Is anti-h-caldesmon useful for distinguishing smooth muscle and myofibroblastic tumors? An immunohistochemical study

• Published in: American journal of clinical pathology 2000-11, Vol.114 (5), p.746-753
• Main Authors: CEBALLOS, Katherine M, NIELSEN, Gunnlaugur P, SELIG, Martin K, O'CONNELL, John X
• Format: Article
• Language: English
• Subjects: Actins - analysis; Biological and medical sciences; Calmodulin-Binding Proteins - analysis; Cell Differentiation; Desmin - analysis; Fasciitis - metabolism; Histiocytoma, Benign Fibrous - chemistry; Humans; Immunoenzyme Techniques; Investigative techniques, diagnostic techniques (general aspects); Leiomyosarcoma - chemistry; Medical sciences; Miscellaneous. Technology; Muscle, Smooth - chemistry; Muscles - chemistry; Neoplasms, Muscle Tissue - chemistry; Neoplasms, Muscle Tissue - diagnosis; Nerve Sheath Neoplasms - chemistry; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Sarcoma, Synovial - chemistry; Sensitivity and Specificity
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1309/k5jp-a9en-uwn7-b5gg

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.