Table 2. Differential diagnosis of classic hairy cell leukemia (HCL) [81].

Characteristic	HCL	HCLv	Splenic marginal zone lymphoma/ splenic lymphoma with villous lymphocytes	B-cell prolymphocytic leukemia	HCL (Japanese variant)	CLL	Splenic diffuse red pulp lymphoma
Morphology	Medium size,  uneven villi,  indistinct  nucleoli	Medium size,  uneven villi,  distinct nucleoli	Small size, polar villi,  small nucleoli	Medium size,  no villi,  prominent  nucleoli	Medium size,  uneven villi,  indistinct  nucleoli	Small size,  smudge  cells, no villi	Small size, villi  present, small  nucleoli
White blood  cell count	Low	High	High	High	High	High	Low
Monocytopenia	Yes	No	No	No	No	No	−
Lymphadenopathy	No	Yes	Yes	Yes	Yes	Yes	Yes
Marker profile
CD25	++	Neg	Neg	Neg	Neg	Neg	Neg
CD103	++	++	Neg	Neg	−	Neg	Neg
CD11c	++	++	+	+	++	+	+
CD123	++	Neg	Neg	Neg	−	+	Neg
CD5	Neg	Neg	Neg	+	Neg	++	Neg
CD23	Neg	Neg	Neg	+	Neg	++	Neg
Annexin-A1	++	Neg	Neg	Neg	−	Neg	Neg
Sox-11	+	−	Neg	−	−	Neg	−
Cyclin D1	+	−	Neg	−	−	Neg	Neg
HCL score	3-4	0-2	0-2	0-2	0-2	0-2	0-2
Histologic findings
Spleen	Red pulp	Red pulp	Marginal	White and  red pulp	Red pulp	White and  red pulp	Red pulp
Bone marrow	Interstitial	Interstitial	Nodular to  intrasinusoidal	Diffuse	Interstitial	Diffuse	Interstitial to  diffuse, absent  pseudosinus