False Positive Infectious Serologies Mimicking Viral Exanthem in a Patient with Angioimmunoblastic T-Cell Lymphoma

Abstract

Angioimmunoblastic T-cell lymphoma (AITL) represents a severe subtype of peripheral T-cell lymphoma and mimics drug reactions, infection, or autoimmune diseases. Due to its nonspecific clinical features, diagnosing AITL can be difficult and is frequently delayed. We report a case of a 70-year-old Thai male who presented with fever and generalized morbilliform eruption. Initial laboratory investigations revealed positive serological tests for Mycoplasma, Measle virus, and Epstein-Barr virus. The patient was treated with appropriate antibiotics, however, there was no clinical improvement. The lack of response to antibiotic therapy prompted reconsideration of the initial diagnosis. Subsequent careful examination revealed enlarged cervical lymph nodes, lymph node biopsy confirmed AITL. In patient with AITL, we hypothesize that positive serological tests for multiple pathogens often result from immune dysregulation or cross-reactivity rather than true infections. Therefore, physicians must interpret these findings cautiously to avoid misdiagnosis.