Transformation of Classical Hodgkin Lymphoma Into Non-Hodgkin Lymphoma: Three Case Reports From the West Bank.

Background: Classical Hodgkin lymphoma (cHL) is a highly curable B-cell malignancy; though, rarely, it can transform into non-Hodgkin lymphoma (NHL), including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, or marginal zone lymphoma. Reports of such transformations remain limited in the literature. Objective: The aim of this study is to describe the clinical course, histopathological findings, and outcomes of three patients with cHL who developed secondary NHL. Results: Case 1 involved transformation from cHL to CD20+/CD30+ DLBCL following multiple lines of chemotherapy and autologous stem cell transplant, eventually resulting in progressive disease and death. Case 2 transformed into follicular lymphoma Grade 3a more than a year after cHL remission, with marrow infiltration managed conservatively pending systemic therapy. Case 3 presented with composite lymphoma at diagnosis (cHL and extranodal marginal zone lymphoma) and experienced indolent but recurrent disease involving the liver, requiring multiple rounds of chemoimmunotherapy. Conclusion: Transformation of cHL into NHL, though rare, may occur years after initial treatment or concurrently at presentation. These cases underscore the importance of repeat biopsy in suspected relapses and highlight the clinical and pathological heterogeneity of such transformations. Our paper adds to the limited literature on this phenomenon and is the first of its kind reported from Palestine.