PART TWO
Diagnostic Cytology
Table 24.1
Differential diagnosis of predominantly small/mixed small and large B cells or small/medium blastoid cells
Cytomorphology
Immunophénotype
Molecular characteristics
Follicular
• Range of cell sizes, as in follicle:
small and large cleaved and large
noncleaved
• Kappa-positive or lambda-positive
or kappa-negative, lambda-negative
• CD19+, CD20+
• CD10+, CD5-, CD23+/-
• BCL6-positive, BCL2-positive
• t(14:18) ^ BCL2 gene
rearrangement is specific but
detection of BCL2 oncoprotein
is not (also in benign hyperpla-
sias, marginal zone lymphoma,
small lymphocytic lymphoma,
Burkitt's lymphoma)
Marginal zone/mucosa-
associated lymphoid tissue
• Predominantly small round cells
with occasional large transformed
cells
• With or without plasmacytoid
• Kappa-positive or lambda-positive
• CD19+ and CD20+
• CD10-, CD5-, CD23-
• BCL6-negative
Splenic B-cell lymphoma
with circulating villous
lymphocytes
• Short thin villi at one pole, clumped
chromatin
• CD11c+ (majority), CD5-, CD10- B cell
lymphoma
• BCL1 and BCL2 gene
rearrangements not detected
Hairy cell leukemia
• Abundant villi, not clustered; fine
chromatin
• CD103+, CD11c+, CD25+ (add if hairy
cell leukemia suspected)
MCL, blastoid variant
• Monomorphic, irregular, small
to medium size
• Lymphoblastoid form or
pleomorphic
• Kappa-positive or lambda-positive
• CD19+ and CD20+
• CD5+, CD10-, CD23-
• BCLl-positive (cyclin Dl-positive in
paraffin), FMC7-positive, CD79a+
• t(11:14) ^ BCL1 gene
rearrangement
Small lymphocytic
lymphoma/
chronic lymphocytic
lymphoma
• Monomorphic, round, small, clumpy
chromatin, occasional prolymphs
(larger cells with nucleoli)
• Kappa-positive or lambda-positive
low intensity
• CD19+/-, CD20 low intensity
• CD5+, CD10-, CD23+, FMC7-negative
• CD38+: worse prognosis
• Zap70-positive: worse prognosis
• Trisomy 12: intermediate
course
• 13q 14 deletions: long survival
• 17p and 11q deletions,
aggressive course
Lymphoplasmacytic
• Mixed population: small lymphs,
plasmacytoid lymphs, plasma cells,
scattered plasmacytoid
immunoblasts— Dutcher bodies
• Kappa-positive or lambda-positive
(cytoplasmic and surface)
• CD5-, CD10-, CD23-, CD20+, and
aberrant
coexpression of CD43
Plasmacytoma/plasma
cell myeloma
• Resemble mature or immature
plasma cells
• No admixture of cells recognizable
as lymphoid
• Cytoplasmic immunoglobulin-positive/
surface immunoglobulin-negative
• LCA (CD45)+/-, CD56+
• B-cell antigen: CD38+, CD138+
Precursor B-lymphoblastic
leukemia/lymphoblastic
lymphoma
• Convoluted or nonconvoluted
small to medium-size fine blast-like
chromatin, inconspicuous nucleoli,
mitoses
• TdT-positive, CD10 (CALLA)+/-, CD45
(LCA)+ in only 80%
• CD19+, CD20+/-
• Surface immunoglobulin-negative
• Cytoplasmic mu chain, CD22+, CD79a+
• Multiple cytogenetic
subgroups
Burkitt's
• Monomorphic, round, medium-size,
coarse chromatin, multiple nucleoli,
abundant cytoplasm/vacuoles on
air-dried smear, mitoses, apoptoses,
tingible body macrophages
• Burkitt-like: larger, more heterogene-
ous, finer chromatin, fewer nucleoli
• Kappa-positive or lambda-positive
• CD10+, CD5-, CD23-
• 99% Ki67 staining
• BCL6-positive, BCL2-negative
• TdT-negative
• c-MYC gene translocation, of
which most are t(8;14)
MCL, mantle cell lymphoma; TdT, terminal deoxynucléotidyl transferase.
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