Table 1.

Diagnostic criteria and classification (the Shimoyama classification).

	Smoldering	Chronic	Lymphoma	Acute
Anti-HTLV-I antibody	+	+	+	+
Lymphocyte (×109/L)	<4	≥4 †	<4	*
Abnormal T lymphocytes	≥5%	+‡	≤1%	+‡
Flower cells with T-cell marker	Occasionally	Occasionally	No	+
LDH	≤1.5 N	≤2 N	*	*
Corrected Ca2+ (mEq/L)	<5.5	<5.5	*	*
Histology-proven lymphadenopathy	No	*	+	*
Tumor lesion
Skin	§	*	*	*
Lung	§	*	*	*
Lymph node	No	*	Yes	*
Liver	No	*	*	*
Spleen	No	*	*	*
Central nervous system	No	No	*	*
Bone	No	No	*	*
Ascites	No	No	*	*
Pleural effusion	No	No	*	*
Gastrointestinal tract	No	No	*	*

HTLV-I, human T-lymphotropic virus type-I; LDH, lactate dehydrogenase; N, normal upper limit. * No essential qualification except terms required for other subtype(s); ^† Accompanied by T-lymphocytosis (3.5 × 10⁹/L or more); ^‡ In case abnormal T-lymphocytes are less than 5% in peripheral blood, histology-proven tumor lesion is required; § No essential qualification if other terms are fulfilled, but histology-proven malignant lesion(s) is required in case abnormal T-lymphocytes are less than 5% in peripheral blood.