Expression of desmin and smooth muscle myosin heavy chain in dermatofibromas.

Abstract

BACKGROUND:

The histopathologic features of dermatofibroma vary remarkably, and this diversity may occasionally cause problems in differentiating between benign and malignant mesenchymal lesions, including smooth muscle neoplasms. Immunohistochemical stains are sometimes necessary to clarify the histogenesis of a lesion.

OBJECTIVE:

To evaluate dermatofibromas for expression of desmin and smooth muscle myosin heavy chain (SM-MHC) antigens, which are commonly used as evidence of smooth muscle differentiation.

METHODS:

We studied 100 consecutive cases of dermatofibroma using hematoxylin-eosin-stained sections and immunoperoxidase staining with antibodies against desmin, SM-MHC, and smooth muscle actin.

RESULTS:

We found focal positivity for desmin in 9 cases, and in 2 of these cases, at least 10% of lesional cells showed strong expression. We found focal staining for SM-MHC in 10 cases, and in 2 of these cases, at least 10% of the lesional cells were positive. Regions positive for desmin and/or SM-MHC did not show definite histologic features of myogenous differentiation on hematoxylin-eosin-stained sections. All dermatofibromas expressing desmin and SM-MHC were also strongly positive for smooth muscle actin.

CONCLUSIONS:

About 10% of dermatofibromas show focal expression of desmin and SM-MHC, and this expression may be present in up to 10% to 15% of lesional cells. Thus, in dermal spindle cell lesions, focal expression of these muscle antigens, like that of smooth muscle actin, is not diagnostic of a smooth muscle tumor.

• Authors: Andrea K Bruecks, Martin J Trotter
• Journal: Archives of pathology & laboratory medicine (Arch Pathol Lab Med) Vol. 126 Issue 10 Pg. 1179-83 (Oct 2002) ISSN: 0003-9985 [Print] United States
• PMID: 12296754 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Actins
• Desmin
• Smooth Muscle Myosins
• Myosin Heavy Chains

Topics

• Actins (metabolism)
• Adult
• Aged
• Cell Count
• Desmin (metabolism)
• Female
• Histiocytoma, Benign Fibrous (metabolism, pathology)
• Humans
• Immunoenzyme Techniques
• Leiomyoma (metabolism, pathology)
• Male
• Middle Aged
• Myosin Heavy Chains (metabolism)
• Skin Neoplasms (metabolism, pathology)
• Smooth Muscle Myosins (metabolism)