MYOFIBROBLASTIC LESIONS IN THE ORAL CAVITY: IMMUNOHISTOCHEMICAL ANALYSIS

Objective To characterize immunohistochemically a group of oral myofibroblastic lesions (MLs). Study Design MLs incorporated during the period of 1997-2014 were retrieved from the files and records of the Department of Oral Pathology. Cases of myofibroma (MF), nodular fasciitis (NF), desmoplastic fibroma (DF), and 2 myofibroblastic sarcoma (MS) were stained with antibodies against alpha-smooth muscle actin (α-SMA), H-caldesmon, vimentin, desmin, β-catenin, anaplastic lymphoma protein kinase (ALK-1), and Ki-67. Results Nineteen of 22 cases of MF, 2/5 NF, 1/10 DF, and 1/2 MS were positive for α-SMA. All cases of MF, NF, DF, and MS were positive for vimentin. One-half of MS cases were positive for desmin. Six out of 10 cases of DF were positives for β-catenin. Two cases of MF were positive for ALK-1. All cases of MF, NF, DF, and MS were negative for H-caldesmon. The Ki-67 labeling index was 10% and 8/22 cases of MF, 3/5 cases of NF, and 2/2 cases of MS exhibited a rate of ≥ 10% for this marker. Conclusions The application of this panel of markers can help the diagnosis of oral MLs, in particular the distinction between fibroblastic, myofibroblastic, and muscle cells proliferation.