Page 77 - The lraternational Journal of the Royal Society of Thailand.indd

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

of origin in DLBCL – germinal center B-cell (GCB) or activated B-cell (ABC) – rendering
subgrouping of DLBCL in term of different treatment regimens (WHO Classification
of Tumours Editorial Board, 2022). Recently, genetic landscapes of many types of
lymphoma have been published, giving the detailed genetic information about the
typical cases of lymphomas in certain entities (WHO Classification of Tumours

Editorial Board, 2022). Certainly, all of these genetic landscapes provide us better
understanding in those entities of lymphomas, but the reflection on the molecular
genetic advances is that how many cases of the so-called “typical” or “classic” entities

of lymphomas are required – 20, 50, 100, or several hundreds – so that we can have
confidence on the information provided by these perplexing genetic landscapes.

The last reflection to give is upon the essential diagnostic criteria given in
each entity of lymphoma according to the beta version of the WHO classification of
haematolymphoid tumours, 5th edition (WHO-HAEM5). The general introduction of

the WHO-HAEM5 describes about essential and desirable diagnostic criteria for each
entity as follow:

“The essential and desirable diagnostic criteria for each entity are
intended to facilitate distilling the key diagnostic components needed
to classify a particular disease type. Essential diagnostic criteria are

considered must-have features, whereas desirable diagnostic criteria
are nice-to-have features (i.e. they support a diagnosis but are not
mandatory). The listing of essential diagnostic criteria that have the
broadest possible applicability is intended to aid in the applicability of
the classification particularly in limited resource settings where feasi-

ble. It is hoped that the genetic underpinnings of the classification will
prompt and urge the provision of local health resources to ensure that
the necessary genetic testing platforms are available to peruse the full

potential of the classification. The importance of such resources being
available locally in some regions or even countries stems from the
fact that sending out tests to remote reference labs tends to limit the
availability of accurate public health data within the local community.”
(WHO Classification of Tumours Editorial Board, 2022)

But, in daily practice in countries with limited resource settings, some of the
essential diagnostic criteria are still not accessible so that the making diagnosis of a
specific lymphoma type may have problem. For example, in plasmablastic lymphoma
(PBL), essential diagnostic criteria include 1) lymphoma with plasmablastic/
immunoblastic morphology, 2) expression of plasma cell associated antigens (e.g.

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