Comparison of working formulation and REAL classification of non-Hodgkin’s lymphoma: an analysis of 52 cases

Figures & data

Figure 1. A panel of photomicrographs depicting various non-Hodgkin lymphomas according to the Working Formulation: (a) malignant lymphoma (ML) small lymphocytic (H&E, ×100); (b) ML follicular predominantly small cleaved cells (H&E, ×100); (c) ML follicular predominantly large cells (H&E, ×100); (d) ML diffuse large cell (H&E, ×100); (e) ML lymphoblastic (H&E, ×100); and (f) ML diffuse mixed small and large cells (H&E, ×100).

Figure 2. Immunohistochemical photomicrographs showing a case of T cell-rich B-cell lymphoma with large cells positive for CD20 (a, ×200) and small lymphocytes in the background staining for CD45RO (b, ×200). Another case of lymphoma (diffuse mixed small and large by Working Formulation) showing negative staining for CD20 (c, ×100) and diffuse positive staining for CD45RO (d, ×100), suggestive of T-cell lymphoma.

Table 1. Classification of NHL cases based on Working Formulation

	Diagnosis	No. of cases	Percentage (%)
I	Low grade
a	ML, small lymphocytic consistent with CLL	7	13·46
b	ML, follicular predominantly small cleaved cell	5	9·61
c	ML, follicular, mixed, small cleaved and large cell	1	1·92
II	Intermediate grade
a	ML, follicular predominantly large cell	3	5·76
b	ML, diffuse small cleaved cell	7	13·46
c	ML, diffuse, mixed, small and large cell	11	21·15
d	ML, diffuse large cell	13	25
III	High grade
a	ML, large cell immunoblastic	0	0
b	ML, lymphoblastic	5	9·61
c	ML, small non-cleaved cell Burkitt’s	0	0
IV	Miscellaneous
a	Composite	0	0
b	Mycosis fungoides	0	0
c	Histiocytic	0	0
d	Extramedullary plasmacytoma	0	0
e	Unclassifiable	0	0
f	Other	0	0
	Total	52	100%

Table 2. Classification of non-Hodgkin’s lymphoma cases based on REAL classification

	Diagnosis	No. of cases	Percentage (%)
	B-cell neoplasms
I	Precursor B-cell lymphoblastic lymphoma	1	1·92
II	Peripheral B-cell neoplasms
1	B-cell small lymphocytic lymphoma	6	11·53
2	Lymphoplasmacytoid lymphoma	0	0
3	Mantle cell lymphoma	1	1·92
4	Follicle center lymphoma, follicular/diffuse	17	32·69
	Grade 1 (9 cases)
	Grade 2 (1 case)
	Grade 3 (7 cases)
5	Marginal zone B-cell lymphoma	2	3·84
6	Diffuse large B-cell lymphoma	13	25
7	Plasmacytoma	0	0
8	Burkitt’s lymphoma	0	0
	T-cell neoplasms
I	Precursor T-cell lymphoblastic lymphoma	4	7·7
II	Peripheral T-cell lymphomas
1	T-cell chronic lymphocytic lymphoma	1	1·92
2	Mycosis fungoides/Sezary syndrome	0	0
3	Peripheral T-cell lymphomas	5	9·61
4	Angioimmunoblastic T cell lymphoma	0	0
5	Angiocentric lymphoma	0	0
6	Intestinal T-cell lymphoma	1	1·92
7	Adult T-cell lymphoma	0	0
8	Anaplastic T-cell lymphoma	1	1·92
	Total	52	100%

Table 3. Diagnosis of NHL before and after Immunohistochemistry

	Diagnosis before IHC (Working Formulation)	Diagnosis after IHC (REAL classification)
I	Low grade
A	ML, small lymphocytic consistent with CLL (n = 7)	B-cell SLL (n = 6)
		T-cell SLL (n = 1)
B	ML, follicular predominantly small cleaved cell (n = 5)	B-cell NHL, follicle center lymphoma, Grade 1 (n = 4)
		B-cell NHL, follicle center lymphoma, Grade 2 (n = 1)
C	ML, follicular mixed small cleaved & large cell (n = 1)	B-cell NHL, follicle center lymphoma, Grade 1 (n = 1)
II	Intermediate grade
A	ML, follicular predominantly large cell (n = 3)	B-cell NHL, follicle center lymphoma, Grade 3 (n = 3)
B	ML, diffuse small cleaved cell (n = 7)	B-cell NHL, follicle center lymphoma, Grade 1 (n = 3)
		B-cell NHL, follicle center lymphoma, Grade 3 (n = 1)
		B cell, marginal zone lymphoma (n = 2)
		B cell, mantle cell lymphoma (n = 1)
C	ML, diffuse mixed small and large cell (n = 11)	B-cell NHL, diffuse large cell lymphoma (DLBCL, n = 3)
		B-cell NHL, diffuse follicle cell lymphoma, Grade 3 (n = 3)
		B-cell NHL, diffuse follicle center lymphoma, Grade 1 (n = 1)
		T-cell NHL, peripheral T-cell lymphoma (n = 3)
		T-cell NHL, anaplastic large cell lymphoma (n = 1)
D	ML, diffuse large cell (n = 13)	B-cell NHL, diffuse large cell lymphoma (DLBCL, n = 10)
		T-cell NHL, peripheral T-cell lymphoma (n = 2)
		T-cell, intestinal lymphoma (n = 1)
III	High grade
A	ML, large cell immunoblastic (n = 0)
B	ML, lymphoblastic (n = 5)	T cell, lymphoblastic lymphoma (n = 4)
		B cell, lymphoblastic lymphoma (n = 1)
C	ML, small cell non-cleaved Burkitt’s (n = 0)
IV	Miscellaneous
	Miscellaneous (n = 0)
	Total	52 cases