Inflammatory Myofibroblastic Tumor of the Parotid Gland:

Inflammatory myofibroblastic tumor of the submandibular gland Harboring MSN-ALK gene fusion: A case report and literature review

Inflammatory myofibroblastic tumors (IMTs) are rare lesions with distinct clinical, pathological, and molecular characteristics. IMTs typically arise in the abdominal soft tissues, including the mesentery, omentum, and retroperitoneum, followed by the lungs and mediastinum, and usually affect both children and young adults. Herein, we present a rare case of an IMT in the submandibular gland of a 47-year-old male patient. Microscopically, the tumor displayed an infiltrative growth pattern with diffuse glandular tissue destruction. Their backgrounds revealed characteristic spindles and inflammatory cells. Immunohistochemistry revealed positivity for anaplastic lymphoma kinase (ALK), smooth muscle actin, and calponin in neoplastic cells. The inflammatory cells and some neoplastic cells were positive for CD68. In contrast, negative staining for cytokeratin, desmin, and CD30 was observed. Furthermore, fluorescence in situ hybridization revealed ALK gene rearrangements, and next-generation sequencing detected a moesin (MSN)-ALK gene fusion. This case highlights a rare and unique occurrence of IMT originating from the submandibular gland, which exhibited an MSN-ALK gene fusion.

Inflammatory Pseudotumor (IPT) and Inflammatory Myofibroblastic Tumor (IMT): A Representative Literature Review Occasioned by a Rare IMT of the Transverse Colon in a 9-year-old Child

Aims and Background

Inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT) represent different entities. However, it is only in recent years that this has been taken into increasing consideration. Some authors still use both terms synonymously or interchangeably. Inflammatory myofibroblastic tumor is a real neoplasm because of the proliferation of myofibroblastic cells. Inflammatory pseudotumor is a more inflammatory reactive or regenerative entity and shows an overlapping with immunoglobulin G4-related disease.

Methods and Study Design

To analyze the current situation, 443 publications from the last 5 years (2009 to February 2014) were included. Reports involved 938 patients and 956 organ sites. The age distribution is twin peaked with one maximum in childhood and the other between 50 and 60 years of age. This distribution is questionable due to the more frequent occurrence of IPT in the liver and of IMT in the lung. Inflammatory pseudotumors mainly occur in older patients; IMTs in children and young adults.

Results and Conclusions

The liver and biliary tract were the most commonly affected of all body regions, at 32%. This was followed by the lung, including the respiratory tract, at 27%, and by the gastrointestinal tract, at 10%. Lesions of the large bowel, as in the present case of a 9-year-old boy, are very rare. There were organ-related as well as nonspecific clinical symptoms, such as fever, weight loss, and fatigue. Laboratory test results revealed anemia and elevated inflammation-dependent parameters. The patterns in medical imaging are variable and nonspecific. Morphology often suggests a malignant process. For this reason, therapy in most cases is surgical, but this is required more often in IMTs. Many IPTs could be treated conservatively.

[Patterns of xanthogranulomatous reaction in salivary glands. Histomorphological spectrum and differential diagnosis]

Xanthogranulomatous inflammation is an uncommon subtype of chronic inflammatory processes that has been mainly reported in the kidneys, gallbladder and other less common sites. Due to the presence of tumefactive mixed inflammatory infiltrates with variable involvement of surrounding soft tissues, this benign condition is often mistaken for a malignancy on clinical examination. In the salivary glands xanthogranulomatous inflammation is rare and mainly represents reactive changes secondary to a preexisting lesion, in particular infarcted Warthin tumors as well as ruptured ductal cysts and other sialectatic ductal changes. A special type of xanthogranulomatous salivary gland disease is represented by the rare primary (idiopathic) xanthogranulomatous sialadenitis without identifiable predisposing parenchymal or ductal lesions. The histological differential diagnosis is mainly based on the dominant histological pattern and encompasses among others inflammatory pseudotumors of various etiologies (e.g. inflammatory myofibroblastic tumor, IgG4-related disease and sarcoidosis), neoplastic and paraneoplastic xanthogranulomatosis, malignant lymphoma and carcinoma with secondary xanthogranulomatous reactions. Thus, identification of the underlying lesion is necessary for correct classification and to avoid overlooking more serious neoplastic or autoimmune diseases.