C91.5Adult T-cell lymphoma/leukemia (HTLV-1-associated)

C91.5 is the ICD-10-CM diagnosis code for adult T-cell lymphoma/leukemia (HTLV-1-associated). It belongs to category C91 (lymphoid leukemia), block C81-C96 (malignant neoplasms of lymphoid, hematopoietic and related tissue) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within C91 (lymphoid leukemia), C91.5 is specifically for adult T-cell lymphoma/leukemia (HTLV-1-associated). Related codes cover acute lymphoblastic leukemia [ALL] (C91.0), chronic lymphocytic leukemia of B-cell type (C91.1), Prolymphocytic leukemia of B-cell type (C91.3), Hairy cell leukemia (C91.4), Prolymphocytic leukemia of T-cell type (C91.6), unspecified (C91.9), mature B-cell leukemia Burkitt-type (C91.A) and other lymphoid leukemia (C91.Z).

To report this condition, pick the subcode that matches the documentation: C91.50 (not having achieved remission), C91.51 (in remission) and C91.52 (in relapse).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.