Table 1.

Pathologic Features of Unclassifiable Splenic Small B-cell Lymphomas

Case	CD5	CD23	CD10	CD43	IgD	Histologic Findings
3	+ (flow)	+	−	NE	+	Diffuse RP involvement by small lymphocytes, atrophic WP (λ-bright, CD20-dim+, FMC7−, CD103, CD11c−, CD25+ by flow cytometry)
6	+	−	−	+	+	WP predominantly CD5 positive small cells with attenuated rim of CD5 negative MZ-type cells
12	−	−	−	−	−	Diffuse RP involvement by small lymphocytes, atrophic WP
13	−	−	−	−	−	Non-MZ-like RP involvement, no WP expansion, light chain restricted plasma cells, lymph node involvement most consistent with MZ lymphoma, also chronic myeloproliferative neoplasm
15	−	−	−	NE	−	Micronodular RP infiltrate of small lymphocytes, atrophic WP
16	+	+	−	+	+	Morphology like SMZL, phenotype more like CLL (κ-intermediate intensity, CD20-dim, FMC7−, CD38+ by flow cytometry)
23	−	−	−	−	+	Mostly MZ-like cells but extensive RP involvement, WP also involved but not expanded
24	−	−	−	−	NE	All small lymphs with both WP and RP involvement
28	−	−	−	−	−	All small lymphs with both WP and RP involvement
32	−	−	−	NE	NE	Lymphoplasmacytic RP nodules with epithelioid histiocyte clusters, no WP involvement, LN consistent with lymphoplasmacytic lymphoma - favor lymphoplasmacytic lymphoma*
36	−	−	−	−	+	Plasmacytoid cells with no MZ-like cells but expanded WP
37	−	−	−	−	−	All small lymphs with both WP and RP involvement
38	−	−	−	+	+	WP with large cells including MZ-like cells, transformed cells, and angulated cells surrounded by a rim of small cells
40	−	−	−	NE	+	All small lymphs with both WP and RP involvement
43	−	−	−	−	+	Small lymphs with extensive RP involvement but focally prominent WP
44	−	−	−	−	−	Small lymphs with extensive RP involvement but focally prominent WP

NE = Not evaluable, WP= white pulp, RP=red pulp, lymphs=lymphocytes

^*This patient had an IgM kappa paraprotein, cold agglutinin disease and marrow involvement.