Approach to diagnosis
Standardized criteria to define mediastinal widening are lacking. However, it is considered that tumor less than 30% of the transthoracic diameter are less likely to be symptomatic for SVCS(1). Hence in our study we have considered a mediastinal measurement of >1/3rd the transthoracic distance at the level of the aortic knob on a supine anterior-posterior view x-ray film as mediastinal widening. Hyperleukocytosis was considered as a total leucocyte count more than 100 x 109 /Liter in a patient with leukemia who had respiratory/ neurological symptoms associated with hypoxia secondary to leukocytosis (4).
Flow cytometry was performed on peripheral blood when circulating blasts were present. In their absence, pleural or pericardial fluid was tested by Flow cytometry. Flow cytometry was done using 10 colors, 3 laser BD FACS Lyric/ BD FACS Suite.
Bone marrow examination was done for all patients once they were stable. Those with marrow involvement of ≥ 25% were diagnosed as T-ALL. Bone marrow involvement of <25% or no involvement was diagnosed as T-LBL.