Inflammatory myofibroblastic tumor of the lung: a comprehensive narrative review of clinical and therapeutic insights

Abstract

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm classified by the World Health Organization as an intermediate malignancy with less than a 5% chance of metastasis. IMTs consist of myofibroblastic and spindle fibroblastic cells accompanied by inflammatory infiltration, primarily affecting patients under 16 years old, though they can also occur in adults. The etiology and pathogenesis of IMTs remain unclear, with possible contributing factors including inflammation, trauma, autoimmune diseases, prior surgery, viral infections, and uncontrolled myofibroblast proliferation. The primary treatment is complete surgical resection, which is associated with long-term survival and a significantly reduced recurrence rate of 2%, compared to 60% for incomplete resections. Chemotherapy is generally not recommended but may be necessary for unresectable tumors. Advances in histopathological diagnosis provide deeper insights into IMT biology, aiding in the selection of appropriate treatments. This paper presents a comprehensive review of the literature on this rare clinical entity.

Keywords: inflammatory myofibroblastic tumor; mesenchymal tumor; myofibroblastic proliferation; pulmonary inflammatory myofibroblastic tumor; rare lung tumor.

Figure 1

PRISMA flow diagram of the study selection process

Figure 2

A – Computed tomography (CT) scan of the chest reveals a neoplastic mass in the right lower lobe of the lung. B – Positron emission tomography/computed tomography (PET/CT) scan of the lung neoplasm showing a maximum standardized uptake value (SUVmax) of 8.2, indicative of high metabolic activity

Figure 3

Immunohistochemical analysis. A – Vimentin positive staining at 100× magnification. B – Calponin positive staining at 400× magnification. C – Smooth muscle actin (SMA) positive staining at 400× magnification. D – Ki-67 staining at 400× magnification, demonstrating a proliferation index of 1–5% in neoplastic cells