Lymphoma & related disorders

Table 1: T / NK cell entities - comparison of WHO (2016), WHO (2022) and ICC (2022)

WHO HAEM4R	WHO HAEM5	ICC
Precursor T cell neoplasms
T lymphoblastic leukemia / lymphoma	T lymphoblastic leukemia / lymphoma, NOS	T lymphoblastic leukemia / lymphoma
Early T cell precursor lymphoblastic leukemia / lymphoma	Early T cell precursor lymphoblastic leukemia	Early T cell precursor acute lymphoblastic leukemia, NOS
		Early T cell precursor acute lymphoblastic leukemia, BCL11B activated
NK lymphoblastic leukemia / lymphoma*	[Entity removed]	NK cell acute lymphoblastic leukemia*
Tumor-like lesions with T cell predominance
[Not included]	Kikuchi-Fujimoto disease	[Not included]
[Not included]	Indolent T lymphoblastic proliferation	[Not included]
[Not included]	Autoimmune lymphoproliferative syndrome	[Not included]
Mature T / NK cell leukemias
T prolymphocytic leukemia	T prolymphocytic leukemia	T cell prolymphocytic leukemia
T cell large granular lymphocytic leukemia	T large granular lymphocytic leukemia	T cell large granular lymphocytic leukemia
Chronic lymphoproliferative disorder of NK cells*	NK large granular lymphocytic leukemia	Chronic lymphoproliferative disorder of NK cells*
Adult T cell leukemia / lymphoma	Adult T cell leukemia / lymphoma	Adult T cell leukemia / lymphoma
Sézary syndrome	Sézary syndrome	Sézary syndrome
Aggressive NK cell leukemia	Aggressive NK cell leukemia	Aggressive NK cell leukemia
Primary cutaneous T cell lymphomas
Primary cutaneous CD4 positive small or medium T cell LPD*	Primary cutaneous CD4 positive small or medium T cell LPD	Primary cutaneous small or medium CD4 positive T cell LPD
Primary cutaneous acral CD8 positive T cell lymphoma*	Primary cutaneous acral CD8 positive lymphoproliferative disorder	Primary cutaneous acral CD8 positive lymphoproliferative disorder
Mycosis fungoides	Mycosis fungoides	Mycosis fungoides
Primary cutaneous CD30 positive T cell LPD: lymphomatoid papulosis	Primary cutaneous CD30 positive T cell LPD: lymphomatoid papulosis	Primary cutaneous CD30 positive T cell LPD: lymphomatoid papulosis
Primary cutaneous CD30 positive T cell LPD: primary cutaneous anaplastic large cell lymphoma	Primary cutaneous CD30 positive T cell LPD: primary cutaneous anaplastic large cell lymphoma	Primary cutaneous CD30 positive T cell LPD: primary cutaneous anaplastic large cell lymphoma
Subcutaneous panniculitis-like T cell lymphoma	Subcutaneous panniculitis-like T cell lymphoma	Subcutaneous panniculitis-like T cell lymphoma
Primary cutaneous gamma / delta T cell lymphoma	Primary cutaneous gamma / delta T cell lymphoma	Primary cutaneous gamma / delta T cell lymphoma
Primary cutaneous CD8 positive aggressive epidermotropic cytotoxic T cell lymphoma*	Primary cutaneous CD8 positive aggressive epidermotropic cytotoxic T cell lymphoma	Primary cutaneous CD8 positive aggressive epidermotropic cytotoxic T cell lymphoma
[Not included]	Primary cutaneous peripheral T cell lymphoma, NOS	[Not included]
Intestinal T cell and NK cell lymphoid proliferations and lymphomas
Indolent T cell lymphoproliferative disorder of the gastrointestinal tract*	Indolent T cell lymphoma of the gastrointestinal tract	Indolent clonal T cell LPD of the gastrointestinal tract
[Not included]	Indolent NK cell LPD of the gastrointestinal tract	Indolent NK cell LPD of the gastrointestinal tract
Enteropathy associated T cell lymphoma	Enteropathy associated T cell lymphoma	Enteropathy associated T cell lymphoma
		Type II refractory celiac disease
Monomorphic epitheliotropic intestinal T cell lymphoma	Monomorphic epitheliotropic intestinal T cell lymphoma	Monomorphic epitheliotropic intestinal T cell lymphoma
Intestinal T cell lymphoma, NOS	Intestinal T cell lymphoma, NOS	Intestinal T cell lymphoma, NOS
Hepatosplenic T cell lymphoma
Hepatosplenic T cell lymphoma	Hepatosplenic T cell lymphoma	Hepatosplenic T cell lymphoma
Anaplastic large cell lymphoma
Anaplastic large cell lymphoma, ALK positive	ALK positive anaplastic large cell lymphoma	Anaplastic large cell lymphoma, ALK positive
Anaplastic large cell lymphoma, ALK negative	ALK negative anaplastic large cell lymphoma	Anaplastic large cell lymphoma, ALK negative
Breast implant associated anaplastic large cell lymphoma*	Breast implant associated anaplastic large cell lymphoma	Breast implant associated anaplastic large cell lymphoma
Nodal T follicular helper (TFH) cell lymphoma
Angioimmunoblastic T cell lymphoma	Nodal TFH cell lymphoma, angioimmunoblastic type	Follicular helper T cell lymphoma, angioimmunoblastic type
Follicular T cell lymphoma*	Nodal TFH cell lymphoma, follicular type	Follicular helper T cell lymphoma, follicular type
Nodal peripheral T cell lymphoma (PTCL) with TFH phenotype*	Nodal TFH cell lymphoma, NOS	Follicular helper T cell lymphoma, NOS
Other peripheral T cell lymphomas
Peripheral T cell lymphoma, NOS	Peripheral T cell lymphoma, NOS	Peripheral T cell lymphoma, NOS
EBV positive NK / T cell lymphomas
[Not included] [variant of PTCL, NOS]	EBV positive nodal T and NK cell lymphoma	Primary nodal Epstein-Barr virus positive T / NK cell lymphoma*
Extranodal NK / T cell lymphoma, nasal type	Extranodal NK / T cell lymphoma	Extranodal NK / T cell lymphoma, nasal type
EBV positive T and NK cell lymphoid proliferations and lymphomas of childhood
Severe mosquito bite allergy	Severe mosquito bite allergy	Severe mosquito bite allergy
Hydroa vacciniforme-like lymphoproliferative disorder	Hydroa vacciniforme lymphoproliferative disorder, classic or systemic	Hydroa vacciniforme lymphoproliferative disorder, classic or systemic
Chronic active EBV infection of T and NK cell type, systemic form	Systemic chronic active EBV disease	Chronic active EBV disease (T and NK cell phenotype)
Systemic EBV positive T cell lymphoma of childhood	Systemic EBV positive T cell lymphoma of childhood	Systemic EBV positive T cell lymphoma of childhood

Note: asterisk (*) denotes a provisional entity

Contributed by Tom Deng, M.D.

Which of the following conditions is categorized by the WHO 5th edition (2022) as a tumor-like condition with T cell predominance?

1. Castleman disease
2. Cold agglutinin disease
3. Erdheim-Chester disease
4. Kikuchi-Fujimoto disease

D. Kikuchi-Fujimoto disease is considered as a tumor-like condition with T cell predominance, which is a newly defined category in the WHO 5th edition (2022). Answers C and B are incorrect because Erdheim-Chester disease is a histiocytic lesion while cold agglutinin disease is predominated by plasma cells. Answer A is incorrect because Castleman disease is a proliferation of mostly B cells or plasma cells.

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Reference: WHO 2022 & ICC-T / NK cell

Which of the following conditions is newly recognized by the WHO 5th edition (2022) and International Consensus Classification as neoplastic?

1. Indolent NK cell lymphoproliferative disorder of the gastrointestinal tract
2. Indolent T lymphoblastic proliferation
3. NK lymphoblastic leukemia / lymphoma
4. Primary cutaneous acral CD8 positive lymphoproliferative disorder

A. Indolent NK cell lymphoproliferative disorder of the gastrointestinal tract, previously thought to be reactive, is newly recognized as neoplastic. Answer B is incorrect because indolent T lymphoblastic proliferation is not considered neoplastic under WHO 5th edition (2022) but a tumor-like lesion with T cell predominance. Answer C is incorrect because NK lymphoblastic leukemia / lymphoma, a provisional entity under the WHO 4th revised edition, is no longer considered a distinct entity. Answer D is incorrect because primary cutaneous acral CD8 positive lymphoproliferative disorder has been downgraded from lymphoma due to its indolent clinical course.

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Reference: WHO 2022 & ICC-T / NK cell