Langerhans Cell Histiocytosis Presenting Primarily as Cervical Lymphadenopathy: A Diagnostic Challenge in Tuberculosis-Endemic Regions

Abstract

Introduction: Langerhans Cell Histiocytosis (LCH) is an uncommon clonal proliferative disorder of antigen-presenting dendritic cells, predominantly affecting children. It presents with a wide clinical spectrum, ranging from localized bone or skin involvement to disseminated multisystem disease. Cervical lymphadenopathy is unusual and often mimics infectious or lymphoproliferative conditions, making diagnosis challenging.

Aim & Objective: To highlight an unusual presentation of LCH as bilateral cervical lymphadenopathy with skull lesions, and to emphasize the diagnostic utility of fine needle aspiration cytology (FNAC) with cell block immunohistochemistry in distinguishing it from mimickers.

Case Presentation: A one-and-a-half-year-old girl presented with bilateral cervical lymphadenopathy and intermittent fever for four months. Clinical and radiological evaluation was performed. FNAC from cervical lymph nodes with cell block preparation and immunohistochemistry was undertaken.

Results: Cytological smears showed numerous atypical histiocytes with vesicular nuclei, nuclear grooves, and abundant pale cytoplasm, accompanied by eosinophils, lymphocytes, and multinucleated giant cells. Immunohistochemistry revealed positivity for S100 and CD68, supporting the diagnosis of LCH. Radiological imaging demonstrated lytic lesions in the frontal and parietal skull bones. Based on cytomorphology, immunohistochemistry, and radiological correlation, a final diagnosis of LCH was made.

Conclusion: This case highlights the diagnostic challenge posed by LCH with unusual lymph node involvement. Its clinical resemblance to tuberculosis, lymphoma, or Rosai-Dorfman disease often leads to misdiagnosis. FNAC, aided by immunohistochemistry, plays a pivotal role in early recognition. Early diagnosis is crucial as clinical behavior ranges from self-limiting lesions to aggressive multisystem disease requiring chemotherapy. Awareness of atypical presentations prevents diagnostic delays and improves patient outcomes.