Rom J Morphol Embryol 2016, 57(3):1107–1116 ISSN (print) 1220–0522 ISSN (online) 2066–8279 CASE REPORT Parotid sclerosing mucoepidermoid carcinoma: a case report and immunohistochemical study FLORIN-LIVIU GHERGHINA 1) , ADRIAN CAMEN 2) , MARIA CRISTINA MUNTEANU 2) , CLAUDIU MĂRGĂRITESCU 3) , CĂLIN-GABRIEL ŞARLĂ 4) 1) Department of Physical Medicine and Rehabilitation, University of Medicine and Pharmacy of Craiova, Romania 2) Department of Oral and Maxillofacial Surgery, University of Medicine and Pharmacy of Craiova, Romania 3) Department of Pathology, Faculty of Dentistry, University of Medicine and Pharmacy of Craiova, Romania 4) Department of Physical Education and Sports, “Vasile Goldiş” Western University, Arad, Romania Abstract Here we report the case of a 63-year-old female with a parotid sclerosing mucoepidermoid carcinoma diagnosed and treated at the Department of Oral and Maxillofacial Surgery, Emergency County Hospital of Craiova, Romania. The clinical and imaging investigation revealed a parotid malignant tumor with central fluid-filled cystic formation. Histopathology found an intermediate grade sclerosing mucoepidermoid carcinoma that invaded the adjacent adipose and striated muscle tissues, but without perineural and lymphovascular invasion. The immunohistochemistry investigated mainly biomarkers involved in the induction of a local aggressive behavior. This case report describes a rare parotid sclerosing mucoepidermoid carcinoma with peculiar clinical and morphological characteristic features. The immunohistochemical study sustained its intermediate grade malignancy highlighting the prognostic value of some of the used biomarkers. Keywords: sclerosing mucoepidermoid carcinoma, immunohistochemistry, parotid gland, tumor grade malignancy.  Introduction Mucoepidermoid carcinoma (MEC) is the most common malignant primary salivary gland tumor composed of varying proportions of mucous, intermediate and epi- dermoid cells, with columnar, clear cell and oncocytoid features [1]. Salivary MEC as a malignant glandular epithelial neoplasia is believed to arise from pluripotent reserve cells of the excretory ducts that are capable of differentiating into such variety of cell types [2]. Exposure to ionizing radiation [3–4] and MECT1-MAML2 trans- location and somatic TP53 and POU6F2 mutations [5] seems to be the most important factors involved in the pathogenesis of such salivary gland tumor. Another important feature of salivary MEC is its variety of biological behaviors that generally is correlated with the histological grade of the tumor. However, there are still many controversies in defining the high-grade MEC variant, none of the proposed MEC grading systems being widely accepted [6–8]. Most studies indicate for patients with salivary MEC a favorable outcome, death being reported in cases with high-grade tumors because of distant metastasis [8, 9]. We report here a case of right parotid MEC developed in a 63-year-old female. A comprehensive immunohisto- chemical study was performed concerning the local aggressive behavior of this tumor. Written informed consents were obtained from the patient for publication and images usages.  Case presentation A 63-year-old female presented to our institution with painless swelling in right parotid region for one year, which was slowly grown to the present size. Extraoral examination revealed a mild, firm, oval swelling of about 3 cm in size at the right preauricular area. Patient did not present lymphadenopathy and neither facial nerve involvement. Also, its personal or family records were not significant. Ultrasound examination revealed a solitary mass in the superficial lobe of the right parotid gland with dimensions of 27×20 mm, with heterogeneous echo- texture, with peripheral intense vascularization, irregular shape, and with distal acoustic enhancement divided by a vascularized septum (Figure 1, A and B). A provisional diagnosis of a salivary gland tumor with a potential malignant behavior was considered. Under general anesthesia, following a modified Blair incision a superficial parotidectomy with facial nerve preservation was performed. The tumor was completely excised with negative margins. On gross examination, a whitish gray, firm mass of 4×2.5×2 cm was identified. On cut section, it appeared as solid mass with poorly defined edges that in the central part had a mucin-filled cyst of 0.7 cm diameter surrounded by other smaller cystic structures. Histopathological examination Microscopic examination of the tumor revealed a mixture of malignant epithelial cells with different morphology, respective neoplastic cells with squamoid differentiation, mucous cells (most of goblet-like type), “intermediate” cells, clear cells, columnar apocrine-like cells and sebaceous-like cells (Figure 2, A–F). The neoplastic cells had moderate cellular pleomorphism and rare mitotic figures. R J M E Romanian Journal of Morphology & Embryology http://www.rjme.ro/