抄録
A 62-year-old female visited our hospital complaining of a swelling in her right cheek. Computed tomography (CT) revealed a well-demarcated solid tumor, 2 × 2 cm in size, on the outer side of the right masseter muscle, located apart from the parotid gland. We suspected malignant lymphoma using fine-needle aspiration cytology, and an open biopsy was performed. Histologically, proliferation of atypical small cleaved lymphocytes was seen around the enlarged lymph follicles. Residual salivary duct epithelium was detected within the lesion. In immunohistochemical staining, these tumor cells were positive for CD20, CD79a and bcl-2, but not positive for CD10, CD3, and CD45RO. We diagnosed the tumor as mucosa-associated lymphoid tissue (MALT) lymphoma arising in an accessory parotid gland. According to the histological diagnosis, radiotherapy was done and the patient had complete remission. However, forty-three months after treatment, she had a recurrent tumor in the inguinal lymph node.
