B-cell lymphomas may grow in
either a follicular or diffuse pattern Follicular lymphomas have well-developed
follicular structures that are similar to germinal centres.
lymphomas, cells are arranged in monotonous sheets, with no attempt at follicle
T-cell lymphomas and
lymphomas of small lymphocytic cells do not form follicles, as this is not part
of their normal repertoire.
In follicular lymphomas, neoplastic cells form
In diffuse lymphomas, neoplastic cells form diffuse sheets with no organization into follicles.
Lymphoplasmacytoid lymphoma B-cell lymphoblastic lymphomas are high-grade
B-cell lymphomas range from
small-cell tumours to immunoblastic types B-cell lymphomas range in morphology
from small-cell tumours, through cells resembling centrocytes and centroblasts,
Generally speaking, centroblastic and immunoblastic tumours behave in a more aggressive fashion than
small lymphocytic and centrocytic lymphomas. B-cell lymphocytic (small cell)
lymphoma is seen in elderly patients.
B-cell (small cell)
lymphocytic lymphomas are low-grade tumours composed of cells that cytologically
resemble small lymphocytes; there is an overlap with chronic lymphocytic
leukaemia, which is composed of virtually identical cells.
The disease occurs in the
elderly, typically running an indolent course over many years. It can present
with enlarged nodes or anaemia secondary to infiltration of bone marrow (seen in
Immune deficiency secondary
to hypogammaglobulinaemia is seen in many patients, frequently leading to death
by predisposing to infection. The 5-year survival is better than 60% with this
It is common for overspill
of cells into the bloodstream to give a picture similar to chronic lymphocytic
Lymphomas formed from follicle centre cells (both centrocytes and
centroblasts are the most common type of non-Hodgkin's lymphoma, accounting for
about 40% of cases. In the vast majority of cases, cells arrange themselves into
follicles to form a follicular pattern of lymphoma. In other cases a mixed
follicular and diffuse pattern is seen. Follicular lymphoma occurs most commonly
after the sixth decade.
It is usually extensive at
presentation, with involvement of bone marrow and liver. Although an indolent
disease with slow progression over many years, it is difficult to cure, even
with aggressive chemotherapy.
Median survival is about 10
years. As part of the natural history of this disease, many cases transform into
a high-grade diffuse lymphoma. Follicular lymphomas frequently show a
chromosomal translocation that activates the oncogene. Diffuse lymphoma formed
from small follicle centre cells is uncommon, but may pursue an aggressive
Lymphomas derived from large
follicle centre cells (centroblastic cells). They are classed as the
intermediate grade in the working formulation, but are high-grade tumours in the
Histologically, nodes are
replaced by sheets of large atypical lymphoid cells.
Because this type of
lymphoma grows so fast, enlargement of nodes is very obvious and patients notice
the signs early.
As a result, disease is
often localized at the time of diagnosis. Presentation with extranodal disease
is common, for example, with gut involvement.
This type of lymphoma affects all
ages, including children, but is most common in later adult life.
It may develop
from progression of follicular lymphoma (secondary centroblastic/large cell
Even when advanced, the
disease is curable with aggressive chemotherapy. Immunoblasts are large cells
with prominent central nucleoli.
Immunoblastic lymphomas of B-cell type are most
common in the elderly, but may be seen at any age. They are a form of high-grade
lymphoma, presenting with rapid enlargement of nodes; consequently, patients are
diagnosed at an early stage. Disease may also develop by transformation of
low-grade B-cell lymphomas.
lymphomas are high-grade tumours mainly seen in childhood Lymphoblastic
lymphomas are composed of cells resembling transformed lymphocytes. There is
great overlap with B-cell acute lymphoblastic leukaemia.
There is extensive
nvolvement of nodes and extranodal sites, dictating the use of aggressive
therapy (including irradiation of the neuraxis). Burkitt's lymphoma is a type of
lymphoblastic lymphoma that is endemic in Africa, but arises sporadically
elsewhere, particularly affecting the jaw, ovaries, and gut.
In endemic Burkitt's
lymphoma, Epstein-Barr virus genome is found in over 90% of cases, contrasting
with under 20% of cases in sporadic disease. Translocation of chromosome 8 to
chromosome 14, resulting in activation of the c-myc oncogene, is seen in 80% of
A characteristic feature is
the presence of large macrophagic cells scattered through the tumour, likened to
a 'starry sky'.