Except for 1 case with a positive EMA staining result and 1 case with focally positive cytokeratin AE1/AE3 staining result, negative outcomes were reported for EMA, neurofilament, cytokeratin, β-catenin, ALK, cytokeratin AE1/AE3, and synaptophysin, thereby excluding epithelial, perineural, neuronal, and neuroendocrine cell lineage and ruling out some of the important differential diagnoses, such as fibromatosis and inflammatory myofibroblastic tumor. The gene discussed is ALK; the disease is fibromatosis.