Multiple Organ Involvement in a Boy with Lipopolysaccharide-Responsive Beige-like Anchor Protein Deficiency Detected by F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Patients with pathogenic variants of <i>lipopolysaccharide-responsive beige-like anchor protein</i> (<i>LRBA</i>) are known to present with autoimmune diseases, inflammatory bowel disease, lymphoproliferative disorders, allergies, immunodeficiency, and malignancies. This condition, characterized by widespread infections that impact multiple systems, has various radiological findings reported in the literature. These include computed tomography (CT) findings indicating lung involvement and magnetic resonance imaging (MRI) findings showing neurological system involvement. However, F-18 fluorodeoxyglucose positron emission tomography-CT (FDG PET-CT) imaging findings in <i>LRBA</i> deficiency have not yet been described in the literature. This report presents multiple organ involvements detected by F-18 FDG PET-CT in a case with an <i>LRBA</i> gene variant. FDG PET-CT findings for diagnostic and primary focus evaluation were reviewed in a 17-year-old male patient with a pathogenic <i>LRBA</i> variant, prompted by multiple hypoechoic nodular appearances identified on abdominal ultrasonography. In this patient, who carried a pathogenic <i>LRBA</i> variant (c.3396-3397delAC, p.D975Yfs*15) and was treated with abatacept for liver involvement, FDG PET-CT revealed a wide range of system involvements. These included the lungs, liver, intestines, bone, bone marrow, and lymph nodes, as well as multiple joints and tendons. In immunodeficiency diseases with such extensive multisystem involvement, whole-body imaging techniques like F-18 FDG PET-CT can serve as valuable tools for physicians to comprehensively assess the disease and formulate effective treatment strategies.