Page 80 - The lraternational Journal of the Royal Society of Thailand.indd

The International Journal of the Royal Society of Thailand
Volume XV-2023

How to diagnose lymphoma

The following are the reflections on how to diagnose lymphoma.

1) Clinical information is very important to distinguish reactive states of the lymph
node from lymphoma. It is well documented that some drug reactions can produce
lymph node changes mimicking lymphoma. Pathologists should know about any
clinical history of drug administration causing lymphoproliferative disorders (LPD),

especially immunosuppressive drugs. Careful clinical history taking about
immunodeficiency states from any causes is also important. (Ngamdamrongkiat
et al, 2022; Sukpanichnant, 2022). Spectrum of tissue changes in drug reaction and

immunodeficiency states varies from lymphoid hyperplasia of any types,
polymorphic LPD, EBV mucocutaneous ulcer, and frank lymphoma seen in the
immunocompetent patients (WHO Classification of Tumours Editorial Board, 2022).
The importance of recognizing immunodeficiency states or immune dysregulation
is that all the tissue changes described above, even frank lymphoma, may regress

by reduction or discontinuation of immunosuppressive drugs (Swerdlow et al, 1993;
Ngamdamrongkiat et al, 2022; Sukpanichnant, 2022; WHO Classification of Tumours
Editorial Board, 2022).

2) Pathologists should recognize various kinds of tissue reaction in the lymph node
and extranodal tissue in order to distinguish them from lymphoma (Swerdlow et
al, 1993; Tzankov & Dirnhofer, 2018; Sukpanichnant, 2022). The most common

approach is pattern of lymph node changes depending on the compartment of lymph
node affected (pattern-based approach) (Tzankov & Dirnhofer, 2018). The other

common approach is reactive state- or lymphoproliferation-based as listed in the
beta version of the WHO-HAEM5 as tumor-like lesions with B-cell or T-cell
predominance; the former includes IgG4-related disease and Castleman disease

(unicentric, idiopathic multicentric, or KSHV/HHV8-associated multicentric) while
the latter includes Kikuchi-Fujimoto disease and Autoimmune lymphoproliferative
syndrome (WHO Classification of Tumours Editorial Board, 2022). In fact, pathologists
should recognize not only those listed in the WHO-HAEM5 but also others diseases/
reactive states such as infectious mononucleosis, HIV-related lymphadenopathy,

syphilitic lymphadenitis, drug-induced lymphadenopathy, immune deficiency/
dysregulation LPD (the so-called iatrogenic-associated LPD), immunoblastic
lymphadenopathy (polyclonal immunoblastic proliferation), progressive

transformation of germinal centers, lymphadenopathy in autoimmune diseases
(rheumatoid arthritis or systemic lupus erythematosus), and inflammatory
pseudotumor of the lymph node (Swerdlow et al, 1993; Tzankov & Dirnhofer, 2018;
Sukpanichnant, 2022).

72 Reflections on How to Diagnose and Classify Lymphoma