Introduction

Lymphoblastic lymphoma (LBL) is a rare disease which accounts for approximately 2% of all non-Hodgkin lymphomas (NHLs). Most commonly it is of T-cell immunophenotype with about 20% being B cell. LBL is morphologically and immunophenotypically identical to acute lymphoblastic leukemia (ALL). The World Health Organization (WHO) classification of lymphoid neoplasms unifies these entities as precursor T-cell and B-cell lymphoblastic leukemia/lymphoma. In the clinical literature, treatment approaches to LBL and ALL have been parallel but have developed separately. In view of the rarity of LBL and the variable (and arbitrary) clinical distinction between LBL and ALL, reported results have been variable and the optimal treatment approaches remain uncertain.

Clinical presentation

In adults, it is usually diagnosed in males (2:1 ratio), with a peak incidence in the second decade of life. T-cell lymphoblastic lymphoma (T-LBL) typically presents as symptomatic supradiaphragmatic adenopathy. Cough, shortness of breath, and B symptoms are common. A large anterior mediastinal mass can result in respiratory distress and accompanying pleural and pericardial effusions can lead to tracheal obstruction or cardiac tamponade. Bone marrow involvement at presentation is seen in approximately 50% of the patients. Central nervous system (CNS) involvement is variable ranging from 0% to 26% at presentation in different studies and is typically leptomeningeal rather than parenchymal. Hence cytologic evaluation of spinal fluid is recommended in all patients at the time of diagnosis. Primary intra-abdominal adenopathy at presentation is unusual.