A 17 year old boy presented with total count of 138 x 109 /L with 80% blasts on the peripheral smear. Chest X-ray demonstrated a large mediastinal mass. Immunophenotyping of this patient's blasts would most likely demonstrate:: (A) No surface antigens (null phenotype), (B) An immature T cell phenotype (Tdt/D34/CD7 positive), (C) Myeloid markers, such as CD13, CD33 and CD15, (D) B cell markers, such as CD19, CD20 and CD22
Answer is B. . An immature I$? cell phenotype (Tdt/D34/CD7 positive)