The authors describe a case of lymphoblastic lymphoma of the renal lodge complicated by hemorrhagic pericarditis, cardiac tamponade and quickly evolved in an unfavourable way. Lymphoblastic lymphoma is classified into lymphocytic lymphomas (or non-Hodgkin) with a higher grade of malignancy. These lymphomas have, in 40% of cases, an initially extra-lymph node localization: among these, the renal or perirenal localization is not very frequent. The concomitant presence of a pericarditis of hemorrhagic type is also less frequent. Unlike Hodgkin's lymphomas, lymphocytic lymphomas are frequently in an advanced stage at the moment of diagnosis, and their evolution is of acute-subacute, often fatal type. The case report is about a 70 year old male, who arrived at the clinical investigation for the subjective presence of asthenia, dyspnea, tachycardia and the objective evidence of jugular turgor, hepatomegaly and distal edemas, hypophonesis of right lung basis, according to a clinical picture of systemic venous congestion which instrumental examinations confirm to be of pericardial origin. The abdominal echographic examination showed an occupation of the perirenal space, so the CAT characterized as a 25 cm long formation (from the renal cavity to pelvis), with a dislocation of close structures. Unfortunately, the clinical picture had a quick evolution towards the exitus for cardiac tamponade, only permitting us a bioptic examination for the diagnosis of the case.