A case report of spindle cell myoepithelioma with extensive lipomatous metaplasia and thick collagen bundles in the submandibular gland

A case of cutaneous syncytial myoepithelioma with extensive adipocytic metaplasia: Usefulness of EWSR1-PBX3 gene fusion analysis

Cutaneous syncytial myoepithelioma (CSM) is a recently recognized variant of myoepithelial neoplasms. CSM is characterized by an intradermal syncytial proliferation of spindled, ovoid, and histiocytoid cells. Immunohistochemically, tumor cells usually show strong positivity for S-100 and EMA. Here, we report a case of CSM in the thigh of a 51-year-old Japanese woman. Histopathological findings showed a sheet-like growth of ovoid cells and histiocytoid cells with an eosinophilic syncytial cytoplasm, and adipocytic metaplasia was widely observed in the tumor. Immunohistochemical staining revealed a diffuse strong pattern for EMA, smooth muscle actin (SMA), and HHF35 and variable positivity for S-100 protein and p63 in ovoid and histiocytoid cells without significant mitotic figures or pleomorphism. In addition, EWSR1-PBX3 gene fusion, which is characteristic of CSM, was observed in the tumor. Based on these findings, we diagnosed the patient as having CSM. Our case suggests that CSM could show extensive adipocytic metaplasia, which could make its histopathological diagnosis challenging. This article is protected by copyright. All rights reserved.

Parapharyngeal space pleomorphic adenoma with extensive lipometaplasia - A rare unique pathological entity

Pleomorphic adenoma (PA) is the most common neoplasm of the salivary gland. Fat-containing tumors encountered in salivary glands are very rare. We had a case of PA of parapharyngeal space and surprisingly the final histopathology showed an unusual finding of lipometapasia. We believe that this is the first case from parapharyngeal space to be reported in the literature. The aim of this report is to discuss the behavior of lipometaplasia in PA with review of literature. Pathological characterization of this rare tumor might help in proper classification and enhance their recognition.

Myoepithelioma of bone: ultrastructural, immunohistochemical and molecular study of three cases

Primary intraosseous myoepithelial tumors are rare neoplasms with only a handful of cases described in the medical literature. To date, intraosseous variant of benign myoepithelioma, due to its rarity, has not been studied ultrastructurally, and only one case of a malignant intraosseous myoepithelioma has been described. Three cases were retrieved from the files at the Massachusetts General Hospital (MGH). A diagnosis of benign myoepithelioma was made in case 1 and malignant epithelioma in cases 2 and 3. Ultrastructurally, intermediate filaments (without dense bodies) were found in each case with an abundance in case 1 and lesser amounts in cases 2 and 3. Surprisingly, cell junctions were not identified in case 1. However, they were found occasionally as intermediate junctions in case 2 and were easily identified as desmosome like junctions in case 3. The nucleus was irregular in the neoplastic cells of benign myoepithelioma which contrasted with cases 2 and 3 where the nuclei were oval yet had visible nucleoli. Herein, we add three new cases, including two new cases of malignant myoepithelioma. We also provide the first ultrastructural description of benign myoepithelioma of bone.

Differential immunohistochemical expression of type I collagen and matrix metalloproteinase 2 among major salivary glands of young and geriatric mice

Objective

This study aimed to demonstrate the immunohistochemical changes associated with MMP-2 and type 1 collagen separately for the first time in the major salivary glands (the parotid, submaxillary, and sublingual glands) that occur with aging in mice.

Material and Methods

Fourteen Balb/c white mice (50-80 g) were used in this study. The animals were divided into two equal groups. Group I consisted of young animals (2-month-old) (n=7) and Group II consisted of older animals (18-month-old) (n=7). After routine histological follow-ups, Hematoxylin-eosin (H&E), Masson’s Trichrome staining and immunohistochemical staining was performed for type I collagen and MMP-2.

Results

We observed that there were age-related decreases in the number of acinar cells, increase in eosinophilic zymogen granules in cells, collagen accumulation in fibrotic areas and dilatation in interlobular ducts. Also, while type I collagen and MMP-2 immunoreactivity were moderate in the salivary glands of the young mice, they were high in the salivary glands of the old mice (p=0.001). In the H-score assessment, MMP-2 immunoreactivity was lower at a significant level in young mice than in old mice (p=0.001).

Conclusions

This study showed that anatomical, physiological and morphological abnormalities occur in all three major salivary glands as a natural consequence of aging.