PRIMARY THYMIC MUCOSA‐ASSOCIATED LYMPHOID TISSUE LYMPHOMA: 7 CLINICAL CASES REPORT AND A REVIEW OF THE LITERATURE

Abstract

Introduction: Mucosa-associated lymphoid tissue (MALT) lymphoma is one kind of non-Hodgkin lymphomas (NHL), accounts for 7% to 8%. MALT lymphoma is an indolent, organophilic lymphoma that can nearly occur at any epithelial tissues and mucosal sites. The predilection sites of MALT lymphoma are gastrointestinal tract, salivary glands, lungs and other organs. Studies have shown that MALT lymphoma is associated with chronic inflammation and antigenic stimulation, including chronic infection of pathogens and autoimmune disease. Primary thymus MALT lymphoma is rare. Only 92 cases have been reported over the past 27 years, and only 15 cases reported from China before. Here we introduce 7 cases of primary thymic MALT lymphoma found in the First Affiliated Hospital of Nanjing Medical University, and takes a review of the literature. Methods: We analyze 7 cases of primary thymic MALT lymphoma in the First Affiliated Hospital of Nanjing Medical University from December 2017 to February 2019. We evaluate the clinical features, laboratory test results, PET-CT scans, pathological specimen stained by hematoxylin–eosin (HE) or immunohistochemistry, etc (Figure 1). The median follow-up of 7 cases is 8 months (range 1 to 15 months). Results: primary thymic MALT lymphoma is a kind of indolent small lymphocytic lymphoma, appears mostly in Asian women and is often accompanied with AID. SS is the most common AID. Both contrast-enhanced CT and other imaging findings before surgery and pathological specimen after surgery can see mass with smooth boundary, containing cystic cavities of different sizes and numbers. We can also observe a wide range of small to medium-sized lymphocytes, with increased plasma cells surrounding small blood vessels. Primary thymic MALT lymphoma is lack of API2-MALT1 fusion gene. All cases only received “watch and wait” approach after surgery. Up to now, none of them had recurrence, and their quality of life was no different from normal people. Keywords: Mucosa-Associated Lymphoid Tissue (MALT); positron emission tomography (PET); thyroid function.