Pediatric Infradiaphragmatic Hodgkin’s lymphoma: a unique identity

Abstract

Background: Infra-diaphragmatic Hodgkin’s lymphoma (IDHL) is a rare disease. The prognostic impact of infra-diaphragmatic localization of this lymphoma is controversial. We aim to evaluate the clinic-pathologic features and outcome of IDHL. Methods: Between 2007 and 2020, all patients with histologically confirmed stage I/II IDHL were retrospectively evaluated including clinical presentation, initial lab work, radiological findings, response to initial treatment and their outcome in comparison to stage I/II supra-diaphragmatic HL (SDHL). Results: Among 991 Hodgkin’s lymphoma (HL) staged I/II, there were 35 IDHL (3.5%) patients with male to female ratio 2.5:1, median age of 10.1 years, 34.3% (12/35) of cases were histologically nodular lymphocytic predominant HL (NLPHL) while 37.1% (13/35) were classical HL (CHL) of mixed cellularity (MC) type, 34.3% (12/35) of patients presented with B symptoms. In 57% of cases erythrocyte sedimentation rate (ESR) was less than 30, 20% (7/35) of patients relapsed. Overall survival (OS) was 87.8% while relapse free survival (RFS) was 76.2% at 5 years, OS and RFS of the patients with adequate interim positron emission tomography/computed tomography (PET/CT) response were higher than those with inadequate response at 5 years (P<0.001). OS according to diaphragmatic site was statistically significant (P=0.016) (88.1% for infra, vs. 98.2% for supra-diaphragmatic) while RFS according to diaphragmatic site was also statistically significant (P<0.001) (76.2%) for infra, versus (93%) for supra-diaphragmatic at 5 years. Conclusions: Although IDHL cases do not carry high risk features still this category of the patients has lower OS and RFS in comparison to supra-diaphragmatic cases at initial presentation making infra-diaphragmatic site by itself a bad prognostic factor.