Case Presentation: Large Diffuse B-cell Lymphoma Developing in the Context of Primary Immunodeficiency

Ataxia Telangiectasia (AT) is a rare, autosomal recessive neurodegenerative disorder characterized by immunodeficiency. Clinically, it is known to be associated with progressive cerebellar ataxia starting in early childhood, oculocutaneous telangiectasia, cellular and humoral immunodeficiency, and an associated increased risk of cancer. A 9-year-old female patient diagnosed with ataxia telangiectasia presented to the immunology outpatient clinic with complaints of difficulty breathing and snoring. Examination revealed an ulcerative vegetative mass obstructing the airway in the palate. The patient also presented with white plaques on her tongue, raising the possibility of fungal infection or lymphoproliferative disease. A biopsy of the palatal lesion was performed, and the patient was diagnosed with Diffuse Large B-Cell Lymphoma. Cultures from the biopsy also revealed simultaneous Candida albicans growth. This case highlights the increased risk of lymphoproliferative disorders in patients with primary immunodeficiency due to Ataxia Telangiectasia, which may present with a range of clinical manifestations. In this patient group, there is a potential association with invasive infections and malignancy, underscoring the need for clinicians to consider further investigations and, if necessary, perform a biopsy to support the diagnosis in cases of clinical suspicion.