Rare presentation of inflammatory myofibroblastic tumor on a digit

Abstract

Inflammatory myofibroblastic tumors (IMTs) are rare soft tissue neoplasms consisting of a mixture of spindle‐shaped myofibroblasts or fibroblasts and a variable inflammatory infiltrate composed of eosinophils, plasma cells, and lymphocytes. Associations with trauma and infectious agents have been proposed, but the etiology is unknown. While IMT predominantly develops in the lungs of pediatric patients or young adults, extrapulmonary IMT is well documented and may occur anywhere. Cutaneous IMT is rare and few have been reported on the hand in the English language. The mean age of onset is 10 years, with a slight female predilection. IMT demonstrates intermediate malignant potential, with a tendency to recur locally. Metastases are rare. According to a recent review, anaplastic lymphoma kinase (ALK) positivity on immunohistochemistry is related to local recurrence, but not distant metastases. We report an unusual case of a 36‐year‐old male, with a lesion on the right second digit, displaying classic histopathologic and immunohistochemical features of IMT, including ALK staining, and confirmatory fluorescence in situ hybridization‐proven ALK gene rearrangement.