Mucoepidermoid Carcinoma of the Palatine Tonsil

Hindawi Publishing Corporation Case Reports in Oncological Medicine Volume 2015, Article ID 827560, 6 pages http://dx.doi.org/10.1155/2015/827560 Case Report Mucoepidermoid Carcinoma of the Palatine Tonsil Lucas Novaes Teixeira, Victor Angelo Martins Montalli, Luiz Carlos Santana Teixeira, Fabrício Passador-Santos, Andresa Borges Soares, and Vera Cavalcanti de Araújo Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755 Campinas, SP, Brazil Correspondence should be addressed to Lucas Novaes Teixeira; Received 4 May 2015; Accepted 30 September 2015 Academic Editor: Ossama W. Tawfik Copyright © 2015 Lucas Novaes Teixeira et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy in both adults and children. It has a slight female predilection and usually presents as a painless, rubber-like or soft mass, which may be fixed or mobile. Histologically, MEC is comprised of a mixture of cell types including mucous, epidermoid, and intermediate cells that can be arranged in solid nests or cystic structures. In the oral cavity, it most frequently occurs at the palate or buccal mucosa. The present paper aimed to describe an unusual case of MEC arising in the palatine tonsil. 1. Introduction 2. Case History Many different malignant neoplasms may arise from the palatine tonsils, with the most common histological type being the squamous cell carcinoma (SCC), which accounts for up to 85% of all cases [1–3]. Malignant lymphoproliferative diseases are the second most frequent malignancy of the palatine tonsil, with the diffuse large B-cell lymphoma (DLBCL) comprising approximately 30% of all lymphomas [4]. Metastatic deposits of lung [5] and gastric carcinomas [6], as well as melanoma [7], renal carcinoma [8], and adenocarcinoma of the colon [9], have also been described in the palatine tonsils. Minor salivary gland tumors exhibit diverse histopathological features as well as a varied clinical behavior [10]. They may be derived from any of the minor salivary glands distributed throughout the oral cavity [11]. Interestingly, despite the presence of minor salivary glands in the palatine tonsils, the development of malignant salivary tumors here is unusual. Indeed, a scarce number of case reports have been documented in the scientific literature [12–14]. The present paper, therefore, aimed to report a case of MEC arising in the palatine tonsil. A 47-year-old man reported experiencing dysphagia and a sore throat for 4 months. The patient was both a heavy smoker (40 cigarettes daily) and an alcoholic. His medical history was significant for Type 2 Diabetes Mellitus. The patient presented with a swelling on the right side of the neck (Figure 1(a)). Intraoral examination revealed an ulcerated mass on the right palatine tonsil (Figure 1(b)). Axial computed tomography (CT) revealed a solid lesion with lobulated and ill-defined margins (Figure 1(c)). An incisional biopsy was performed and the specimen was fixed in 10% buffered formalin. Paraffin sections were prepared for light microscopy using routine procedures. The sections were stained with hematoxylin and eosin (H&E). Microscopic examination revealed a fragment of oral mucosa covered with a nonkeratinized stratified squamous epithelium. A neoplasm of glandular epithelial origin was identified in the lamina propria (Figure 2(a)). The tumor cells were arranged in sheets, exhibiting a uniform morphology with few cells showing atypia and mitotic figures (Figure 2(b)). Clear cells were observed in some areas of the tumor (Figure 2(c)). 2 Case Reports in Oncological Medicine Table 1: Specifications of the primary antibodies. Primary antibody CK-7 CK-13 CK-14 Vimentin Smooth muscle actin Chromogranin p16 Source Dako Dako NeoMarkers Dako Dako Abcam CINtec Histology Dilution 1 : 100 1 : 100 1 : 1200 1 : 300 1 : 100 1 : 500 1 : 250 (a) Retrieval Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min Water bath 95∘ C (citric acid): 30 min (b) Incubation time 60 min 60 min 60 min 60 min 60 min 60 min 60 min (c) Figure 1: (a) The swelling on the right side of the neck, (b) ulcerated mass on the right palatine tonsil, and (c) CT image exhibiting a lobulated and ill-defined lesion (red circle). Table 2: Immunohistochemistry results. Primary antibody CK-7 CK-13 CK-14 Vimentin Smooth muscle actin Chromogranin p16 Result + + + − − − − The samples were subsequently submitted to immunohistochemistry for a subset of cytokeratins (CK), vimentin, smooth muscle actin, chromogranin, and p16, the latter indicating the presence of HPV. The source, clone, concentration, and incubation time of the primary antibodies are described in Table 1. PAS with diastase digestion (PAS + DD) and mucicarmine staining were also performed. CK7 was positive in the neoplastic cells, while the superficial oral epithelium was negative (Figure 2(d)). CK-13 and CK14 positivity was also observed in the neoplastic cells (Figures 2(e) and 2(f)), while vimentin, smooth muscle actin, and p16 were negative (Figure 2(g)). Some areas containing mucous were identified within the tumor, as demonstrated by positivity to PAS + DD and mucicarmine (Figures 2(h) and 2(i)). These results in combination support the diagnosis of MEC (Table 2). The patient was referred to the Hospital of the State University of Campinas (UNICAMP), where the tumor was considered inoperable. The patient underwent chemotherapy and radiotherapy but unfortunately died 6 months after diagnosis. 3. Discussion MEC is one of the most common malignancies of the minor salivary glands [15–17] and is currently described as “a malignant glandular epithelial neoplasm characterized by mucous, intermediate, and epidermoid cells, with columnar, clear cell and oncocytoid features” [18]. According to histopathologic features and the relationship among its cellular components, MEC is classified as low-grade, intermediate-grade, or highgrade [19]. MEC of the minor salivary glands most frequently occurs at the palate and buccal mucosa followed by tongue, gingiva, floor of the mouth, and nasal cavity [20]. This case report describes a case of MEC affecting the right palatine tonsil. The palatine tonsils are considered part of Waldeyer’s ring, whose main role is antibody synthesis [21]. Due to its position at the entrance of the oropharynx, the tonsils are the first soft tissue to encounter inhaled and ingested microorganisms. Thus, they are considered the first line of defense against exogenous aggressors [22]. A large number o (...truncated)