BACKGROUND: An existing problem in contemporary pathology is the classification and distinction of spindle cell soft tissue tumors of the skin. Markers such as alpha-smooth muscle actin (alpha-SMA) and desmin, considered specific for smooth muscle cell (SMC), have been shown to be expressed in a variety of fibroblastic and myofibroblastic processes. High-molecular-weight caldesmon (h-caldesmon), one of two isoforms, is reported to be expressed exclusively by SMC and has recently been shown to be a specific marker of SMC tumors. METHODS: Tumors were obtained from 11 patients taken from the surgical pathology archives of the University of South Florida and cases were coded as smooth muscle hamartoma, myofibroma, and dermatomyofibroma. RESULTS: The case of smooth muscle hamartoma had greater than 90% of tumor cells labeling with anti-h-caldesmon antibodies. Three of three cases of myofibroma had focal areas of positivity representing less than 10% of total tumor cells. Seven of seven dermatomyofibromas showed no apparent labeling with anti-h-caldesmon antibody. Dense reactivity was noted in vascular wall smooth muscle, indicating internal controls. CONCLUSIONS: We can conclude that h-caldesmon is a specific marker of fully differentiated smooth muscle and that it can serve to differentiate spindled SMC soft tissue tumors of the skin from tumors of myofibroblastic and/or fibroblastic origin.
BACKGROUND: An existing problem in contemporary pathology is the classification and distinction of spindle cell soft tissue tumors of the skin. Markers such as alpha-smooth muscle actin (alpha-SMA) and desmin, considered specific for smooth muscle cell (SMC), have been shown to be expressed in a variety of fibroblastic and myofibroblastic processes. High-molecular-weight caldesmon (h-caldesmon), one of two isoforms, is reported to be expressed exclusively by SMC and has recently been shown to be a specific marker of SMC tumors. METHODS:Tumors were obtained from 11 patients taken from the surgical pathology archives of the University of South Florida and cases were coded as smooth muscle hamartoma, myofibroma, and dermatomyofibroma. RESULTS: The case of smooth muscle hamartoma had greater than 90% of tumor cells labeling with anti-h-caldesmon antibodies. Three of three cases of myofibroma had focal areas of positivity representing less than 10% of total tumor cells. Seven of seven dermatomyofibromas showed no apparent labeling with anti-h-caldesmon antibody. Dense reactivity was noted in vascular wall smooth muscle, indicating internal controls. CONCLUSIONS: We can conclude that h-caldesmon is a specific marker of fully differentiated smooth muscle and that it can serve to differentiate spindled SMC soft tissue tumors of the skin from tumors of myofibroblastic and/or fibroblastic origin.
Authors: Ryotaro Hashizume; Kazuro L Fujimoto; Yi Hong; Nicholas J Amoroso; Kimimasa Tobita; Toshio Miki; Bradley B Keller; Michael S Sacks; William R Wagner Journal: Biomaterials Date: 2010-02-06 Impact factor: 12.479