Table 1.

Clinical classification of adult T-cell leukemia/lymphoma.4, 7

Forms	Lymphocytosis	Abnormal lymphocytes (%)	LDH levels	Hypercalcemia	Involved organs
Smolderinga	Absent	<5 or ≥5	≤1.5 × N	Absent	With or without skin/lung lesions
PCT	Absent	<5	≤1.5 × N	Absent	Skin
Chronicb	Present	Present	≤2 × N	Absent	Any organ except bone, GIT and CNS
Lymphoma	Absent	≤1	Variable	May occur	Lymph nodes and any other organ
Acute	Usually present	≥5	>1.5 × N	May occur	Any organ

^aSubtyped into leukemic (≥5%) and non-leukemic (<5%) according to abnormal lymphocytes percentage.

^bSubtyped into favorable and unfavorable according to the serum levels of albumin, urea nitrogen, and lactic dehydrogenase (LDH).

PCT: primary cutaneous tumoral; N: normal value; GIT: gastrointestinal tract; CNS: central nervous system.