A case of mucosa-associated lymphoid tissue (MALT) lymphoma arising in the accessory parotid gland

Abstract

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. [Oral Med Pathol 2007; 12: 19-22]

Accessory parotid gland tumors

“…[16–18] Till date only, four cases of NHL of accessory parotid gland have been reported in English literature. [235]…”

“…Accessory parotid gland tumors are reported to occur in 1–7.7% of all the parotid gland tumors. [5–7] In the literature, four cases of NHL arising from the accessory parotid gland have been reported till date. [235] A high index of suspicion is necessary for making a preoperative diagnosis as this is an uncommon occurrence.…”

“…[5–7] In the literature, four cases of NHL arising from the accessory parotid gland have been reported till date. [235] A high index of suspicion is necessary for making a preoperative diagnosis as this is an uncommon occurrence. For surgical treatment, this tumor can be approached through either of two incisions, i.e., standard modified Blair's incision or mid cheek incision.…”

Mucosa-associated lymphoid tissue lymphoma of the accessory parotid gland presenting as a simple cheek mass

“…Possible causes include Helicobacter pylori -associated chronic gastritis, gastrointestinal bacterial infections, pulmonary bacterial infections, autoimmune diseases (e.g., Sjogren's syndrome and Hashimoto thyroiditis), and hepatitis C viral infection. [2,6] Such conditions of chronic inflammation induce proliferation of lymphoid tissue, leading to the development of MALT lymphoma. [1,3,9] In our case report, the patient had a history of an autoimmune disease (i.e., MG) and thymectomy.…”

“…[1–3] It usually occurs in the gastric mucosa, but may also develop in other sites, such as the gastrointestinal tract, lung, breast, ocular adnexa, and salivary glands. [4] However, it is unusual for MALT lymphoma to develop in the parotid gland, [1,4,5] and cases of MALT lymphoma in the accessory parotid gland are especially rare [6] ; thus, such cases are easily confused with other types of soft tissue masses, such as abscesses, sialoceles, epidermal inclusion cysts, and other benign parotid gland tumors. We report a case of a 56-year-old woman with MALT lymphoma that developed in the accessory parotid gland, which could have easily been mistaken for another type of soft tissue mass.…”