We report the case of a 63 year-old female who presented with a seven-year history of epigastric pain and a sudden overall deterioration. Gastroscopy demonstrated inflammatory aspect and ulceration in the antrum and fundus. Histology showed a lymphocytic infiltrate consistent with low grade mucosa-associated lymphoid tissue lymphoma and cytomegalovirus gastritis. There was no evidence of Helicobacter pylori infection. Other investigations demonstrated two pulmonary foci consistent with lymphomatous infiltration and a reduced CD4 + T-lymphocyte count (85/mm3). Other screening tests including HIV serology were negative. This case of idiopathic CD4 lymphopenia, in conjunction with the other rare cases in the literature, allows us to reevaluate this condition and its unusual clinical presentation with two opportunistic pathologies.