<prompt> 17-year-old boy presented with complain of petechiae. OE ,sternal tenderness is present. BM biopsy show hypercellularity and more than 20 Lymphoblast. Peripheral smear show TLC and presence of lymphoblast . On X ray. retrosternal mass is seen. All are true about condition patient is suffering except?It has good prognosisNotch gene mutation presentAn immature T-cell phenotype TdtCD34CD7 positiveThymic involvement is seen  <response>: Above patient is most likely suffering from T-cell ALL. Points in our of above diagnosis: Peak at pubey Retrosternal mass More than 20 Lymphoblast Tdt , PAS in BM TLC Lymphoblast present in blood Less common than B cell ALL Thymus Notch gene mutation Gain of function Poor prognosis CD1257 positive Immunophenotyping of immature T-cell phenotype : TdtCD34CD7 positive 