Is Kaposi sarcoma a novel comorbidity of cutaneous lymphoma? A systematic review of the literature.

Background and Objectives: Patients with cutaneous lymphomas (CL) are at an increased risk of developing secondary malignancies. This study aimed to assess the frequency of association between CL and Kaposi sarcoma (KS) and to identify factors that may promote the co-occurrence of these two diseases.
Patients and Methods: On January 25, 2024, we conducted a systematic search of four electronic medical databases to identify all published cases of KS associated with CL. The clinical course and outcomes of these patients were summarized. For critical appraisal, we applied the JBI Checklist for Case Reports. The study was registered in the PROSPERO database (CRD42022313204).
Results: A total of 40 articles reporting on 45 patients were assessed for eligibility. We included 27 cases in the final analysis (26 cutaneous T-cell lymphomas, 1 cutaneous B-cell lymphoma). In 71% of cases, the diagnosis of CL preceded KS. Nearly half (48%) of the patients had erythrodermic mycosis fungoides or Sézary syndrome. KS lesions were predominantly limited to the skin, with complete remission achieved in 53% of cases.
Conclusions: The association between KS and CL is rare, limiting our study due to the small sample size and potential reporting bias. Skin-targeted therapies, a restricted T-cell repertoire, and impaired T-cell responses in erythrodermic CTCL patients may contribute to the development of KS.
(© 2025 The Author(s). Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)