Myopericytoma of low grade malignancy in the oral cavity.

Department of Pathology, Shizuoka City Shimizu Hospital, Shizuoka, Japan.
Rare tumors 01/2012; 4(1):e9. DOI: 10.4081/rt.2012.e9
Source: PubMed

ABSTRACT Myopericytoma (MPC) of the oral cavity is extremely rare. Herein reported is a case of MPC of low grade malignancy in the oral cavity. A 61-year-old man noticed a tumor of the cheek mucosa, and admitted to our hospital. Oral examination revealed a reddish elevated tumor of the cheek mucosa. Tumorectomy with wide margins was performed. The clinical diagnosis was pyogenic granuloma. Grossly, the tumor was reddish, and measured 1×1×1 cm. Microscopically, oval to spindle tumor cells with hyperchromatic vesicular nuclei and many vasculatures were seen. The tumor cells were contiguous and mixed with endothelial cells in many blood vessels, thus resembling pericytes. Mitotic figures were scattered. The surgical margins were negative for tumor cells. Immunohistochemically, the tumor cells were positive for vimentin, α-smooth muscle actin and p53. The Ki67 labeling was 40%. The tumor cells were negative for cytokeratins (AE1/3 and CAM5.2), CD31, CD34, S100 protein, HMB45, CD10, vimentin, desmin, and factor VIII-related antigen. The endothelium of the vessels were positive for vimentin, CD31, CD34 and factor VIII-related antigen, but negative for α-smooth muscle actin, p53, cytokeratins (AE1/3 and CAM5.2), S100 protein, HMB45, CD10, vimentin, and desmin. The Ki67 labeling was 5%. Because the pericytoid tumor cells showed α-smooth muscle actin and negative for endothelial markers, MPC was diagnosed. In addition, because there was some atypia and mitotic figures were scatters and also because the tumor cells were positive for p53 and Ki67 labeling was high, a pathological diagnosis of MPC with low grade malignancy was made. No recurrence was observed, and the patient is now free from tumor 6 months after the operation.

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    ABSTRACT: Objective The aim of this study was to analyze the clinical pathological features of the atypical glomus tumor of the stomach, and explore its biological behavior and clinical significance. Methods a 43-year-old female was admitted due to passing black stool for 5 months. The melena of the patient occurred after eating the crabs. The endoscopic ultrasonography (EUS) was performed, showing a hypoecho nodule found at the body of the stomach, suggesting the diagnosis of gastric stromal tumor. After onset of disease, no specific clinical symptoms were observed except for the slight feeling discomfort in upper abdominal region. The gastroscopy was performed under the general anesthesia: there was a spheroidal nodule measuring 2.5 cm × 3.0 cm at the anterior wall of the body of stomach near the side of lesser curvature with the focal erosion of gastric mucosa. The DualknifeTM and the snare were used to excise the tumor in full thickness. Grossly, the tumor nodule measured 2.5 cm in diameter. The cut surface was solid, showing moderate consistency and grey red in colour. Microscopically, this tumor presented a well circumscribed nodule. It composed of the rounded neoplastic cells which were mainly arranged in solid pattern. The tumor cells had well-defined cell membranes, centrally placed, round nuclei and amphophilic cytoplasm. Immunohistochemical staining showed the positive expression of smooth muscle actin (SMA), caldesmon and vimentin; meanwhile detecting the negative expression of desmin, pan-cytokeratin, CD34, CD117 and S-100 in tumor cells. The Ki-67 labelling index of tumor was 8%. Results Combined with the histopathological features, immunophenotype of the tumor, deep location in abdominal cavity and with greater diameter larger than 2 cm, and the diagnosis of atypical glomus tumor of the body of the stomach in this case was established. Conclusion The atypical glomus tumor of the body of the stomach is a rare mesenchymal tumor. The following differential diagnosis should be included as following: gastrointestinal stromal tumor (GIST), paraganglioma, myopericytoma and the angioleiomyoma. The immunohistochemistry exerts an essential role during the diagnosis of this tumor. The deeper location and larger size implicate its undetermined biological behavior.
    The Chinese-German Journal of Clinical Oncology 11(11).


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