Specific but variable expression of h-caldesmon in leiomyosarcomas: An immunohistochemical reassessment of a novel myogenic marker

Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry (Impact Factor: 2.01). 01/2002; 9(4):302-8. DOI: 10.1097/00129039-200112000-00003
Source: PubMed


h-Caldesmon is considered a novel specific marker for tumors with smooth muscle differentiation. To reassess its diagnostic use, the authors evaluated the immunohistochemical expression of h-caldesmon and other myogenic markers (calponin, alpha-smooth muscle actin, HHF35, and desmin) in 30 leiomyosarcomas (external soft tissues [15], retroperitoneum [8], uterus [5], other sites [2]), 26 myofibroblastic lesions, and 26 fibrohistiocytic tumors of varying biologic potential and histology. In contrast with previous data, h-caldesmon was expressed only in 11 (36%) of the 30 leiomyosarcomas analyzed, whereas they consistently expressed actins and frequently expressed calponin (86%) and desmin (76%). Leiomyosarcomas with the expression of h-caldesmon were well or moderately differentiated and primarily confined to the retroperitoneum or uterus. All but one leiomyosarcomas in the external soft tissues examined were negative for h-caldesmon, and the h-caldesmon-negative tumors showed moderately to poorly differentiated morphology. All myofibroblastic lesions examined were negative for h-caldesmon despite their constant expressions of at least one of the other markers. h-Caldesmon was not expressed in fibrohistiocytic tumors either, although focal positivity for the other markers was seen in subsets of the tumors. Thus, h-caldesmon can be regarded as a specific myogenic marker. However, one should be aware that the expression of h-caldesmon in leiomyosarcomas can be more variable according to their locations and/or extent of smooth muscle differentiation than considered previously.

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