Computed tomographic features of inflammatory myofibroblastic tumour of the stomach in adult patients: An analysis of five multicentre cases with literature review

A Huge Abdominal Wall Inflammatory Myofibroblastic Tumor: A Report of a Rare Case and Literature Review

An inflammatory myofibroblastic tumor (IMT), frequently misdiagnosed as a malignant neoplasm, is a rare tumor characterized by the presence of myofibroblastic spindle cells and infiltration of inflammatory cells. In the current study, a 49-year-old female patient with a huge abdominal mass in the left abdominal wall was examined. Diagnostic procedures included blood tests, as well as ultrasound, Doppler, and computed tomography (CT) scans, which revealed the presence of a huge complex multiloculated cystic lesion measuring 30 x 37 x 20 cm. The patient underwent complete excision of the mass. Histopathological examination confirmed the benign nature of the tumor and revealed no evidence of malignancy. A comprehensive review of the available literature shows that the current case is one of the few documented cases. The report concluded by emphasizing the importance of surgical intervention as the primary therapeutic strategy and the crucial role of histopathology in the diagnostic process.

A rare case of inflammatory myofibroblast tumor of the stomach successfully treated by inverted laparoscopic and endoscopic cooperative surgery

BACKGROUND

An Inflammatory myofibroblastic tumor (IMT) is a rare intermediate malignancy characterized by myofibroblast proliferation and inflammatory cell infiltration. Various organs are the primary sites of origin. However, primary tumors originating in the stomach tend to be extremely rare, making the diagnosis difficult. Herein, we present a case of IMT originating in the stomach that was effectively managed using inverted laparoscopic endoscopic cooperative surgery (LECS).

CASE PRESENTATION

A 47-year-old male who was admitted to the hospital because of a submucosal tumor that was discovered during upper gastrointestinal endoscopy. The diameter of the tumor was approximately 20 mm. A KIT-negative gastrointestinal stromal tumor was suspected based on the biopsy findings. Therefore, partial resection of the stomach was performed using inverted laparoscopic and endoscopic cooperative surgery. Histopathological examination revealed collagen fiber proliferation from the submucosal layer to the muscular layer, accompanied by infiltration of spindle-shaped cells, lymphocytes, and numerous inflammatory cells. Immunohistochemistry results were positive for SMA and negative for CD34, desmin, and c-kit. IgG4-positive cells were observed with an IgG4/IgG ratio > 50%, and specific nuclei were positive for ALK. Therefore, IMT was diagnosed. This condition may be difficult to diagnose both before and after surgery because of its rarity and submucosal tumor-like morphology.

CONCLUSION

When a submucosal tumor originating in the stomach is observed, IMT should be considered. Partial resection of the stomach with LECS and immunohistochemical diagnosis may be useful.

Mesenchymal tumors of the stomach: radiologic and pathologic correlation

Mesenchymal tumors of the stomach are uncommon, with gastrointestinal stromal tumor (GIST) being the most common among them. Majority of the tumors may arise from cells of Cajal, smooth muscle cells, neural cells, totipotent stem cells, adipocytes or fibroblasts. Imaging plays an important role not only in staging but also in characterizing these tumors. Many of these tumors have characteristic imaging features. GISTs usually present as large cavitating and necrotic tumors with exophytic component. Presence of fat tissue within the tumor suggests a lipoma or a teratoma, early phase hyperenhancement indicates glomus tumor and hemangioma, and delayed contrast enhancement is seen in schwannoma. Their differentiation from epithelial tumors like carcinoma and neuroendocrine tumors is often possible based on the location (mesenchymal tumors are intramural), spread, morphological appearance and enhancement patterns. However, overlapping features exist between these tumors with imaging often being only suggestive. A biopsy is necessary for a definitive diagnosis in many cases.

Clinicopathological features of gastric inflammatory myofibroblastic tumor: Report of five cases

The present study reported on the histomorphological observations and immunohistochemical features of five cases of gastric inflammatory myofibroblastic tumor (IMT). Loosely arranged fat fusiform myofibroblast-fibroblasts and diffusely or patchily distributed inflammatory cells, which formed a diverse morphological structure, were observed. In the mucous vascular structure, mucoid or collagenous areas, fibromatosis- or scar-like lesions were generally <10 mm in size and both had diffuse or patchy plasma cells, lymphocytes and other inflammatory-cell infiltration backgrounds. The immunophenotype was vimentin- and smooth muscle actin-positive with pan-cytokeratin, desmin and calponin expression and CD34-positive foci; furthermore, three cases were positive for anaplastic lymphoma kinase expression. Gastric IMT is rare, with unique histopathological changes and corrosion-like invasion of the smooth muscle of the stomach wall, blood vessels, nerves and adipose tissue. It should be differentiated from a variety of spindle cell tumor types and tumor-like lesions.