A Rare Case of Myoepithelial Carcinoma in a 28-year-old Male with History of Pleomorphic Adenoma

A 29-year-old male presented to SGM Cancer Hospital, Wardha, with hard swelling on the posterolateral aspect of the palate on the left side. The patient was addicted to tobacco and Kharra chewing. The patient had a history of a similar palatal lesion in 2009 which was treated with wide local excision. On histopathological examination, it was diagnosed as pleomorphic adenoma. He recovered completely and was fine for almost 14 years. Then, he presented with a similar lesion over the palate in 2023. The tumor size was 2.5 cm × 2.4 cm × 1.5 cm. Again, wide local excision was done followed by radiotherapy which the patient tolerated well. Haematoxylin and eosin, ×40 section from the tumor showed cells composed of two types, the inner ductal cells with round-to-ovoid nuclei, inconspicuous nucleoli, and eosinophilic-to-amphophilic cytoplasm (red circle). Outer myoepithelial cells with vacuolated cytoplasm (Black arrow). Histopathological features were suggestive of myoepithelial carcinoma (MC). The lesion showed positive perineural invasion. TNM stage was pT2NxMx. Immunohistochemistry reports showed Ki67 (15%), p63, epithelial membrane antigen, and cytokeratin were positive. Figure 1 shows the intraoral view of the lesion at presentation. Figure 2 shows a histopathological picture of the excised tumor.Figure 1: Intra-oral view of lesion at presentationFigure 2: The black arrow points toward a dense proliferation of pleomorphic tumor cells with hyperchromatic nuclei. There is evidence of periductal hyalinization and stromal desmoplasia. The red circle highlights ductal structures with central lumen formation, within a background of malignant myoepithelial cells suggesting tumor differentiationOne of the similar cases of myoepithelial neoplasm arising from pleomorphic adenoma was reported by Yaqoob et al.[1] MC is a relatively rare tumor that remains undiagnosed most of the time because of histopathological heterogeneity. MC is a malignant salivary gland neoplasm characterized by tumor cells that demonstrate cytologic differentiation toward myoepithelial cells and lack acinar differentiation. It constitutes around 0.4%–0.6% of all salivary gland tumors and 1.2%–1.5% of carcinomas.[2] As per the study by Zheng et al., brachytherapy is one of the most feasible and effective modalities for the treatment of MC.[3] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.