32. T/NK cell lymphomas

T/NK lymphomas?

Lymphomas originating from T-cells (in most cases) and from NK-cells (only a few)

- rare type of non-Hodgkin lymphoma

T/NK lymphomas - how many % of non-Hodgkin lymphoma?

10-20%

Subtypes of T/NK lymphomas?

- Precursor T-cell lymphoma

- Cutaneous T-cell lymphoma

- Nodal T-cell lymphomas

- Extranodal T-cell lymphomas

- Leukaemic T-cell lymphomas

Precursor lymphomas?

There are two types of precursor lymphomas = acute lymphoblastic leukaemia

- Precursor B-cell lymphoblastic leukaemia

- Precursor T-cell lymphoblastic leukaemia

Acute lymphoblastic leukaemia translocation?

- t(9;22) translocation - BCR->ABL = Philadelphia chromosome

= signifies worse prognosis

- t(12;21) translocation

= signifies better prognosis

T-ALL translocation?

Translocation of the TCR (gene for the T-cell receptor) are involved in T-ALL

Clinical features of T-cell lymphoblastic leukaemia?

All types of acute leukaemia (B-ALL, T-ALL, AML) have similar clinical feature;

- Anaemia

- Thrombocytopaenia

- Bone pain

- Lymphadenomegaly, splenomegaly

Acute lymphoblastic leukaemia - who?

ALL is the most frequent cause of leukaemia in children

- incidence peaks at 4 years old

B-ALL develops where?

Bone marrow

- manifest as a leukaemia

Cutaneous T cell lymphoma?

- Mycosis fungoides

- Sézary syndrome

T-ALL develops where?

Thymus

- manifest as a mediastinal lymphoma, which rapidly progresses into a leukaemia

= similar to B-ALL, just with a mediastinal mass

What is mycosis fungoides?

Chronic, indolent, epidermotropic CD4+ cell lymphoma

- occur in the epidermis

Mycosis fungoides - gross and histological morphology?

- Non-specific rash, which later develops into a plaque and later a mushroom-shaped tumor

- Sézary cells infiltrate the epidermis

What is Sézary syndrome?

Advanced stage of mycosis fungoides

- cancer has spread to the lymph nodes, and sézary cells can be seen in the peripheral blood

Nodal T-cell lymphomas?

- Peripheral T-cell lymphoma not otherwise specified

- Anaplastic large cell lymphoma

- Angioimmunoblastic T-cell lymphoma

Peripheral T-cell lymphoma not otherwise specified?

Most nodal T-cell lymphomas are unclassifiable

- if a nodal T-cell lymphoma doesnt belong to the other subgroups, its considered a "not otherwise specified"

Anaplastic large cell lymphoma?

Very bad prognosis, since the cells are anaplastic

- commonly involves a mutation of the ALK gene

Angioimmunoblastic T-cell lymphoma?

One of the most common T-cell lymphomas

- derives from follicular CD4+ T-cells

Extranodal T-cell lymphomas?

- Extranodal NK/T cell lymphoma, nasal type

- Enteropathy associated T-cell lymphoma

- Hepatosplenic T-cell lymphoma

Extranodal NK/T cell lymphoma, nasal type?

Most commonly arise in the nose

- develop from NK cells (most common) or T-cells

- associated with EBV

Enteropathy associated T-cell lymphoma?

Associated with Celiac disease

Hepatosplenic T-cell lymphoma?

Originates from the γδ T-cells and not the normal αβ T-cells

- commonly affects the liver and spleen = hepatosplenomegaly

Leukaemic T-cell lymphomas?

- Adult T-cell leukaemia

- Large granular lymphocyte leukaemia

Adult T-cell leukaemia?

Highly aggressive cancer

- caused by infection of HTLV-1

Endemic in the Caribbean and southern Japan

Large granular lymphocyte leukaemia?

Chronic, indolent neoplasm

- characterized by the presence of large granular lymphocytes in the blood