Comprehensive Diagnosis of Recurrent Inflammatory Myofibroblastic Tumor in a Young Male Using Immunohistochemistry

Abstract

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm composed of myofibroblastic spindle cells mixed with inflammatory cells. This case report describes an unusual presentation of an IMT in the thigh of a young adult male who presented with painful swelling and multiple ulcerations. The patient had a history of recurrent swellings in the same region, with a previous biopsy suggesting liposarcoma. On examination, the lesion was associated with maggot-infested ulcers and regional lymphadenopathy. Surgical excision and histopathological evaluation revealed spindle-shaped myofibroblasts in a myxoid stroma with mixed inflammatory infiltrate and foreign body-type granulomatous reaction. Periodic acid-Schiff (PAS) stain for fungal elements and Ziehl Neelsen (ZN) stain for acid-fast bacilli (AFB) were negative. Immunohistochemistry demonstrated positivity for smooth muscle actin (SMA) and negativity for anaplastic lymphoma kinase (ALK), Desmin, CD34, S100, STAT6, and Pancytokeratin, confirming the diagnosis of ALK-negative IMT. This case underscores the diagnostic challenges posed by IMTs, particularly when they mimic malignant soft tissue tumors. The ALK-negative status further emphasizes the risk of recurrence and the need for long-term follow-up. Accurate diagnosis requires integration of clinical, histological, and immunohistochemical findings. This case contributes to the limited literature on extrapulmonary, ALK-negative IMT involving the lower extremity and highlights the role of immunohistochemistry in differentiating IMT from its histologic mimics.