The Role of Staging Evaluation at Initial Diagnosis of Adult Patients with Clinically Isolated Pulmonary Langerhans Cell Histiocytosis
▪ Background: Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder that is now recognized as a neoplasm by the World Health Organization. It is generally classified based on the site and extent of disease involvement (single system or multisystem). Pulmonary LCH (pLCH), an unc...
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| Published in: | Blood 2020-11, Vol.136 (Supplement 1), p.45-45 |
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| Main Authors: | , , , , , , , , , , , , , , |
| Format: | Article |
| Language: | eng |
| Online Access: | Get full text |
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| Summary: | ▪
Background: Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder that is now recognized as a neoplasm by the World Health Organization. It is generally classified based on the site and extent of disease involvement (single system or multisystem). Pulmonary LCH (pLCH), an uncommon interstitial lung disease associated with smoking, often presents as isolated pulmonary disease. It is unclear whether patients with clinically isolated pLCH have extra-pulmonary lesions at diagnosis or during the course of their disease. The role of [18F] fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET-CT) in the staging of pLCH remains unclear. Our study aims to better characterize the utility of radiographic staging studies at time of diagnosis and prevalence of extrapulmonary disease at follow up in pLCH.
Methods: We conducted a retrospective study of patients presenting with clinical findings consistent with isolated pLCH seen at the Mayo Clinic from January 2000 to January 2020. All patients had a diagnosis of pLCH determined by chest imaging studies [computed tomography (CT) or high-resolution CT (HRCT)] or by histopathologic findings from surgical or transbronchial lung biopsy. Histopathologic findings for the diagnosis of pLCH required the presence of Langerhans cells (S100+/CD1a+/Langerin+). Patients were excluded if they had clinically apparent extra-pulmonary organ involvement at the time of diagnosis. BRAF V600E mutation was determined by immunohistochemistry (IHC) or cell-free DNA (cfDNA). Staging was defined as FDG-PET-CT or whole body CT imaging obtained within 3 months of diagnosis of pLCH. Extra-pulmonary LCH involvement was determined by imaging characteristics or by histopathologic findings. Descriptive statistics and overall survival (OS) were analyzed with JMP software, version 14 (SAS Institute Inc., Cary, NC).
Results: A total of 112 patients with clinically isolated pLCH were identified. The median age at diagnosis was 45 years (range 21-73), and 48 (43%) were male. The majority (n=110, 99%) were former or current smokers with a median pack year of 25 (range 1-57). Three (3%) patients were noted to have occupational industrial exposure. Nine patients had a history of another cancer prior to their diagnosis and staging of pLCH [lung (n=4), breast (n=2), neuroendocrine (n=2), thyroid (n=1)]. Presenting symptoms included dyspnea on exertion 49 (44%), cough 18 (16%), chest pain 14 (13%), and 29 (28%) were i |
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| ISSN: | 0006-4971 1528-0020 |