Cutaneous Granulomas Associated With Rubella Replication in TAP Deficiency Syndrome: A Fatal Case Report Evolving Into Cutaneous Squamous Cell Carcinoma and EBV‐Associated Lymphoproliferative Syndrome

ABSTRACT Transporter associated with antigen presentation (TAP) deficiency syndrome (TDS) is a rare primary immunodeficiency (PID) characterised by a broad spectrum of clinical manifestations, with noninfectious cutaneous granulomas (CG) being a common feature. We present a case of TDS caused by a novel TAP1 mutation, diagnosed after nearly three decades of follow‐up, based on the identification of distinctive skin lesions. Notably, this case is associated with cutaneous rubella virus (RV) replication, a finding previously reported in other PIDs, but only once in TDS, making this the second documented instance of its kind. Moreover, this is the first documented case of CG transforming into invasive squamous cell carcinoma (iSCC) and progressing to Epstein‐Barr virus (EBV)‐associated lymphoproliferative disease (EBV‐LPD), ultimately leading to the patient's death.