Mucosa-Associated Lymphoid Tissue Lymphoma of the Sublingual Salivary Gland: A Case Report

Abstract

Background: Mucosa-associated lymphoid tissue (MALT) lymphoma is now established as a distinct type of non-Hodgkin lymphoma. This tumor is a low-grade B-cell lymphoma that may involve a variety of extranodal sites. The stomach is the most common site of involvement, followed by other gastrointestinal organs, respiratory tract, and skin. The salivary gland is also typically presenting site. However, MALT lymphomas of salivary glands are usually involved the parotid gland and the sublingual gland involvement is quite rare. We report a case of a male patient with sublingual gland enlargement, who was diagnosed with MALT lymphoma. Case Presentation: An 81-year-old male presented to our outpatient clinic with a chief complaint of swelling of the floor of the mouth. No medical history and no medication were identified. On intraoral examination, a fibrous and painless enlargement of the right sublingual gland was noted. No enlargement of the submandibular glands and no cervical lymphadenopathywere noted on extraoral examination. A CT scan showed a tumor-like image in the right side of the floor of the mouth. An MRI also revealed a mass in the right sublingual gland with the size of 25 mm x 15 mm x 18 mm. A tentative diagnosis of malignant tumor of the sublingual gland was made and the biopsy specimen revealed suspicion of malignant lymphoma. Subsequently, surgical removal of the right sublingual gland with surrounding tissue was performed as an initial treatment, as well as for confirming a definitive diagnosis. The surgical specimen was compatible with lowgrade B-cell lymphoma of MALT type on histological evaluation. The patient was referred to the hematology department for further workup and treatment. According to the Ann Arbor staging system, this case was considered a stage IE MALT type lymphoma. The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology indicates that if the non-gastric MALT lymphoma is stage I-II, then radiation therapy is preferred. However surgery may be considered for certain sites. This guideline also states that surgical excision for adequate diagnosismay be appropriate treatment for disease. Accordingly, no additional treatment was employed following surgery and the patient has been observed. After the surgical treatment, the patient continues to be free of any evidence of lymphoma. MALT lymphoma is commonly associated with preexisting autoimmune disease such as Sjógren's syndrome or with chronic immune stimulation such as Helicobacter pylori infection. However, this case was not associated with these diseases and the patient had no considerable medical history. Conclusion: In the present study,we report the case of a patient diagnosed with MALT lymphoma of the sublingual gland. Because MALT lymphoma has a slow progression of spread from the primary site, local treatment approaches are important. We performed surgical treatment as an initial treatment.