Primary mucosa-associated lymphoid tissue lymphoma of the liver: A report of two cases and review of the literature.

Mucosa-associated lymphoid tissue (MALT) lymphoma of the liver is a very rare condition and thus the diagnosis may be challenging. The clinical presentation is usually variable, ranging from minimal clinical symptoms to severe end stage liver disease. In this paper, we describe the clinicopathologic findings in two cases of primary hepatic MALT lymphoma. One case is an 80-year-old female with no underlying chronic liver disease and the second case is a 30-year-old female with autoimmune hepatitis complicated by MALT lymphoma. In both specimens, there was diffuse infiltration of atypical B-lymphocytes that were positive for CD20 and CD79a, but negative for CD5, CD43 and CD10. There were occasional lymphoepithelial lesions involving the hepatocytes or bile ducts. Polymerase chain reaction analysis showed monoclonal immunoglobulin heavy chain gene rearrangement in both cases. The first case was treated with surgery but developed pulmonary recurrence a year after complete resection but went into remission following treatment with rituximab. A second recurrence occurred in the right parotid gland 7 years later, which was treated with idelalisib. The second case was effectively treated with rituximab. To our knowledge, the second case is the first reported case linked to autoimmune hepatitis.