Clinical features and pathological analysis of primary rib Langerhans cell histiocytosis: case series and literature review.

Background: Langerhans cell histiocytosis (LCH) is a rare histiocytic neoplasm characterized by the abnormal proliferation of Langerhans cells, which can infiltrate various tissues throughout the body, leading to a spectrum of organ damage. This study aims to explore the clinical characteristics, imaging manifestations, and pathological features of the disease to enhance clinical diagnosis and understanding of such conditions. Case Description: This study reviews the clinical data of four patients diagnosed with LCH at The First Affiliated Hospital of Hunan University of Traditional Chinese Medicine. All patients met the diagnostic criteria outlined in the LCH guidelines by the American Society of Hematology, with Langerhans cells expressing CD1a, S-100, and Langerin (CD207). Conclusions: LCH can involve various organs and systems, presenting with diverse clinical manifestations; in particular, rib Langerhans cell histiocytosis (RLCH) primarily manifests as asymptomatic or mildly painful bone swelling. Computerized tomography (CT) imaging of RLCH typically reveals localized masses and focal bone destruction, with or without surrounding soft tissue invasion. Conversely, magnetic resonance imaging provides a clearer assessment of lesion size and the extent of adjacent soft tissue involvement, offering advantages in guiding surgical excision. Diagnosis requires correlation with pathological and immunohistochemical results. For single-system, single-site (SS-s LCH), R0 surgical resection is feasible; however, single-system, multi-site (SS-m LCH) cases necessitate combined chemotherapy or targeted therapies. Overall, the treatment outcomes for this disease remain reasonably favorable.