Hepatocellular carcinoma (HCC) is considered the sixth most common malignant neoplasm in the world, with 748,000 cases per year [1] . Its etiology is associated with hepatitis A, hepatitis B, hepatitis C and alcohol consumption [2] . Extra-hepatic metastases occur in 50% of cases, predominantly affecting the lung, diaphragm, abdominal lymph nodes and bones [1] . In the oral cavity, metastases are extremely rare [2] and are usually found at an advanced stage of cancer [3] . The first report of oral HCC metastasis was described by Dick et al., in 1957 [4] and to date only 20 cases of gingival metastasis have been found in the literature (Table 1) [1] - [21] . This article has reported an additional case report of oral HCC metastasis in gingiva and a literature review.

A 58-year-old male patient reported pain in the gingiva, which impaired chewing. The patient had a history of hepatitis C infection and an advanced Hepatocellular Carcinoma with pulmonary metastasis 4 months ago. In the intraoral physical examination, there was a vegetative nodular lesion of at least 2 cm, pedunculated, in the gingiva between the teeth 37 and 38, which presented severe mobility. One part of the lesion presented an ulcerated surface, covered by necrotic tissue and, another part, was being traumatized during occlusion (Figure 1). Computed tomography, in a soft tissue window, revealed a well-circum- scribed lesion in the premolar and molar region on the left side. It was also possible to see the juxtaposition of the lesion to the teeth and mandible (Figure 2). The patient presented an advanced stage of Hepatocellular Carcinoma and a pet-scan examination showed hypercaptation in the primary lesion of the liver and areas of lung and jaw metastases (Figure 3). In an MRI, it was possible to identify lesions in the liver and, through a bronchoscopy, pulmonary metastases (Figure 4).

Facing the clinical, imaging findings and the systemic conditions of the patient, the diagnostic hypotheses were: Hepatocellular Carcinoma Metastasis or non-neoplastic proliferative lesion. The proper conduct for the oral lesion would be an incisional biopsy, but since the patient had a prognosis of 2 months of life, the medical and dental team chose to completely remove the lesion and extract the involved teeth, so that the patient could have a better quality of life. The microscopic findings were compatible with malignant neoplasm, demonstrating neoplastic hematogenous infiltration, and epithelial tissue with severe epithelial dysplasia (Figure 5(a)). In order to determine the tissue origin of the lesion, an immunohistochemical examination was performed, in which the result was positive for Hepatocellular Carcinoma metastasis (Figure 5(b) and Figure 5(c)).

Hepatocellular carcinoma is the sixth most common malignant neoplasm, being more frequent in men than in women [3] - [22] . Chronic infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection are the main risk factors for the development of this cancer [23] . Extra-hepatic metastasis is a fairly com- mon occurrence, affecting more than 50% of patients frequently in the lungs, abdominal lymph nodes, diaphragm and bone [4] . Metastases in the oral cavity are rare and, when they occur the most common primary site is lung carcinoma, followed by breast carcinoma and renal cell carcinoma. Considering hepatocellular carcinoma, its metastasis to the mouth region is even rarer, accounting for approximately 1% of the cases, the most affected mandibular and gingival tissues [2] [3] [4] [5] .

The clinical presentation of soft tissue metastases is generally similar to the characteristics of benign or reactive proliferative lesions, such as pyogenic granuloma, and peripheral giant cell lesion [3] . However, the microscopic examination is fundamental to define the final diagnosis. In the present case, although the history of cancer was known and the main suspicion was of an oral metastasis, the microscopic examination was fundamental to confirm the diagnosis. In addition, even the microscopic appearance of a malignant neoplasm, the immunohistochemical examination was performed to confirm the origin of the lesion.

Due to the presence of multiple metastases in vital organs, such as the lungs, the conduct of an excisional biopsy, even if the main diagnosis was a malignant lesion, was taken to offer better quality of life of the patient. We consider maintenance of oral functions fundamental in the palliative phase.

As conclusion, it is worth emphasizing in this work that although the present case already presented the recognized primary disease, some cases of metastatic oral lesions may manifest firstly than the primary site of the neoplasia, and it is important never to neglect any lesion removed. During the clinical examination process, anamnesis is fundamental in the differential diagnosis and the conduct of each case.

Curi, M.M., Curra, C., Condezo, A.F.B., Rodrigues, M.F.M., Pexe, M., Moraes, B., DeAntoni, C.C., Moreira, R. and Cardoso, C.L. (2017) Rare Me- tastatic Lesion Affecting the Mouth: Case Re- port and Review. Journal of Cancer Therapy, 8, 399-404. https://doi.org/10.4236/jct.2017.84034