Page 393 - Textbook of Pathology, 6th Edition

true complete remission. Treatment is, therefore, palliative large B-cell lymphoma. Median survival for patients with 377
and symptomatic, and with optimal management patient can low grade follicular lymphoma is 7-9 years.
usually lead a relatively normal life for several years. These
approaches include: alkylating drugs (e.g. chlorambucil, Diffuse Large B-cell Lymphoma
cyclophosphamide), corticosteroids and radiotherapy. Diffuse large B-cell lymphoma, earlier termed as diffuse
Splenectomy is indicated in cases of CLL with autoimmune poorly-differentiated lymphocytic lymphoma or follicular
haemolytic anaemia. centre cell diffuse large, cleaved/non-cleaved lymphoma, is
Prognosis of CLL/SLL is generally better than CML since the most common comprising about 31% of all NHLs. It
blastic transformation seldom occurs. Prognosis generally occurs in older patients with mean age of 60 years. It may
correlates with the stage of disease as under: present primarily as a lymph node disease or at extranodal
Stage A: characterised by lymphocytosis alone, or with limited sites. About half the cases have extranodal involvement at
lymphadenopathy, has a good prognosis (median survival the time of presentation, particularly in the bone marrow
more than 10 years). and the alimentary tract. Primary diffuse large B-cell
Stage B: having lymphocytosis with associated significant lymphoma of CNS may also occur.
lymphadenopathy and hepatosplenomegaly has A few subtypes of diffuse large B-cell lymphoma are
intermediate prognosis (median survival about 5 years). described with distinct clinicopathologic settings: CHAPTER 14
Epstein-Barr virus (EBV) infection has been etiologically
Stage C: having lymphocytosis with associated anaemia and implicated in diffuse large B-cell lymphoma in immuno-
thrombocytopenia has a worse prognosis (median survival suppressed patients of AIDS and organ transplant cases.
of less than 2 years). Human herpes virus type 8 (HHV-8) infection along with
Generally, the course is indolent. However, some cases of presence of immunosuppression is associated with a subtype
SLL may transform into more aggressive diffuse large B-cell of diffuse large B-cell lymphoma presenting with effusion,
lymphoma, or may be associated with occurrence of an IgM termed primary effusion lymphoma.
monoclonal gammopathy called Waldenström’s macro- Mediastinal large B-cell lymphoma is diagnosed in patients
globulinaemia (page 384). with prominent involvement of mediastinum, occurs in
young females and frequently spreads to CNS and abdominal
FOLLICULAR LYMPHOMA viscera.
In the earlier classification schemes, follicular lymphoma was MORPHOLOGIC FEATURES. This variety is the diffuse
known as nodular (poorly-differentiated) or follicular counterpart of follicular large cleaved cell lymphoma i.e.
lymphoma (predominantly small/large cleaved cell type). it is composed of large cleaved cells spread in a diffuse
Follicular lymphomas comprise approximately 22% of all pattern. The cytoplasm in these tumour cells is pale and
NHLs. Follicular lymphomas occur in older individuals, abundant while the nuclei have prominent 1-2 nucleoli.
most frequently presenting with painless peripheral Immunophenotypic markers for pan-B cells (CD19, CD20) Disorders of Leucocytes and Lymphoreticular Tissues
lymphadenopathy which is usually waxing and waning type. are positive, besides overexpression of surface immuno-
In contrast to diffuse lymphomas, extranodal involvement globulins (IgM, IgG and light chains) and of BCL-2 protein.
is also infrequent.
In general, diffuse large B-cell lymphomas are aggressive
MORPHOLOGIC FEATURES. Following features are tumours and disseminate widely.
seen:
Lymph node biopsy: As the name suggests, follicular BURKITT’S LYMPHOMA/LEUKAEMIA
lymphoma is characterised by follicular or nodular pattern Burkitt’s lymphoma/leukaemia is an uncommon tumour in
of growth. The nuclei of tumour cells may vary from adults but comprises about 30% of childhood NHLs. Burkitt’s
predominantly small cleaved (or indented) to leukaemia corresponds to L3 ALL of FAB grouping and is
predominantly large cleaved variety (Fig. 14.21,C). The uncommon. Three subgroups of Burkitt’s lymphoma are
former is more common, has infrequent mitoses and the recognised: African endemic, sporadic and immunodeficiency-
rate of growth slow (low grade), while the patients with associated.:
large cell lymphoma have high proliferation and progress African endemic Burkitt’s lymphoma was first described
rapidly (high grade). In all follicular lymphomas, the in African children, predominantly presenting as jaw tumour
tumour cells are positive for pan-B markers such as CD19 that spreads to extranodal sites such as the bone marrow
and CD20 along with expression of BCL-2 protein (for and meninges. The relationship of this tumour with
distinction from normal germinal centre which is BCL-2 oncogenic virus, Epstein-Barr virus (EBV), has been discussed
negative). Cytogenetic studies show characteristic trans- in Chapter 8.
location t(14;18) in tumour cells. Sporadic Burkitt’s lymphoma is a related tumour in which
Blood and bone marrow: Peripheral blood involvement the tumour cells are similar to those of Burkitt’s lymphoma
as occurs in SLL is uncommon in this variety. Infiltration but are more pleomorphic and may sometimes be multi-
in the bone marrow is typically paratrabecular. nucleated. Sporadic variety has a propensity to infiltrate the
CNS and is more aggressive than true Burkitt’s lymphoma.
About half the cases of low-grade follicular lymphomas, Immunodeficiency-associated Burkitt’s lymphoma includes
during their indolent biologic course, may evolve into diffuse cases seen in association with HIV infection.