Inflammatory myofibroblastic tumour

A rare type of tumor composed of myofibroblastic spindle cells and inflammatory cells

Inflammatory myofibroblastic tumour (IMT) is a rare neoplasm characterized by the proliferation of myofibroblastic spindle cells accompanied by a prominent inflammatory infiltrate. These tumors can occur in various parts of the body and are most commonly found in the lungs, abdomen, and pelvis.

Pathophysiology

IMTs are composed of myofibroblasts, which are cells that have features of both fibroblasts and smooth muscle cells. The inflammatory component typically includes lymphocytes, plasma cells, and eosinophils. The exact cause of IMT is not well understood, but it is thought to be related to an abnormal immune response or infection. Some cases have been associated with genetic alterations, such as rearrangements of the ALK gene.

Clinical Presentation

The symptoms of IMT vary depending on the location of the tumor. In the lungs, patients may experience cough, chest pain, or shortness of breath. Abdominal IMTs can cause pain, swelling, or gastrointestinal symptoms. Systemic symptoms such as fever, weight loss, and malaise may also be present.

Diagnosis

High magnification image of an inflammatory myofibroblastic tumour

Diagnosis of IMT is based on a combination of imaging studies, histopathological examination, and immunohistochemical staining. Imaging techniques such as CT scan or MRI can help determine the size and location of the tumor. A biopsy is necessary to confirm the diagnosis, revealing the characteristic spindle cell proliferation and inflammatory infiltrate. Immunohistochemistry may show positivity for markers such as ALK, SMA, and desmin.

Treatment

The primary treatment for IMT is surgical resection, which is often curative. In cases where the tumor is not resectable, or if there is recurrence, additional treatments such as corticosteroids, nonsteroidal anti-inflammatory drugs, or targeted therapies like ALK inhibitors may be used. Radiation therapy and chemotherapy are generally less effective.

Prognosis

The prognosis for patients with IMT is generally favorable, especially if the tumor can be completely resected. However, there is a risk of recurrence, and in rare cases, the tumor can behave aggressively or metastasize.

Related pages

• Myofibroblast
• Neoplasm
• ALK gene