<prompt> Extranodal marginal zone MALT lymphomas can involve thymus in the setting of:HIVSLESjogrens syndromeCrohns disease  <response>: Extranodal marginal zone MALT lymphomas It involve the thymus in the setting of Sjogrens syndrome or other autoimmune disorders The lymphoma cells often express IgA instead of IgM on their surface. Other tumors that involve thymus: Castlemans disease Germ cell tumors Carcinoid tumors thymoma. Ref: Harrison, E-18, Chapter e-20. 