We report the case of a 64 year old male patient with a history of ischemic heart disease who underwent surgery for an abdominal mass. The histological diagnosis was highly malignant non-Hodgkin's lymphoma. After surgery the patient was admitted to our Department and received 6 courses of chemotherapy according to the COP schedule, followed by radiotherapy to the left upper abdominal region and ipsilateral lung base. The patient achieved partial remission. One month later he began to complain of left axillary lymphadenomegaly, polydipsia and polyuria. A NMR brain scan showed a hypophyseal mass. The patient was treated with DDAVP and chemotherapy with the PRO-MACE protocol; the polyuria and lymphadenomegaly disappeared and the size of the hypophyseal mass reduced markedly. The clinical picture was, therefore, attributed to a hypophyseal localization of the non-Hodgkin's lymphoma, which is a very rare manifestation of lymphomatous spread to the central nervous system. Our case is also interesting because it shows that a favorable outcome can be obtained with chemotherapy, provided that the latter is sufficiently aggressive. This is not necessarily the case with radiotherapy which may also be followed by late and severe neurologic sequelae.