 2009;115:4186)
Differential diagnosis
