Page 396 - Textbook of Pathology, 6th Edition

380 lymphotropic virus-I (HTLV-I) (Chapter 8). The infection is too. This staging system depends upon the number and
acquired by blood transfusion, breast milk, sexual route or location of nodal and extranodal sites involved, and presence
transplacentally. ATLL is common in Japan, the Caribbean or absence of constitutional (B) symptoms. But the concept
and parts of the US but is rare in rest of the world. of staging is much less helpful in NHL than in Hodgkin’s
disease because the prognosis is not correlated with the
MORPHOLOGICAL FEATURES. The involved lymph anatomic site of involvement of the disease.
nodes have proliferation of CD4 positive large atypical T-
cells with indented nuclei, called ‘flower cells’, most PLASMA CELL DISORDERS
prominent in the paracortical zone. The blood also shows
large pleomorphic T-cell leukaemia. The plasma cell disorders are characterised by abnormal
proliferation of immunoglobulin-producing cells and result
The patients have usually widespread lymphadenopathy in accumulation of monoclonal immunoglobulin in serum
with leukaemia, hepatosplenomegaly and involvement of and urine. The group as a whole is known by various
skin and leptomeninges. This disease runs a fulminant synonyms such as plasma cell dyscrasias, paraproteinaemias,
course. dysproteinaemias and monoclonal gammopathies. The group
comprises the following six disease entities:
ANAPLASTIC LARGE T/NK CELL LYMPHOMA
1. Multiple myeloma
This relatively newer entity is the T-cell counterpart of diffuse 2. Localised plasmacytoma
large B-cell lymphoma and was previously included under 3. Lymphoplasmacytic lymphoma (discussed above)
SECTION II
malignant histiocytosis or diagnosed as anaplastic carcinoma. 3. Waldenström’s macroglobulinaemia
MORPHOLOGICAL FEATURES. There is diffuse 4. Heavy chain disease
infiltration of lymph nodes by anaplastic T-cells/null cells 5. Primary amyloidosis (Chapter 4)
positive for CD30 (Ki-1). Cytogenetic abnormality consists 6. Monoclonal gammopathy of undetermined significance
of t(2;5). Involvement of the skin occurs frequently and (MGUS).
produces an indolent cutaneous large T/null cell The feature common to all plasma cell disorders is the
lymphoma. neoplastic proliferation of cells derived from B-lymphocyte
lineage. These disorders constitute 16% of all B-cell
PERIPHERAL T-CELL LYMPHOMAS malignancies. Normally B lymphocytes have surface
immunoglobulin molecules of both M and G heavy chains.
This group includes a variety of aggressive T-cell lymphomas
which are morphologically heterogeneous but have common Under normal circumstances, B-cells are stimulated by
immunotypic features of mature T-cells (CD4+, CD8+, or exposure to surface immunoglobulin-specific antigen and
both). These are more common in young adults and often mature to form IgG-producing plasma cells. However, in
have bone marrow involvement at presentation. Subtypes plasma cell disorders, the control over this process is lost
of peripheral T-cell lymphomas include the following and results in abnormal production of immunoglobulin that
syndromes: appears in the blood and urine. These disorders differ from
i) Angioimmunoblastic T-cell lymphoma is relatively more other B-cell lymphoid malignancies in having monoclonal
common subtype, comprising about 20% of all T-cell NHLs. synthesis of immunoglobulins and lack of prominent lymph-
The patients have profound constitutional symptoms (fever, adenopathy. In addition to the rise in complete immuno-
weight loss, skin rash), generalised lymphadenopathy and globulins, plasma cell disorders synthesise excess of light
polyclonal hypergammaglobulinaemia. chains (kappa or lambda), or heavy chains of a single class
Haematology and Lymphoreticular Tissues
ii) Extranodal T/NK cell lymphoma of nasal type is involvement (alpha, gamma, or mu). Bence Jones proteins are free light
of the upper airways by the monoclonal T-cells. The condition chains present in blood and excreted in urine of some plasma
is quite aggressive and was earlier called as lethal midline cell disorders.
granuloma or angiocentric lymphoma. The patients have After these brief general comments, we now turn to the
haemophagocytic syndrome. During the course of the discussion of the specific plasma cell disorders.
disease, blood and bone marrow may be involved producing
leukaemic picture. MULTIPLE MYELOMA
iii) Enteropathy type T-cell lymphoma is a rare aggressive Multiple myeloma is a multifocal malignant proliferation of
lymphoma seen in association with untreated cases of gluten- plasma cells derived from a single clone of cells (i.e.
sensitive enteropathy. monoclonal). The terms multiple myeloma is used
iv) Hepatosplenic T-cell lymphoma, unlike other lymphomas interchangeably with myeloma. The tumour, its products (M
which occur as tumour masses, is characterised by sinusoidal component), and the host response result in the most
infiltration of the liver, spleen and bone marrow by important and most common syndrome in the group of
monoclonal T-cells. Systemic features are often present. plasma cell disorders that produces osseous as well as
extraosseous manifestations. Multiple myeloma primarily
Staging of NHL
affects the elderly (peak incidence in 5th-6th decades) and
The Ann Arbor staging system developed for Hodgkin’s increases in incidence with age. It is rare under the age of 40.
disease (see Table 14.10, page 372) is used for staging NHL Myeloma is more common in males than females.