title: Is anti-h-caldesmon useful for distinguishing smooth muscle and myofibroblastic tumors? An immunohistochemical study.
abstract: Misinterpretation of positive staining of antibodies to desmin, smooth muscle actin, and muscle actin as representing smooth muscle differentiation in the context of a spindle cell tumor is not uncommon. Anti-h-caldesmon is a promising novel immunohistochemical reagent for more specific smooth muscle differentiation. We studied 72 tumors (11 leiomyosarcomas, 26 malignant fibrous histiocytomas [MFHs], 11 fibromatoses, 11 cellular cutaneous fibrous histiocytomas [CCFHs], 5 malignant peripheral nerve sheath tumors, 4 synovial sarcomas, and 4 cases of nodular fasciitis), the reactive myofibroblastic response in 5 cases of acute cholecystitis, and the desmoplastic response surrounding 5 invasive breast carcinomas. Tissues were examined for expression of h-caldesmon, desmin, smooth muscle actin, and muscle actin. Diffuse staining for h-caldesmon was present only within the leiomyosarcomas. Focal staining for h-caldesmon involving less than 1% of lesional cells was present in 3 of 26 MFHs and 1 of 11 CCFHs. There was overlap in staining for the other "myoid" markers in all of the lesions that contained myofibroblasts. Anti-h-caldesmon seems to be a reliable marker of smooth muscle differentiation, and its inclusion in a panel of myoid immunohistochemical reagents should allow distinction of smooth muscle and myofibroblastic tumors.
authors.affiliation: Dept of Pathology, Vancouver General Hospital, BC, Canada.
authors.forename: K M
authors.initials: KM
authors.lastname: Ceballos
authors.forename: G P
authors.initials: GP
authors.lastname: Nielsen
authors.forename: M K
authors.initials: MK
authors.lastname: Selig
authors.forename: J X
authors.initials: JX
authors.lastname: O'Connell
mesh_terms: D000199:Actins / Q000032:analysis; D002148:Calmodulin-Binding Proteins / Q000032:analysis*; D002454:Cell Differentiation; D003893:Desmin / Q000032:analysis; D005208:Fasciitis / Q000378:metabolism; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D007890:Leiomyosarcoma / Q000737:chemistry; D009130:Muscle, Smooth / Q000737:chemistry*; D009132:Muscles / Q000737:chemistry; D009379:Neoplasms, Muscle Tissue / Q000737:chemistry / Q000175:diagnosis*; D018317:Nerve Sheath Neoplasms / Q000737:chemistry; D013584:Sarcoma, Synovial / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D000199:Actins; D002148:Calmodulin-Binding Proteins; D003893:Desmin