2024 Asia Conference on Lung Cancer (ACLC) - Poster & ePosters-PP01.64

PP01.64 - Nuruddin Mohammad Iqbal

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The document details two challenging cases of non-Langerhans cell histiocytosis presented at the All India Institute of Medical Sciences, New Delhi. These disorders, not fitting criteria for Langerhans cell histiocytosis or hemophagocytic lymphohistiocytosis, exhibit diverse clinical presentations and diagnostic complexities.<br /><br />**Case 1:** A 61-year-old female experienced dyspnea, hoarseness, and neck swelling. Radiological examination revealed a mediastinal mass extending to the neck. Histopathology showed dense fibrosis with lymphocytes and numerous histiocytes, suggestive of a non-Langerhans cell histiocytosis, possibly Erdheim-Chester disease. Molecular tests showed a likely pathogenic BRAF mutation. The patient showed improvement with vinblastine and prednisolone treatment.<br /><br />**Case 2:** A 21-year-old female presented with chronic cough and shortness of breath. Initially misdiagnosed with pulmonary tuberculosis, imaging revealed a FDG-avid mass involving the tracheobronchial tree. Histological analysis demonstrated numerous histiocytes with emperipolesis, indicating a diagnosis of Rosai-Dorfman disease. No infectious organisms were found, confirmed by negative special stains.<br /><br />Both cases underscore the complexity of diagnosing non-Langerhans histiocytic disorders. **Rosai-Dorfman disease** involves S100-positive histiocytes and is rare, with intrathoracic manifestations in 2% of cases. **Erdheim-Chester disease** commonly affects long bones and rarely the lungs, requiring careful screening for associated conditions. Accurate diagnosis relies on high suspicion, thorough morphological review, and adjunct tests, with clinic-radiological correlation essential for appropriate treatment. The identification and understanding of such diseases remain a diagnostic challenge due to their rarity and varied clinical presentations.

Keywords

non-Langerhans cell histiocytosis

Erdheim-Chester disease

Rosai-Dorfman disease

BRAF mutation

vinblastine

prednisolone

diagnostic challenge

S100-positive histiocytes

intrathoracic manifestations

clinic-radiological correlation