Objective: Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL) are clinically and biologically diverse phenotypic diseases amongst hematological malignancies. The current study objectives were to diagnose and classify cases of AL as per revised 4th edition of WHO 2016 classification of AL’s and study their clinicopathological profiles.

Material and Method: This cross-sectional, observational study included 68 patients, diagnosed with AL were recruited. Diagnosis was based on peripheral blood smear examination, bone marrow aspiration, flowcytometry, and cytogenetic and molecular studies.

Results: Sixty-eight cases of AL were diagnosed in a period of 2 years, where 25 cases were of ALL and 43 cases were of AML. In the subclassification of AML as per WHO 2016, 20 cases were of AML, RGA, 21 cases were of AML, NOS, and 2 cases were of AML, MRC. In AML, RGA, APL with PML-RARA positive cases were 10 out of 20 cases, AML with (8;21) RUNX1-RUNX1T1 were 7/20 cases; there were two cases of AML with mutated NPM1 gene and one case of AML with biallelic mutation of CEBPA. In AML, NOS subcategory AML with maturation was more common with 9/21cases. In subcategory of ALL, B-ALL was more common than T-ALL. B-ALL, NOS was more common than B-ALL, RGA and we had 1 case of NK cell Leukemia.

Conclusion: The application of revised 4th edition WHO 2016 classification confers uniformity in reporting acute leukemia cases that aids in the treatment by using targeted therapies and helps in the prediction of prognosis. The WHO classification for acute leukemias is very objective, therapy oriented and the need of the hour.