Nevertheless, local excision is an option in selected cases. Most IMTs require surgery to obtain definite diagnosis and treatment. described an IMT of the gastric remnant in woman with a prior gastrectomy. reported a case with peritoneal dissemination and Leon et al. It was described a case that bled spontaneously into the peritoneal cavity and developed a hemoperitoneum. Immunohistochemically, GIST is typically positive for CD117 but negative for ALK, whereas IMT shows an opposite profile.Ĭlinically, IMT presents with an abdominal mass or cystic lesion with related compressive symptoms, such as abdominal pain and vomiting. In addition, some GIST cells have cytoplasmic vacuoles, a feature not seen in the IMT. GIST typically does not have the inflammatory background seen in the IMT. GIST may show cyst formation, hemorrhage, or necrosis, which were only occasionally seen in some IMTs.
They include gastrointestinal stromal tumor (GIST), inflammatory fibroid polyp, smooth muscle neoplasm, peripheral nerve sheath tumor, solitary fibrous tumor, fibromatosis, and, rarely, the follicular dendritic cell sarcoma. In our case, the volume of the tumor, the presence of cellular atypia, and the high Ki-67 labeling index suggest aggressive neoplasm.Īs far as the differential diagnosis is concerned, there are a few tumors or lesions in the stomach that must be distinguished from IMT. The myofibroblastic cells in IMTs are spindled and/or epithelioid. These patterns are often mixed in a single tumor. Three architectural patterns have been described in IMT: myxoid hypocellular pattern, a cellular fascicular or nested pattern with variable amounts of myxoid stroma, and a sclerotic, hyalinized pattern with minimal myxoid stroma. This entity is characterized by a myofibroblastic proliferation, a lymphoplasmacytic infiltrate distributed among the tumor cells and a myxoid background stroma. However, studies on cytogenetic abnormalities, such as rearrangements of the ALK gene on chromosome 2p23, clonal chromosome abnormalities, and DNA aneuploidy, and the role of oncogenic viruses in the pathogenesis of IMT suggest that it is a real neoplasm. It has been debated whether IMT is a tumor or inflammation, and also whether it is benign or malignant. The histological appearance of a gastric IMTs is similar to that of soft tissue IMTs. However, recently the authors verified that the IMT can occur in any organ of the body and in all ages. It was once accepted that IMT is primarily a disease of children and young adults and commonly occurs in the lungs. The primary inflammatory myofibroblastic tumor (IMT) is a very rare neoplasm in adults and the exact nature of the disease is not yet completely understood. We report a case of gastric IMT in an adult woman and a review of the literature. Ĭlinically, the majority of IMTs are benign but they require adequate surgical treatment because it has a tendency for local recurrence. ALK expression distinguishes IMT from other differential diseases diagnostic, such as fibromatosis, nodular fasciitis, leiomyosarcoma, and gastrointestinal stromal tumor, which do not express ALK.
Positive immunohistochemical staining of ALK is approximately in 40–100% of IMTs, depending on the anatomic sites. At the molecular level, approximately half of IMTs contain a clonal cytogenetic aberration that activates the anaplastic lymphoma kinase (ALK-) receptor tyrosine kinase gene at 2p23. Nevertheless, IMT of the stomach is extremely rare. IMT grows as a result of a reactive inflammatory or postsurgery process and commonly occurs in the lung, mesentery, omentum, and retroperitoneum, but it can also be seen in the extremities, head and neck, genitourinary tract, and other organs. This distinctive neoplasm is composed of myofibroblastic cells associated to an inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils that relapse often and rarely metastasizes. Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm that occurs preferentially in children and young adults.
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