Extranodal Marginal Zone Lymphoma of the Parotid Gland

Abstract

Non Hodgkin lymphomas correspond to 25 % of all head and neck cancers. These rare tumors only include less than 5 % of malign tumors in parotid region. Differential diagnosis of these tumors cover many malign and benign tumors of the parotid gland. Definite diagnosis depends on sufficient tissue material of parotidectomy specimen. Treatment modality is surgical removal of the lesion with or without additional radiation and chemotherapy depending on the stage of the tumor. Prognosis is better than other forms of the B-cell lymphoma. We present a 54 year old woman who suffered from progressively and slowly growing mass on parotid region, without any inflammatory disease or chronic infection, diagnosed with mucosa associated lymphoid tissue lymphoma of the parotid gland. Parotid gland was totally excised by superficial parotidectomy and there is no recurrence after 5 years postoperative period.

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

“…[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. [10] This history of chronic inflammation is thought to have induced lymphoid tissue proliferation, leading to the development of lymphoma.…”

“…[11] This gland may be either continuous with or separated from the main parotid gland. [11] Among the tumors that may arise in the parotid gland, NHL only accounts for 1% to 4%, [1,4] with subtypes including follicular lymphoma, diffuse large B-cell lymphoma, and MALT lymphoma. [6] Of these subtypes, development of MALT lymphoma in the parotid gland is rare [1,5] ; further, its development in the accessory parotid gland is especially rare, and such cases have scarcely been reported.…”

“…Adjuvant radiotherapy is also effective. [1,12] Further, PET-CT must be performed to evaluate lymphomatous involvement at other sites.…”

“…Mucosa-associated lymphoid tissue (MALT) lymphoma, a form of extranodal marginal zone B-cell lymphoma, originates from a proliferation of lymphoid tissue caused by chronic inflammation at an extranodal site. [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.…”

Mucosa-associated lymphoid tissue lymphoma of the parotid gland – a case report

“…Lymphomas are generally classified into Hodgkin and Non-Hodgkin Lymphoma (NHL) and can be further subdivided into intranodal or extranodal types. Mucosaassociated lymphoid tissue (MALT) lymphoma represents a low-grade marginal zone B-cell NHL affecting various extranodal sites, such as gastric mucosa, lacrimal and salivary glands [2,3].…”