Upward trend in follicular lymphoma among the Korean population: 10-year experience at a large tertiary institution

Classical Hodgkin lymphoma following follicular lymphoma: a case report

The simultaneous, composite, or sequential occurrence of follicular lymphoma (FL) and classical Hodgkin lymphoma (HL), both of which originate from germinal center B-cell, is rare. Questions have been raised with regard to the type of tests that pathologists should perform when observing the presence of a "large-cell lymphoma" following an FL and what are the most critical pathological points for diagnosis. Here, we present a case of a classical HL following an FL after administering rituximab-bendamustine (R-Benda) chemotherapy. Furthermore, we also summarized the literature and compared this case with other HLs that followed FLs. A 55-year-old woman was diagnosed with a grade 3A FL of the breast and axillary lymph node masses. She completed six R-Benda chemotherapy cycles for stage IV FL. Twenty-three months after the diagnosis, follow-up image studies showed an increase in the size and number of the lesions. Biopsies of the neck lymph node and liver were performed, and the diagnosis was classical HL. Sequential or composite FL and HL may sometimes develop from the same clone because they share the same genetic alterations, such as B-cell lymphoma (Bcl)-2 or Bcl-6 translocation. When a large-cell lymphoma is found after the treatment of FL, classical HL should be considered a pathological differential diagnosis, and histological, immunohistochemical, or molecular investigations must be considered during the diagnostic process.

Incidence Trend of Follicular Lymphoma in Taiwan Compared to Japan and Korea, 2001-2019

A continuous increase in follicular lymphoma has been observed in Taiwan, Japan, and South Korea over the last few decades. This study aimed to evaluate the difference in incidence trends of follicular lymphoma in Taiwan, Japan, and South Korea between 2001 and 2019. The data for the Taiwanese populations was obtained from the Taiwan Cancer Registry Database, and those for the Japanese and Korean population were retrieved from the Japan National Cancer Registry and some additional reports, both of which included population-based cancer registry data, from Japan and Korea. Follicular lymphoma accounted for 4231 cases from 2002-2019 in Taiwan, 3744 cases from 2001-2008 and 49,731 cases from 2014-2019 in Japan; and 1365 cases from 2001-2012 and 1244 cases from 2011-2016 in South Korea. The annual percentage change for each time period was 3.49% (95% confidence interval: 2.75-4.24%) in Taiwan, 12.66% (95% confidence interval [CI]: 9.59-15.81%) and 4.95% (95% CI: 2.14-7.84%) in Japan, and 5.72% (95% CI: 2.79-8.73%) and 7.93% (95% CI: -1.63-18.42%) in South Korea. Our study confirms that the increasing trends of follicular lymphoma incidence in Taiwan and Japan have been remarkable in recent years, especially the rapid increase in Japan between 2014 and 2019; however, there was no significant in-crease from 2011 to 2015 in South Korea.

Incidence, Clinicopathologic Features, and Genetics of in situ Follicular Neoplasia: A Comprehensive Screening Study in a Japanese Cohort

AIMS

In situ follicular neoplasia (ISFN) is a histologically recognisable neoplastic proliferation of follicular lymphoma (FL)-like B cells confined to the germinal centres. While some ISFNs are associated with overt FL, others are incidentally identified as isolated or pure forms in individuals without evidence of overt FL. The prevalence of incidentally found isolated ISFN is approximately 3% in Europe; however, no screening study has been conducted in Asia. To investigate the incidence and clinicopathologic characteristics of ISFNs in the Japanese population, we conducted histopathological screening of the lymph nodes (LNs) resected for solid tumours or inflammatory conditions.

METHODS AND RESULTS

We screened for ISFN in 5,700 LNs from 340 individuals using immunohistochemistry for BCL2 and identified seven ISFNs, with an incidence of 2.1%. The median age of the individuals with ISFN was 67 years, none of whom developed overt FL, with a median follow-up of 59 months. Next-generation sequencing was performed in five ISFNs, and ten variants in seven FL-associated genes were identified. The identified variants included HIST1H1E (2/5), ARID1A (2/5), KMT2D (1/5), CARD11 (1/5), BCL7A (1/5), CREBBP (1/5), and TNFRSF14 (1/5).

CONCLUSIONS

The incidence of isolated ISFN in the Japanese population is not significantly different from that in Europe, presumably reflecting the recent increase in FL in Japan. These incidentally found ISFNs have a low potential to transform into overt FL. Although mutations of FL-associated genes are already present in ISFNs, further molecular studies are needed to identify driver genes leading to the transformation of ISFN to overt FL.