Diagnostic criteria for NHL

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Chronic lymphatic leukaemia/small lymphocytic lymphoma (CLL/SLL)

Incidence: 7-8% of all NHL.
Cytology: Smears show monotonous, dispersed cell populations composed of small lymphocytes with clumped chromatin and occasional, small, nucleoli; mitoses are absent or rare. Accelerate phases of CLL/SLL show larger, nucleolated, cells (paraimmunoblasts) and mitoses, and should not be confused with Richters syndrome, which is a large-cell histiocytic lymphoma arising on a CLL/SLL background.
ICC: light chain restriction, CD5+, CD20+, CD23+; Ki 67 is positive in a small percentage of the cells.
FC: CD5/CD19+, CD19/CD23+, CD19+/CD10-, ? or ? light chain restriction.
FISH: trisomy 12, 11q22 (ATM), 12, 13q14.3, 13q34.3 (LAMP1), and 17p13.1 (p53) as prognostic markers.
Differential diagnosis: Non-specific hyperplasia ML, FL, MZL.

CLL/SLL: A monotonous monomorphous cell population of small lymphocytes with clumped chromatin and occasional, small, nucleoli.

CLL/SLL: A monotonous monomorphous cell population of small lymphocytes with clumped chromatin and occasional, small, nucleoli.

SLL/CLL smears shows a monomorphic, dispersed cell population composed by small lymphocytes and occasional larger nuclei. Small cytoplasm fragments (glandular bodies) are present in the background.

ICC of SLL/CLL on cytospins showing negativity for lambda and positivity for kappa light chains (peroxidase/anti peroxidase immunostain)

ICC of SLL/CLL on cytospins showing negativity for lambda and positivity for kappa light chains (peroxidase/anti peroxidase immunostain)

CLL/SLL: FNA smear and corresponding FC showing CD19/CD5 and CD19/CD23 co-expression and kappa light chain restriction.

CLL/SLL: FNA smear and corresponding FC showing CD19/CD5 and CD19/CD23 co-expression and kappa light chain restriction.

Lymphoplasmacytoid Lymphoma, Immunocytoma (LPCL)

Incidence: 1-2% of all NHL.
Cytology: dispersed cell population composed of small lymphocytes with plasmacytoid differentiation; mature plasma cells are also present.
ICC: CD20+, CD5-,CD10-, CD23-, Ki67+ in a variable percentage (10-20%) of cells.
FC: CD5-/CD19+, CD19+/CD23+, CD19+/CD10-, CD19+/CD38+, ? or ? light chain restriction.
Differential diagnosis: Non-specific hyperplasia, SLL/CLL.

LPCL dispersed cell population composed by small lymphocytes with clumped chromatin and plasmacytoid differentiation

LPCL dispersed cell population composed by small lymphocytes with clumped chromatin and plasmacytoid differentiation

LPCL dispersed cell population composed by small lymphocytes with clumped chromatin and plasmacytoid differentiation

LPCL FC showing co-expression of CD19/CD23, CD19/FMC7, CD19/CD38 and light chain restriction.

Mantle cell lymphoma (MCL)

Incidence: 7-10% of all NHL.
Cytology: dispersed cell population composed of small/medium-size lymphocytes with irregular nuclei and a thin rim of pale cytoplasm. Nuclei may have slightly irregular shape, clumped chromatin and small nucleoli, or may be cleaved. Mitoses are scanty whereas they may be numerous in the blastoid variant
ICC. CD20+, CD5+,CD10-, CD23-, Ki67+ in a variable percentage (10-20%) of the cells.
FC: CD5+/CD19+, CD19/FMC7+, CD19+/CD23-, CD19+/CD10-, ? or ? light chain restriction.
FISH: t(11;14)(q13;q32).
Differential diagnosis: Non-specific hyperplasia, SLL/CLL,FL, MZL.

MCL: dispersed cell population composed by medium-size lymphocytes. Nuclei may be slightly irregular in shape or cleaved and have clumped chromatin and small nucleoli.

MCL: dispersed cell population composed by medium-size lymphocytes. Nuclei may be slightly irregular in shape or cleaved and have clumped chromatin and small nucleoli.

MCL: dispersed cell population composed by medium-size lymphocytes. Nuclei may be slightly irregular in shape or cleaved and have clumped chromatin and small nucleoli.

MCL: dispersed cell population composed by medium-size lymphocytes with irregular nuclei. Nuclei are slightly irregular in shape or cleaved and have clumped chromatin and small nucleoli.

MCL: nuclear positivity for cyclin D1.

MCL: Medium-size lymphocytes with irregular nuclei and clumped chromatin. Frequent mitoses may be seen.

MCL: Ki67 immunostain may shows nuclear positivity in a high percentage of cells.

MCL: Medium-size lymphocytes with irregular nuclei and clumped chromatin. Nuclei may show a kind of moulded pattern.

MCL: FISH demonstration of t(11;14)(q13;q32): locus 14q32 (IGH) is labelled in green and locus 11q13 (CNDD1/PRAD1) is labelled in orange. Note fusion signals (yellow) in which the green signals overlap the orange signals.

FC of MCL showing CD19/CD5 and CD19/FMC7 co-expression and lambda light chain restriction.

Follicular lymphoma (FL)

Follicular lymphoma (FL): cytology

Incidence: 22-30% of all NHL.
Cytology: dispersed cell population composed of a spectrum of medium- to large-size lymphocytes, with irregular nuclei and a thin rim of pale cytoplasm. Nuclei may have slightly irregular shape, or be cleaved with clumped chromatin and inconspicuous nucleoli in grade I, to large nuclei with dispersed chromatin and two or more marginal nucleoli in grades II and III.
ICC: CD20+,CD5-,CD10+,CD23-,Ki67+ in a variable percentage of the cells.
FC: CD5-/CD19+, CD19+/FMC7+, CD19+/CD23-, CD19+/CD10+, CD10/bcl-2+, ? or ? light chain restriction.
FISH: t(14;18)(q32;q21).
Differential diagnosis: Non-specific hyperplasia, SLL/CLL,MCL.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: Ki-67 show positivity in a relative small percentage of the cells.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: a monotonous population of small lymphocytes with clumped chromatin and inconspicuous nucleoli. Scattered large cells are present in the background.

Low-grade FL: Ki-67 show positivity in a relative small percentage of the cells.

Intermediate-grade FL: a relative monomorphous population of medium-sized lymphocytes with clumped chromatin, nuclear abnormalities and one or more nucleoli.

Intermediate-grade FL: a relative monomorphous population of medium-sized lymphocytes with clumped chromatin, nuclear abnormalities and one or more nucleoli.

Intermediate-grade FL: Ki-67 show positivity in a large percentage of the cells.

High-grade FL: a relative monomorphous population of large lymphoid cells with dispersed chromatin, nuclear abnormalities and one or more large nucleoli.

High-grade FL: a relative monomorphous population of large lymphoid cells with dispersed chromatin, nuclear abnormalities and one or more large nucleoli.

High-grade FL: Ki-67 show positivity in almost all the large cells present in the smear.

High-grade FL: a relative polymprphous population of large lymphoid cells with dispersed chromatin, nuclear abnormalities and one or more large nucleoli. Scattered small lymphocytes are present in the background.

High-grade FL: a relative polymprphous population of large lymphoid cells with dispersed chromatin, nuclear abnormalities and one or more large nucleoli. Scattered small lymphocytes are present in the background.

Follicular lymphoma (FL): flow cytometry

FC of FL showing CD19/CD10 co-expression, bcl-2 overexpression and kappa light chain restriction.

FC of FL showing CD19/CD10 co-expression, bcl-2 overexpression and kappa light chain restriction.

FC of FL showing CD19/CD10 co-expression, bcl-2 overexpression and kappa light chain restriction.

FL: a relative polymorphous population of medium-sized lymphocytes with dispersed chromatin, nuclear abnormalities,
and one or more small nucleoli. FC shows CD10/bcl-2 co-expression that reflects the follicles bcl-2 histological positivity.

FL: a relative polymorphous population of medium-sized lymphocytes with dispersed chromatin, nuclear abnormalities,
and one or more small nucleoli. FC shows CD10/bcl-2 co-expression that reflects the follicles bcl-2 histological positivity.

FL: a relative polymorphous population of medium-sized lymphocytes with dispersed chromatin, nuclear abnormalities,
and one or more small nucleoli. FC shows CD10/bcl-2 co-expression that reflects the follicles bcl-2 histological positivity.

FL: a relative polymorphous population of medium-sized lymphocytes with dispersed chromatin, nuclear abnormalities,
and one or more small nucleoli. FC shows CD10/bcl-2 co-expression that reflects the follicles bcl-2 histological positivity.

Follicular lymphoma (FL): FISH

In cases of FL (CD10/19 co-expression) with dim or no light chains expression, FISH may be helpful in diagnosis by the demonstration of t14-18. Bcl2 locus (18q21,labelled red), overlaps IGH locus (14q32, labelled in green) giving a signal of fusion (yellow).

IGH gene rearrangement in lymphoma with dim or no light chains expression

FC in a lymphoma without light chains expression

Detection of clonal IGH gene rearrangements: In PCR, rearranged DNA is amplified with a series of consensus primers that are complementary to sequences of variable regions framework 1, framework 2, and framework 3 and to joining regions (JH) of the IGH gene. Monoclonal and polyclonal PCR products can be discerned by their size distributions. There are several methodologies for evaluating PCR amplifications; here conventional electrophoresis in ethidium bromidestained agarose gels (AGE). If a significant population of cells contains the same unique IGH rearrangement, it appears as a well-defined band on each of the AGE here reported. A clonal population of cells is indicated by the presence of a distinct nongermline band, whereas normal or reactive populations have only germline bands and should produce multiple bands (smears).

Marginal Zone B-cell Lymphoma (MZL)

Incidence: 2-3% of all NHL.
Cytology: dispersed cell population composed of small lymphocytes with irregular nuclei. Nuclei may have slightly irregular shape, dense chromatin and indistinct nucleoli, or be cleaved. The rim of pale cytoplasm observed in histological sections is rare or undetectable on the smears. Monocytoid cells and plasma cells may be intermingled, mitoses are scanty.
ICC: CD20+, CD5-,CD10-, CD23-, Ki67+/-.
FC: CD5-/CD19+, CD19+/FMC7-, CD19+/CD23-, CD19+/CD10-, ? or ? light chain restriction.
Differential diagnosis: Non-specific hyperplasia, SLL/CLL,MCL, FL.

MZL: ultrasound guided FNC of the spleen with diffuse splenomegaly (note the tip of the needle). FNC shows a relative monomorphous population of small lymphocytes with clumped chromatin. FC shows CD5-, CD10-,kappa light chain restriction with CD19/kappa co-expression.

MZL: ultrasound guided FNC of the spleen with diffuse splenomegaly (note the tip of the needle). FNC shows a relative monomorphous population of small lymphocytes with clumped chromatin. FC shows CD5-, CD10-,kappa light chain restriction with CD19/kappa co-expression.

MZL: ultrasound guided FNC of the spleen with diffuse splenomegaly (note the tip of the needle). FNC shows a relative monomorphous population of small lymphocytes with clumped chromatin. FC shows CD5-, CD10-,kappa light chain restriction with CD19/kappa co-expression.

MZL: ultrasound guided FNC of the spleen with diffuse splenomegaly (note the tip of the needle). FNC shows a relative monomorphous population of small lymphocytes with clumped chromatin. FC shows CD5-, CD10-,kappa light chain restriction with CD19/kappa co-expression.

Extranodal B-cell lymphoma of mucosa associated lymphoid tissue (MALT)

MALT lymphoma: ultrasound guided FNC of an extremely thick bowel wall with former inconclusive endoscopic biopsies. FNC shows atypical lymphoid cells in a necrotic background. FC shows CD5- and kappa light chain restriction.

MALT lymphoma: ultrasound guided FNC of an extremely thick bowel wall with former inconclusive endoscopic biopsies. FNC shows atypical lymphoid cells in a necrotic background. FC shows CD5- and kappa light chain restriction.

MALT lymphoma: ultrasound guided FNC of an extremely thick bowel wall with former inconclusive endoscopic biopsies. FNC shows atypical lymphoid cells in a necrotic background. FC shows CD5- and kappa light chain restriction.

MALT lymphoma: ultrasound guided FNC of an extremely thick bowel wall with former inconclusive endoscopic biopsies. FNC shows atypical lymphoid cells in a necrotic background. FC shows CD5- and kappa light chain restriction.

Diffuse large B-cell lymphoma (DLBCL)

Incidence: 30-40% of all NHL.
Cytology: dispersed cell population composed of large lymphoid cells with irregular nuclei, one or more large nucleoli and a wider rim of pale cytoplasm. Morphological variants of DLBCL are centroblastic, immunoblastic T-cell/histiocyte-rich and anaplastic. Nuclei may be slightly irregular in shape or cleaved and have dense chromatin and indistinct nucleoli. Lymphocyte and plasma cells may be intermingled, Mitoses are scanty.
ICC: CD19+, CD20+, 22+, CD79a+, Ki67+ in a variable percentage (10-20%) of the cells.
FC: CD5-/CD19+, CD19+/FMC7-, CD19+/CD23-, CD10-, ? or ? light chains restriction.
DD: HL, metastases.

DLBCL: dispersed cell population composed by large lymphoid cells with irregular nuclei, one or more large nucleoli. Scatterd small lymphocytes are present in the background.

DLBCL: dispersed cell population composed by large lymphoid cells with irregular nuclei, one or more large nucleoli. Scatterd small lymphocytes are present in the background.

DLBCL: ICC:CD20+.

Caption here

DLBCL: dispersed cell population composed by large lymphoid cells with irregular nuclei, one or more large nucleoli, immature chromatin and nuclear crushes. Cytoplasm may be present or not.

Plasma cell myeloma/plasmacytoma

Incidence: 15% of haematological malignancies.
Cytology: in typical cases show dispersed cell population composed of small/medium-size plasma cells. Cells show one or two nuclei with clumped cartwheel chromatin and small nucleoli. Cytoplasm, when present are well defined with evident perinuclear Golgi apparatus. In poorly differentiated cases nuclei are atypical and may show marked anisonucleosis.
ICC. CD20-/+, CD5-, CD10-, CD23-, CD38, CD79a, EMA, Ki67+ in a variable percentage.
FC: CD38+, CD38/56 +/-, CD10-, ? or ? light chain restriction.
Differential diagnosis: non-haematological tumours in poorly differentiated cases.

Extramedullary plasmacytoma shows a dispersed cell population of small and medium size plasma cells. Cells show one or two nuclei with clumped cartwheel chromatin and small nucleoli. Cytoplasm, when present are well defined with evident perinuclear Golgi apparatus. Note binucleated cells.

Extramedullary plasmacytoma shows a dispersed cell population of small and medium size plasma cells. Cells show one or two nuclei with clumped cartwheel chromatin and small nucleoli. Cytoplasm, when present are well defined with evident perinuclear Golgi apparatus. Note binucleated cells.

FC of Plasma cell myeloma/plasmacytoma showing CD19-, CD38+, CD38/56 co-expression is observed in 70-80% of the cases multiple myeloma. Lack of CD56 expression has been considered a negative prognostic factor.

FC of Plasma cell myeloma/plasmacytoma showing CD19-, CD38+, CD38/56 co-expression is observed in 70-80% of the cases multiple myeloma. Lack of CD56 expression has been considered a negative prognostic factor.

Burkitt lymphoma (BL)

Incidence: 1-2% of all NHL.
Cytology: dispersed cell population composed of undifferentiated medium sized lymphocytes with dispersed chromatin and one or more small basophilic nucleoli; the cytoplasm is basophilic and sometimes vacuolated. Immature nuclei are fragile, resulting in frequent nuclear crushes in the smear; a high mitotic index is observed. Scattered macrophages with engulfed cytoplasm may give a starry sky pattern to the smear.
ICC: CD20+, CD5-, CD10+, Bcl-6+, CD23-, Ki67+ in a high percentage of the cells.
FC: CD5-/CD19+, CD19+/FMC7-, CD19+/CD23-, CD19+/CD10+, light chain often unexpressed.
FISH: t(8;14)(8q24;q32).

BL: dispersed cell population composed by undifferentiated medium sized lymphocytes with dispersed chromatin and one or more small basophilic nucleoli; Immature nuclei are fragile resulting in frequent nuclear crushes in the smear; an high mitotic index is observed. Scattered macrophages with engulfed cytoplasm may give a starry sky pattern to the smear.

BL: dispersed cell population composed by undifferentiated medium sized lymphocytes with dispersed chromatin and one or more small basophilic nucleoli; Immature nuclei are fragile resulting in frequent nuclear crushes in the smear; an high mitotic index is observed. Scattered macrophages with engulfed cytoplasm may give a starry sky pattern to the smear.

BL: dispersed cell population composed by undifferentiated medium sized lymphocytes with immature chromatin. Numerous mitoses may be observed. FC: almost all the cells shows CD19/CD10 co-expression.

BL: dispersed cell population composed by undifferentiated medium sized lymphocytes with immature chromatin. Numerous mitoses may be observed. FC: almost all the cells shows CD19/CD10 co-expression.

Anaplastic large cell lymphoma

Incidence: 3% of all NHL.
Cytology: dispersed and polymorphous large cells with very irregular shape. Multilobated, horseshoe bi- and multinuclecleated cells are present. The nuclei have coarse chromatin and larger nucleoli.
Background is generally polymorphous with mature lymphocytes, granulocytes and eosinophils. Atypical mitoses and necrosis may be seen.
ICC: CD20-, CD45+ CD15-, CD30++, Ki67+, EMA+, ALK-1+/-.
FC: CD5+/-, CD19+/-, aberrant phenotypes may be observed.
FISH: t(2;5)(p23;q35).
PCR: clonal rearrangement of the T-cell receptor (90%).
Differential diagnosis: DLBCL, HL, metastases.

Large anaplastic, nucleolated cells, Ki67+ with small lymphocytes and granulocytes in the background.

Large anaplastic, nucleolated cells, Ki67+ with small lymphocytes and granulocytes in the background.

Large anaplastic, nucleolated cells, Ki67+ with small lymphocytes and granulocytes in the background.

Large anaplastic, nucleolated cells, Ki67+ with small lymphocytes and granulocytes in the background.

Large anaplastic, nucleolated cells, 30+ interspersed between small lymphocytes

Peripheral T-cell lymphoma (PTL)

Incidence: 7-8% of all the NHL.
Cytology: dispersed and polymorphous medium- or large-sized cells with irregular shape, vesicular nuclei and evident nucleoli. The nuclei have irregular shape, coarse chromatin and one or more large nucleoli. Binucleated cells are frequently observed. The background is generally polymorphous; mature lymphocytes, granulocytes, numerous eosinophils may be present.
ICC: CD20-, CD3+, CD4+ CD10-, CD23-, Ki67+ in a variable percentage of the cells.
FC: CD5+, CD19-, CD10-, CD2+ CD3+ CD7-.
PCR: TC receptor rearranged in most cases.
Differential diagnosis: B-cell NHL.

PTL shows a wide spectrum of cytological features: dispersed or loosely aggregated, monomorphic or polymorphous small or medium-sized cells with irregular shape nuclei with evident or inconspicuous nucleoli. The background may be polymorphous with mature lymphocytes granulocytes and/or eosinophils.

PTL shows a wide spectrum of cytological features: dispersed or loosely aggregated, monomorphic or polymorphous small or medium-sized cells with irregular shape nuclei with evident or inconspicuous nucleoli. The background may be polymorphous with mature lymphocytes granulocytes and/or eosinophils.

PTL shows a wide spectrum of cytological features: dispersed or loosely aggregated, monomorphic or polymorphous small or medium-sized cells with irregular shape nuclei with evident or inconspicuous nucleoli. The background may be polymorphous with mature lymphocytes granulocytes and/or eosinophils.

PTL shows a wide spectrum of cytological features: dispersed or loosely aggregated, monomorphic or polymorphous small or medium-sized cells with irregular shape nuclei with evident or inconspicuous nucleoli. The background may be polymorphous with mature lymphocytes granulocytes and/or eosinophils.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and small nucleoli. FC: CD19-, CD10-, ICC shows CD20 negativity with few scattered positive cells and diffuse positivity for CD45Ro.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and small nucleoli. FC: CD19-, CD10-, ICC shows CD20 negativity with few scattered positive cells and diffuse positivity for CD45Ro.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and small nucleoli. FC: CD19-, CD10-, ICC shows CD20 negativity with few scattered positive cells and diffuse positivity for CD45Ro.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and small nucleoli. FC: CD19-, CD10-, ICC shows CD20 negativity with few scattered positive cells and diffuse positivity for CD45Ro.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and scattered small lymphocytes in the background. FC: CD19-, CD5+, CD10-, CD4+, CD8-, CD2+, CD2/3+ CD7-. Loss of CD7 expression is frequently observed in PTL.

PTL shows polymorphous medium-sized cells with irregular shaped nuclei and scattered small lymphocytes in the background. FC: CD19-, CD5+, CD10-, CD4+, CD8-, CD2+, CD2/3+ CD7-. Loss of CD7 expression is frequently observed in PTL.

PTL shows medium-sized cells poorly differentiated lymphoid cells with irregular shaped nuclei and small nucleoli. ICC shows diffuse positivity for CD45Ro. FC: CD19-, CD5+, CD2+,CD7-.

PTL shows medium-sized cells poorly differentiated lymphoid cells with irregular shaped nuclei and small nucleoli. ICC shows diffuse positivity for CD45Ro. FC: CD19-, CD5+, CD2+,CD7-.

PTL shows medium-sized cells poorly differentiated lymphoid cells with irregular shaped nuclei and small nucleoli. ICC shows diffuse positivity for CD45Ro. FC: CD19-, CD5+, CD2+,CD7-.

Precursor T-lymphoblastic lymphoma/leukemia (TLL)

Incidence: <1% of all the NHL.
Cytology: dispersed and polymprphous medium-sized undifferentiated cells. Nuclei are round or convoluted with dispersed chromathin and small nucleoli. High mitotic index and nuclear fragility.
ICC: CD20-, CD3+, CD10-, TDT+, Ki67+ in a high percentage of the cells.
FC: CD5 +/-, CD19-, CD10-, CD2+ CD3+ CD7-.
Differential diagnosis: BL.

Dispersed and polymprphous medium-sized poorly differentiated cells. Nuclei are irregular with with clumped chromathin and small nucleoli. Numerpous mitosesmay be seen.

Dispersed and polymprphous medium-sized poorly differentiated cells. Nuclei are irregular with with clumped chromathin and small nucleoli. Numerpous mitosesmay be seen.

TLL: diffuse CD3+

NK-cell lymphoma/leukemia

Incidence: <1% of all the NHL.
Cytology: dispersed and monomorphous small- or medium-sized undifferentiated cells. The nuclei are round or convoluted with dispersed chromatin and small nucleoli. There is also a high mitotic index and nuclear fragility.
ICC: CD20-, CD3+, CD10-, TDT+, CD56+ Ki67+ in a high percentage of the cells.
FC: CD56+, CD5 -, CD19-, CD10-, CD2-CD3- CD7-.
Differential diagnosis: PTL, LLA, TLL.

NK lymphoma: dispersed and monomorphous small and poorly differentiated cells. The nuclei are oval or convoluted with dense chromatin and small nucleoli.

NK lymphoma: dispersed and monomorphous small and poorly differentiated cells. The nuclei are oval or convoluted with dense chromatin and small nucleoli.

Blastic NK-cell lymphoma/leukemia

Blastic NK lymphoma: dispersed and monomorphous medium-size and poorly differentiated or undifferentiated cells. The nuclei are irregular and fragile with dense chromatin and small nucleoli. Nuclear crushes and atypical mitoses are present. FC is mute except for CD56+

Blastic NK lymphoma: dispersed and monomorphous medium-size and poorly differentiated or undifferentiated cells. The nuclei are irregular and fragile with dense chromatin and small nucleoli. Nuclear crushes and atypical mitoses are present. FC is mute except for CD56+

Blastic NK lymphoma: dispersed and monomorphous medium-size and poorly differentiated or undifferentiated cells. The nuclei are irregular and fragile with dense chromatin and small nucleoli. Nuclear crushes and atypical mitoses are present. FC is mute except for CD56+

Blastic NK lymphoma: dispersed and monomorphous medium-size and poorly differentiated or undifferentiated cells. The nuclei are irregular and fragile with dense chromatin and small nucleoli. Nuclear crushes and atypical mitoses are present. FC is mute except for CD56+