Progressive lymphocytosis in familial hemophagocytic lymphohistiocytosis with lymphocytic interstitial pneumonia: a case report

Abstract Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically heterogeneous disorder which less typical in adults than pediatric patients. In this study, we reported rare case of adult-onset FHL3 with progressive lymphocytosis and lymphocytic interstitial pneumonia (LIP). A 20-year old female was admitted to our institution for persistent cough fever. chest high-resolution computed tomography (HRCT) scan showed diffuse bilateral ground glass opacities (GGO). lung biopsy revealed infiltration lymphocyte the pulmonary interstitium. The patient treated corticosteroids immunosuppressants, followed by significant clinical improvement although still persisted. definitive diagnosis FHL based on whole genome sequencing heterozygous mutations UNC13D gene were identified. Lymphocytosis may be remarkable feature some patients FHL. Performing important improve recognition avoid misdiagnosis.