Langerhans cell histiocytosis with lung involvement in isolation and multisystem disease: staging, natural history, and comparative survival.

Abstract

Langerhans cell histiocytosis (LCH) is a histiocytic neoplasm that can involve the lungs as single system (LCH-SSL) or multi-system disease (LCH-MSL). The role of full-body radiographic staging to determine whether patients have LCH-SSL or LCH-MSL is unclear. Long term outcomes of LCH-SSL versus LCH-MSL and LCH-MSNL (multisystem without lung involvement) are unknown. A retrospective study of adult LCH patients seen at our center from January 2000-2020 was performed. In Part 1, we addressed utility of whole-body staging imaging among those presenting with isolated pulmonary signs or symptoms. Staging was defined as FDG-PET/CT or whole-body CT obtained within three months of diagnosis. In Part 2, we examined the frequency of developing extra-pulmonary disease over time and mortality in patients with LCH-SSL. In Part 3, we compared the overall survival of LCH-SSL, LCH-MSL, and LCH-MSNL. Part 1: 240 patients with LCH were identified. 112 (47%) had pulmonary signs or symptoms at presentation. 34 (30%) underwent radiographic staging and only one showed evidence of extra-pulmonary disease. Part 2: 108 (45%) were LCH-SSL. Median follow-up duration of 4.5\u2009years (95% CI: 2.9-6.0). None developed extra-pulmonary disease. Part 3: 5-year survival: 94% (95% CI: 84-98%) for LCH-SSL, 78% (95% CI: 59-90%) for LCH-MSL, and 75% (95% CI: 53-89%) for LCH-MSNL. LCH patients presenting with isolated pulmonary signs or symptoms rarely have extra-pulmonary involvement at the time of diagnosis and generally do not develop extra-pulmonary progression. LCH-SSL has the best overall survival, while LCH-MSL and LCH-MSNL have similar clinical outcomes. This article is protected by copyright. All rights reserved.