Author: Nat Pernick, M.D. (see Authors page)

Revised: 15 December 2015, last major update November 2011

Copyright: (c) 2002-2015,, Inc.

Cite this page: Smoothelin. website. Accessed October 28th, 2016.
Definition / General
  • Distinction of cytoplasmic from nuclear staining may be important
Uses by Pathologists
Micro Images

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Lamina propria: Muscularis mucosae (arrowhead); Detrusor muscle (arrow)

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Various images

Positive Staining - Normal
  • Differentiated smooth muscle cells
Positive Staining - Disease
  • Cytoplasmic staining: benign smooth muscle tumors, GI leiomyosarcomas (24%, Am J Surg Pathol 2009;33:1795
  • Nuclear staining: GI leiomyosarcomas (41%), GIST (22%)
Negative Staining
  • Striated muscle, myofibroblasts, myoepithelial cells, pericytes
  • Negative cytoplasmic staining in dedifferentiated liposarcoma, desmoid tumor, GIST, inflammatory myofibroblastic tumor, MPNST, schwannoma