The Pathogenesis of Indolent Cutaneous B Cell Lymphoma

Primary cutaneous B cell lymphomas (CBCL) are rare skin cancers, affecting only about four in a million people each year. Traditionally, these diseases are treated as true lymphomas requiring respective therapy. However, our previous research using advanced single-cell RNA sequencing revealed that many slow-growing (indolent) CBCL cases may not be cancers at all. Instead, they appear to be persistent immune responses, resembling the bodys reaction to long-term exposure to an unknown trigger, such as an antigen. Even more concerning, when we asked three leading European medical centers to diagnose the same samples blindly, their assessments often disagreed. This inconsistency can lead to misdiagnoses and unnecessary, potentially harmful treatments for patients. Our study challenges the long-held belief that all CBCL cases are malignant. We propose that many indolent CBCL cases are not true lymphomas but rather chronic immune reactions. To test this, we aim to identify the specific antigen driving these reactions and develop reliable clinical tests to distinguish between harmless immune responses and genuine cancers. Using cutting-edge techniques we will pinpoint the target antigen in indolent CBCL. Simultaneously, we will analyze extensive single-cell data to uncover biological markers that separate benign from malignant lesions. These findings will be used to create targeted diagnostic tools, such as specialized immunohistochemistry panels and machine-learning models, to improve accuracy in pathology labs. This project is a collaboration between clinicians and basic scientists at the Medical University of Vienna, led by dermatologist and bioinformatics expert Johannes Griss. By redefining how we understand and diagnose CBCL, we hope to prevent overtreatment, reduce patient anxiety, and pave the way for more precise, personalized care. Our work could transform the management of these rare diseases, offering clearer diagnoses and better outcomes for those affected.