Classical Hodgkin Lymphoma progressing to Nodal T follicular helper cell lymphomas with aberrant CD20 expression and monoclonal TCR, IG rearrangements: A case report

Abstract Background CHL is a rare malignant neoplasm of the lymphatic system. While CHL typically responds well to conventional treatments, some cases may experience relapse or progression to other subtypes, with the development of secondary PTCL being relatively uncommon. Herein, we report a rare case of nTFHL-NOS arising from CHL, accompanied by aberrant CD20 expression and clonal rearrangements of TCR and IG. Case presentation: A 74-year-old male, was diagnosed with CHL, leaning towards the mixed cell type, six years ago. He received six cycles of the ABVD regimen, achieving complete clinical remission. The patient was admitted to our hospital due to the appearance of multiple skin nodules 66 months later. Physical examination showed a palpable mass measuring 3cm × 2cm in its largest dimension on the skin of the right shoulder blade, characterized by firm consistency and limited mobility. A subcutaneous tissue biopsy of the right shoulder blade was performed. Histopathological analysis revealed nTFHL-NOS, with aberrant CD20 expression and clonal rearrangements of TCR and IG. The patient underwent two cycles of chemotherapy with brentuximab vedotin and the G-mox regimen, resulting in a reduction of the skin lesions to 2cm × 1cm. Conclusion EBV infection, complex tumor microenvironment, and genetic susceptibility may all contribute to the occurrence of CHL progressing to PTCL. Addressing the stability of the tumor microenvironment during CHL treatment to mitigate the risk of secondary PTCL development poses a significant challenge that warrants investigation.