and Fan Lin2
(1)
Department of Pathology, Geisinger Health System, Wilkes-Barre, PA, USA
(2)
Department of Laboratory Medicine, Geisinger Health System, Danville, PA, USA
Keywords
Lymph nodeSuppurative lymphadenitisInfectious mononucleosisRosai-Dorfman diseaseGranulomatous lymphadenitisT-cell lymphomaAnaplastic large cell lymphoma (ALCL)Myeloid sarcomaLymphoblastic lymphomaChronic lymphocytic leukemia/small lymphocytic lymphomaSplenic marginal zone lymphomaNodal marginal zone lymphomaFollicular lymphomaMantle cell lymphomaDiffuse large B-cell lymphoma (DLBCL)Plasmablastic lymphomaHodgkin lymphomaNodular lymphocyte-predominant Hodgkin lymphomaNodular sclerosis classical Hodgkin lymphomaLymphocyte-rich classical Hodgkin lymphomaMixed cellularity classical Hodgkin lymphomaLymphocyte-depleted classical Hodgkin lymphomaHistiocytic sarcomaLangerhans cell histiocytosisLangerhans cell sarcomaInterdigitating dendritic cell sarcomaFollicular dendritic cell sarcomaSarcomaCarcinomaMelanomaGerm cell tumort(8;14)(q24;q32)t(11;14)(q13;q32)t(14;18)(q32;q21)t(2;5)(p23;q35)CD20CD79aPAX5CD2CD3CD4CD5CD7CD8CD10CD15CD30EMAIMP3EBVMUM1MYCcCD3CD23BCL2BCL1 (cyclin D1)BCL6LEF1LMO2SOX11TdTALK-1CD38CD138CD1aCD21CD35CD117CD43CD68LysozymeCD34GranzymeMPOZAP-70TIABRAFMYD88EZH2GNA13STAT3IgHSummary of Pearls and Pitfalls
Always attempt to get sufficient sample for flow cytometric study, molecular analysis, and cellblock preparation if a lymphoma is suspected.
A final diagnosis of lymphoma should not be based on cytomorphology alone. Ancillary tests such as flow cytometric study, immunohistochemistry (IHC), and cytogenetic analysis/fluorescence in situ hybridization (FISH) should be performed.
Cell block preparation for immunostains is highly recommended if large B-cell lymphoma (LBCL) is suspected, since a significant number of cases have an inconclusive diagnosis from flow cytometric analysis due to the breakdown of the cytoplasm of lymphoid cells.
Incisional or excisional biopsy is recommended for all cases suspicious for Hodgkin lymphoma , T-cell lymphoma , T-cell-rich B-cell lymphoma, transformation from a low-grade lymphoma into a high-grade non-Hodgkin lymphoma and unusual types of lymphoma.
Culture should be considered when acute inflammation and necrosis are present.
Mycobacterial infection should be considered when a granulomatous process and necrosis are present.
Cohesive sheets and groups of lymphoid cells are frequently seen in an LBCL that might be mistaken for metastatic carcinoma .
Noncaseating granulomas are frequently seen in Hodgkin lymphoma and T-cell lymphoma, in addition to benign conditions and metastatic tumors, such as seminoma.
In addition to Burkitt lymphoma (BL), cytoplasmic vacuoles can be seen in other high-grade lymphomas, rhabdomyosarcoma, seminoma, and carcinomas.
Lymphoglandular bodies are less frequently present in plasmacytoma or myeloid sarcoma .
HIV-associated follicular hyperplasia and mononucleosis are more likely to mimic a high-grade lymphoma.
Collision tumors, such as metastatic small cell carcinoma or melanoma in the background of small lymphocytic lymphoma (SLL), are infrequent, but can be seen.
Most low-grade lymphomas have a mindbomb homolog 1 (MIB-1, Ki-67) proliferative index less than 26%; in contrast, high-grade lymphoma usually has a MIB-1 proliferative index greater than 26%.
2017 WHO Classification of Mature Lymphoid , Histiocytic, and Dendritic Neoplasms 1
Mature B-Cell Neoplasms
Chronic lymphocytic leukemia /small lymphocytic lymphoma (CLL/SLL)
Monoclonal B-cell lymphocytosis2
B-cell prolymphocytic leukemia
Splenic marginal zone lymphoma (MZL )
Hairy cell leukemia
Splenic B-cell lymphoma/leukemia, unclassifiable
Splenic diffuse red pulp small B-cell lymphoma
Hairy cell leukemia variant
Lymphoplasmacytic lymphoma (LPL)
Waldenström macroglobulinemia
Monoclonal gammopathy of undetermined significance (MGUS), IgM2
Mu heavy chain disease
Gamma heavy chain disease
Alpha heavy chain disease
MGUS, IgG/A3
Plasma cell myeloma
Solitary plasmacytoma of the bone
Extraosseous plasmacytoma
Monoclonal immunoglobulin deposition diseases3
Extranodal MZL of mucosa-associated lymphoid tissue (MALT lymphoma)
Nodal MZL
Pediatric nodal MZL
Follicular lymphoma
In situ follicular neoplasia3
Duodenal-type follicular lymphoma3
Pediatric-type follicular lymphoma3
LBCL with interferon regulatory factor 4 (IRF4) rearrangement 3
Primary cutaneous follicle center lymphoma
Mantle cell lymphoma (MCL )
In situ mantle cell neoplasia3
Diffuse large B-cell lymphoma (DLBCL ), not otherwise specified (NOS)
Germinal center B-cell type3
Activated B-cell (ABC) type3
T-cell/histiocyte-rich LBCL
Primary DLBCL of the central nervous system (CNS)
Primary cutaneous DLBCL , leg type
EBV + mucocutaneous ulcer 4
DLBCL associated with chronic inflammation
Lymphomatoid granulomatosis
Primary mediastinal (thymic) LBCL
Intravascular LBCL
ALK-positive LBCL
Plasmablastic lymphoma
Primary effusion lymphoma
Human herpes virus 8 (HHV8)-positive DLBCL , NOS 4
Burkitt lymphoma
Burkitt-like lymphoma with 11q aberration 4
High-grade B-cell lymphoma (HGBCL), with MYC and BCL2 and/or BCL6 rearrangements4
HGBCL, NOS4
B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and CHL
Mature T- and Natural Killer (NK)-Cell Neoplasms
T-cell prolymphocytic leukemia
T-cell large granular lymphocytic leukemia
Chronic lymphoproliferative disorder of NK cells
Aggressive NK-cell leukemia
Systemic EBV + T-cell lymphoma of childhood5
Hydroa vacciniforme-like lymphoproliferative disorder5
Adult T-cell leukemia/lymphoma
Extranodal NK/T-cell lymphoma , nasal type
Enteropathy-associated T-cell lymphoma
Monomorphic epitheliotropic intestinal T-cell lymphoma5
Indolent T-cell lymphoproliferative disorder of the gastrointestinal (GI) tract 5
Hepatosplenic T-cell lymphoma
Subcutaneous panniculitis-like T-cell lymphoma
Mycosis fungoides
Sézary syndrome
Primary cutaneous CD30 -positive T-cell lymphoproliferative disorders
Lymphomatoid papulosis
Primary cutaneous anaplastic large cell lymphoma
Primary cutaneous gamma-delta T-cell lymphoma
Primary cutaneous CD8 -positive aggressive epidermotropic cytotoxic T-cell lymphoma
Primary cutaneous acral CD8 -positive T-cell lymphoma 5
Primary cutaneous CD4 -positive small/medium T-cell lymphoproliferative disorder 5
Peripheral T-cell lymphoma, NOS
Angioimmunoblastic T-cell lymphoma
Follicular T-cell lymphoma 6
Nodal peripheral T-cell lymphoma with T follicular helper (TFH) phenotype 6
Anaplastic large cell lymphoma, ALK positive
Anaplastic large cell lymphoma, ALK negative6
Breast implant-associated ALCL 6
Hodgkin Lymphoma
Nodular lymphocyte-predominant Hodgkin lymphoma
Classical Hodgkin lymphoma (CHL)
Nodular sclerosis CHL
Lymphocyte-rich CHL
Mixed cellularity CHL
Lymphocyte-depleted CHL
Posttransplant Lymphoproliferative Disorders (PTLD )
Plasmacytic hyperplasia PTLD
Infectious mononucleosis PTLD
Florid follicular hyperplasia PTLD6
Polymorphic PTLD
Monomorphic PTLD (B- and T-/NK-cell types)
CHL PTLD
Histiocytic and Dendritic Cell Neoplasms
Histiocytic sarcoma
Langerhans cell histiocytosis (LCH )
Langerhans cell sarcoma
Indeterminate dendritic cell tumor
Interdigitating dendritic cell sarcoma
Follicular dendritic cell sarcoma
Fibroblastic reticular cell tumor
Disseminated juvenile xanthogranuloma
Erdheim-Chester disease7
B Lymphoblastic Leukemia /Lymphoma
B lymphoblastic leukemia/lymphoma, NOS
B lymphoblastic leukemia/lymphoma with recurrent genetic abnormalities
B lymphoblastic leukemia/lymphoma with t(9;22)(q34.1;q11.2); BCR-ABL1B lymphoblastic leukemia/lymphoma with t(v;11q23.3); KMT2A rearranged
B lymphoblastic leukemia/lymphoma with t(12;21)(p13.2;q22.1); ETV6-RUNX1
B lymphoblastic leukemia/lymphoma with hyperdiploidy
B lymphoblastic leukemia/lymphoma with hypodiploidy
B lymphoblastic leukemia/lymphoma with t(5;14)(q31.1;q32.3) IL3-IGH
B lymphoblastic leukemia/lymphoma with t(1;19)(q23;p13.3); TCF3-PBX1
Provisional entity: B lymphoblastic leukemia/lymphoma, BCR-ABL1-like
Provisional entity: B lymphoblastic leukemia/lymphoma with iAMP21
T Lymphoblastic Leukemia/Lymphoma
Provisional entity: early T-cell precursor lymphoblastic leukemia
Provisional entity: NK-cell lymphoblastic leukemia/lymphoma
Nonneoplastic Lymph Nod es
Cytological Features (Fig. 4.1a, b)
High cellularity
Mixed population of lymphoid cells with small lymphocytes predominant
Plasma cells, plasmacytoid cells, and immunoblasts
Histiocytes and tingible-body macrophages
Fig. 4.1
(a, b) Reactive lymph node with a mixed population of lymphoid cells with small lymphocytes predominant on Diff-Quik (a) and Pap stain (b)
Suppurative Lymphadenitis
Cytological Features (Fig. 4.2a, b)
Mixed population of lymphoid cells with a variable number of neutrophils.
Degenerated lymphoid cells, histiocytes, neutrophils, and necrotic debris.
Bacteria or fungus may be seen.
Etiologies could include cat-scratch disease, bacterial infection, lupus, and less commonly Hodgkin lymphoma and metastatic carcinomas.
Fig. 4.2
(a, b) Suppurative lymphadenitis with degenerated lymphoid cells, histiocytes, neutrophils, and necrotic debris on Diff-Quik (a) and Pap stain (b)
Histologic Features
Preserved nodal architecture with lymphoid follicular hyperplasia (Fig. 4.3).
Fig. 4.3
Suppurative lymphadenitis showing preserved nodal architecture with reactive lymphoid follicles and focal abscess formation
Hyperplastic lymphoid follicles show polarity with tingible-body macrophages (Fig. 4.4).
Fig. 4.4
Reactive lymphoid follicles with polarity and tingible-body macrophages
Increased neutrophilic infiltrate, abscess formation, and perilymphadenitis (Fig. 4.5).
Fig. 4.5
Suppurative lymphadenitis with focal abscess formation and necrosis
Infectious Mononucleosis
Cytological Features
Highly cellular specimen
Mixed population of lymphoid cells with many immunoblasts and plasmacytoid cells.
Large atypical lymphoid cells are frequently present; some may mimic Hodgkin cells.
Flow cytometry reveals an abundance of CD8 -positive T cells and only a small population of B cells.
Histologic Features
Preserved nodal architecture with paracortical expansion composed of mixed mature lymphocytes, plasma cells, immunoblasts, and histiocytes in a mottled pattern (Figs. 4.6 and 4.7)
Fig. 4.6
Infectious mononucleosis with reactive lymphoid follicles and perifollicular expansion
Fig. 4.7
Infectious mononucleosis with lymphoblasts and immunoblasts showing prominent nucleoli
Lymphoid follicular hyperplasia
EBV -positive by in situ hybridization stain (Fig. 4.8)
Fig. 4.8
Infectious mononucleosis with positive EBV by in situ hybridization stain
Differential Diagnosis
HGBCL
Hodgkin lymphoma
Rosai-Dorfman Diseas e
Cytological Features
Mixed population of lymphoid cells.
A large number of histiocytes with pale cytoplasm.
Many histiocytes contain lymphoid cells or red blood cells.
These histiocytes are positive for S100, but negative for CD1a .
Tissue biopsy should be recommended for a final diagnosis.
Histologic Features
Marked sinus dilatation with sheets of foamy histiocytes (Figs. 4.9 and 4.10).
Fig. 4.9
Lymph node with Rosai-Dorfman disease shows marked sinus dilation
Fig. 4.10
Lymph node with Rosai-Dorfman disease shows sheets of histiocytes
Some histiocytes may contain lymphocytes, plasma cells, or red blood cells.
Granulomatous Lymphadenitis
Cytological Features (Fig. 4.11a–c)
Mixed population of lymphoid cells.
Epithelioid histiocytes in aggregates with or without multinucleated giant cells.
Necrotic debris and acute inflammatory cells may or may not be present.
Etiologies could include foreign body reaction, sarcoidosis, fungus, mycobacteria, and toxoplasmic lymphadenitis.
Culture should be submitted.
Fig. 4.11
(a–c) Granulomatous lymphadenitis with epithelioid histiocytes in aggregates with or without multinucleated giant cells and a mixed population of lymphoid cells on Diff-Quik (a), Pap stain (b), and cellblock preparation (c)
Histologic Features
Granulomas with necrosis in infection of mycobacteria (Figs. 4.12, 4.13, and 4.14)
Fig. 4.12
Lymph node with caseating granulomas in tuberculosis
Fig. 4.13
Lymph node with caseating granulomas showing necrosis and giant cells
Fig. 4.14
Special stain (acid-fast bacilli [AFB], acid-fast Fite) reveals mycobacteria in caseating granulomas
Granulomas surrounded by few or no lymphocytes (naked granuloma) in sarcoidosis (Figs. 4.15, 4.16, 4.17, and 4.18)
Fig. 4.15
Sarcoidosis in lymph node with noncaseating granulomas
Fig. 4.16
Sarcoidosis in lymph node with “naked” noncaseating granulomas
Fig. 4.17
Sarcoidosis in the spleen with noncaseating granulomas
Fig. 4.18
Sarcoidosis in the spleen with “naked” noncaseating granulomas
Epithelioid granuloma and sheets of monocytoid lymphocytes in infection of Toxoplasma (Figs. 4.19 and 4.20)
Fig. 4.19
Lymph node with toxoplasma shows reactive lymphoid follicles and expanded perifollicular area in a “mottled” appearance
Fig. 4.20
Lymph node with toxoplasma shows cluster of epithelioid histiocytes and monocytoid lymphocytes
Multinucleated cells with foreign body in foreign body granuloma (Fig. 4.21)
Fig. 4.21
Foreign body granuloma with giant cells containing foreign body (arrow)
Non-Hodgkin Lymphoma s
Cytological Features
Hypercellular specimen
A relatively uniform population of lymphoid cells
Can be divided into three groups
Group 1 – small lymphoid cells (smaller than histiocytes), such as small lymphocytic lymphoma (SLL), grade I follicular lymphoma, MZL , LPL
Group 2 –intermediate lymphoid cells (same size as histiocytes), such as MCL , grade II follicular lymphoma, BL, lymphoblastic lymphoma
Group 3 – large lymphoid cells (larger than histiocytes), such as LBCL, grade III follicular lymphoma, ALCL , some T-cell lymphomas
Immunophenotypes of B-cell lymphoma (Table 4.1) and frequent chromosomal translocations and gene mutations (Tables 4.2 and 4.3)
Table 4.1
Immunophenotype of B-cell lymphomas
Category
CD20
CD5
CD10
CD23
BCL1
BCL2
BCL6
LEF1
LMO2
SOX11
SLL
+
+
−
+
−
+
−
+
−
−
FL
+
−
+
−
−
+
+
−
+
−
MZL
+
−
−
−
−
+
−
−
−
−
MCL
+
+
−
−
+
+
−
−
−
+
Table 4.2
Summary of chromosomal translocation-associated lymphomas and the affected genes
Chromosome
Lymphoma
Affected genes
t(8;14)(q24;q32)
BL
c-MYC and IgH
t(11;14)(q13;q32)
MCL
Cyclin D1 and IgH
t(14;18)(q32;q21)
FL
BCL2 and IgH
t(2;5)(p23;q35)
ALCL
ALK and NPM
Table 4.3
Most common gene mutations in non-Hodgkin lymphomas
Lymphoma
Affected genes
Hairy cell leukemia
BRAF V600E
LPL
Waldenström macroglobulinemia
MYD88 L256P
DLBCL , GC type
EZH2 , BCL2 , GNA13
DLBCL , ABC type
MYD88 , CD79A, CARD11, TNFAIP3
Large granular lymphocyte leukemia
STAT3
Small Lymphocytic Lymphoma (SLL)
Clinical Features
Rare before 40 years of age
General lymphadenopathy
Bone marrow involvement
Cytological Features (Fig. 4.22a, b)
Highly cellular
Monotonous population of small lymphocytes
Smooth nuclear membrane, “clock face” nuclear chromatin, small to invisible nucleoli, and scant cytoplasm
Fig. 4.22
(a, b) Small lymphocytic lymphoma with monotonous population of small lymphocytes on Diff-Quik (a) and Pap stain (b)
Histologic Features
Effaced nodal architecture in a vaguely nodular (pseudofollicular) pattern (Fig. 4.23).
Fig. 4.23
Small lymphocytic lymphoma with effaced nodal architecture in a vaguely nodular (pseudofollicular) pattern
Sheets of neoplastic lymphocytes with hypercondensed chromatin and round to slightly irregular nuclear contour (Fig. 4.24).
Fig. 4.24
Small lymphocytic lymphoma cells with hypercondensed chromatin and round nuclear contour; admixed prolymphocytes (arrow) with nucleolus and larger in size
Admixed with prolymphocytes.
Adenopathy <1.5 cm by computed tomography (CT) scan is called tissue-based monoclonal B-cell lymphocytosis.
Immunohistochemistry and Ancillary Studies
Flow cytometry studies: CD19+, CD20 + (low intensity), CD5 +, CD23 +, CD43 +, FMC7- (Fig. 4.25a–d); CD38 and zeta-chain-associated protein kinase 70 (ZAP-70 ) to evaluate the prognosis: both negative, most favorable; one positive and one negative, intermediate; and both positive, least favorable prognosis
Fig. 4.25
(a–d) Flow cytometry studies in small lymphocytic lymphoma shows CD19+ lymphoma cells with coexpression of CD5 and CD23 , positive for CD43 and negative for FMC7
IHC: CD20 +, PAX5 + (especially important after Rituxan treatment that cause CD20 negativity on IHC), CD5 +, CD23 +, lymphoid enhancer-binding factor 1 (LEF1 )+ (Fig. 4.26)
Fig. 4.26
Small lymphocytic lymphoma positive for LEF1
Differential Diagnosis
Reactive lymph node
Other low-grade lymphoma
Follicular Lymphoma
Clinical Features
Accounts for 35% of adult non-Hodgkin lymphomas in the USA and 22% worldwide.
Accounts for 70% of “low-grade” lymphomas in the USA.
Affecting mainly adults, median age of 59 years, rarely occurs before age 20 years.
40% of patients have bone marrow involvement at the initial diagnosis.
Cytological Features (Fig. 4.29a–d)
Usually cellular.
Small lymphocytes with cleaved nuclei.
Papanicolaou (Pap) stain better shows nuclear membrane irregularities.
Small to inconspicuous nucleoli and scant cytoplasm.
Increased numbers of large atypical lymphoid cells (centroblasts) in grade 2 and grade 3 follicular lymphoma.
Grading of follicular lymphoma in a fine needle aspiration (FNA) specimen is similar to that of a histological specimen by counting the number of centroblasts at 40x high-power field (HPF); i.e., grade 1, 0–5 centroblasts/HPF; grade 2, 6–15 centroblasts/HPF; and grade 3, >15 centroblasts/HPF.
MIB-1 (Ki-67) is a useful marker to differentiate most grade 1 and grade 2 from grade 3.
In situ follicular neoplasia with a low rate of progression can be detected by flow cytometry studies in half of the cases. Careful interpretation of FNA specimens is recommended.
Fig. 4.29
(a–d) Follicular lymphoma with increased numbers of large atypical lymphoid cells (centroblasts) in grade 1 (a, b), grade 2 (c), and grade 3 (d) follicular lymphoma
Histologic Features
Effaced nodal architecture in follicular pattern, follicles >75% (Fig. 4.30); in follicular and diffuse pattern, follicles 25–75%; in focally follicular pattern, follicles <25%; and in diffuse pattern, follicles 0%.
Fig. 4.30
Follicular lymphoma with effaced nodal architecture in a follicular pattern as “balls in a bag”
Neoplastic follicles are usually round, surrounded by decreased mantle zone and composed of centrocytes and centroblasts without tingible-body macrophages.
Centrocytes have mature chromatin and folded nuclear membrane; centroblasts show prominent nucleolus and round nuclear contour (Fig. 4.31).
Fig. 4.31
Neoplastic cells (centrocytes) with folded nuclear contour and mature chromatin; admixed centroblasts (arrow) with smooth nuclear membrane and vesicular chromatin
Grades 1–2 (low grade) with similar clinical prognosis
Grade 1: <5 centroblasts/HPF
Grade 2: 6–15 centroblasts/HPF
Grade 3 (high grade): >15 centroblasts/HPF
Grade 3A: centroblasts separated by centrocytes
Grade 3B: sheets of centroblasts
Immunohistochemistry and Ancillary Studies
Flow cytometry: CD19+, CD20 +, CD10 + (Fig. 4.32a–d)
Fig. 4.32
(a–d) Flow cytometry studies of follicular lymphoma with coexpression of CD10 , high intensity of CD20 , and immunoglobulin light chain restriction
IHC: CD20 +, CD10 +, BCL2 +, BCL6 + and LIM-only transcription factor-2 (LMO2 )+ (Fig. 4.33)
Fig. 4.33
Follicular lymphoma with LMO2 positivity
FISH: positive for t(14;18)(q32;q21) (IGH;BCL2) (Fig. 4.34)
Fig. 4.34
FISH in follicular lymphoma with t(14;18) ( IGH; BCL2 ) (1R1G2A, arrow)
Differential Diagnosis
Reactive lymph node
Other low-grade lymphoma
Marginal Zone Lymphoma (MZL )
Clinical Features
Involving nodal and extranodal sites
Commonly in women
Usually in the elderly
Cytological Features (Fig. 4.35a–f)
Cellular smear
A heterogeneous population of cells, including plasmacytoid cells, plasma cells, scattered immunoblasts, centrocyte-like cells
Monocytoid B cells
Fig. 4.35
(a–f) Marginal zone lymphoma with a heterogeneous population of cells, including plasmacytoid cells, plasma cells, scattered immunoblasts, centrocyte-like cells on Diff-Quik (S), and Pap stain (b). Note that immunostain performed on the direct FNA smears showed CD20 positivity (c), Kappa light chain restriction (d), lack of Lambda light chain (e), and low Ki-67 proliferative index (f)
Histologic Features
Expanded marginal zone (Fig. 4.36)
