Calponin and h-caldesmon expression in atypical fibroxanthoma and superficial leiomyosarcoma

Abstract

To evaluate smooth muscle differentiation, myogenic markers [desmin, alpha-smooth muscle actin (SMA), and muscle-specific actin (HHF35)] have been widely used. Calponin and h-caldesmon, which are cytoskeleton-associated actin-binding proteins, have been reported to be more specific myogenic markers, especially since myofibroblasts express a small amount of h-caldesmon. Atypical fibroxanthoma (AFX) occurs in the sun-exposed skin of the elderly and follows a benign clinical course. Histologically, AFX, which is a pleomorphic spindle cell tumor and considered to be a superficial variant of malignant fibrous histiocytoma, also mimics leiomyosarcoma. AFX has been thought to differentiate along pathways with fibrohistiocytic and myofibroblastic phenotypes. AFX ( n=10), superficial leiomyosarcoma (S-LMS) ( n=17) and benign fibrous histiocytoma (BFH) ( n=17) were analyzed for myofibroblastic and smooth muscle differentiation immunohistochemically from the viewpoint of comparison. AFX and BFH showed immunoreactivities respectively for calponin (3/10, 11/17), desmin (3/10, 1/17), SMA (3/10, 13/17), and HHF35 (1/10, 5/17), but failed to express h-caldesmon (0/10, 0/17). S-LMS had a high immunoreactive rate of calponin (17/17), desmin (13/17), SMA (16/17), and HHF35 (16/17), while also expressing caldesmon (11/17). The results reveal that AFX and BFH have immunoreactivities for several myogenic markers, with myofibroblastic differentiation (calponin: +/-, h-caldesmon: -), but without the smooth muscle differentiation seen in S-LMS (calponin:+, h-caldesmon: +/-). In addition, calponin and h-caldesmon are considered to be useful markers for distinguishing AFX from S-LMS.

Molecular Regulation of Vascular Smooth Muscle Cell Differentiation in Development and Disease

“…It is expressed in skeletal and cardiac muscle during development (Table 1), and within activated fibroblasts under a variety of conditions (55,126,144,217). H 1 calponin, a calcium regulatory protein, is expressed in cardiac myocytes, myofibroblasts, and a variety of tumor cells (179,214,215,271). Metavinculin is an intracellular protein localized at sites of insertion of microfilament bundles into cell membranes and is expressed in cardiac muscle and myofibroblasts in addition to SMC (14,57,73).…”

Urokinase Plasminogen Activator in Injured Adventitia Increases the Number of Myofibroblasts and Augments Early Proliferation

“…Myofibroblasts can also express SM myosin, but it was not always observed in microfilament bundles of myofibroblasts during wound healing nor after balloon catheter injury of the artery [5, 9]. h-Caldesmon, which is a cytoskeleton-associated actin-binding protein, has been reported to be one of the most specific myogenic markers, since myofibroblasts express a negligible amount of h-caldesmon [26]. Smoothelin is a well-accepted highly selective late differentiation marker of SMC [27].…”

Immunohistochemistry in Dermatopathology

“…68,69,[76][77][78][79] Focal expression of myogenic markers (calponin, SMA, HHF35), indicative of myofibroblastic differentiation, can be seen in up to one-third of AFXs. 62,80 Therefore, use of SMA or calponin alone may be insufficient to diagnosis leiomyosarcoma, and a panel should include another muscle marker, such as desmin or h-caldesmon.…”