Bilateral Ground-Glass Opacities as an Initial Manifestation of iMCD-TAFRO Syndrome: Diagnostic Insights from a Case with Negative Lung Biopsy Findings.

Idiopathic multicentric Castleman disease with TAFRO syndrome (iMCD-TAFRO) rarely involves the lungs. We report the case of a 50-year-old man with persistent gastrointestinal symptoms who was found to have bilateral ground-glass opacities on chest CT. Despite prominent imaging abnormalities, a bronchoscopic lung biopsy revealed no inflammatory changes in the lungs. Bone marrow and lymph node biopsies confirmed the diagnosis of iMCD-TAFRO. Treatment with tocilizumab and corticosteroids resulted in clinical remission for 3 years. Pulmonary manifestations likely reflect secondary fluid retention rather than primary lung disease. This illustrates the importance of performing comprehensive tissue evaluations beyond a lung biopsy when systemic symptoms are accompanied by pulmonary findings.