Adult Onset Langerhans Cell Histiocytosis: Clinical Characteristics and Treatment Outcomes

PURPOSE

Langerhans cell histiocytosis (LCH) is a rare disease that can affect all tissues and organs. Our study evaluated the clinical characteristics and treatment outcomes of adult-onset LCH patients in a tertiary center.

MATERIALS AND METHODS

Adult patients diagnosed with LCH were retrospectively evaluated. Their initial symptoms, stratification according to disease involvement, treatment details, treatment responses, and overall and progression-free survival (PFS) were analyzed.

RESULTS

Thirty-three patients were included. There were 21 single system LCH, 10 multisystem LCH, and 2 pulmonary LCH patients. Patients with single system unifocal involvement were successfully treated with local therapies such as surgery and radiotherapy. Most of the multisystem LCH patients and patients with single system multifocal involvement were treated with systemic chemotherapy. Cladribine was the first choice in 10 out of 11 patients who received chemotherapy. Among all patients, the overall response rate (ORR) was 97%. Among those who had cladribine in the first-line the ORR was 81%. All these patients achieved a complete remission and were alive at the last visit. The median follow-up was 38 (range, 2-183) months. The median PFS has not yet been reached. Ten-year PFS was 90.9%.

CONCLUSION

Besides successful local treatments with surgery and radiotherapy, our study provides information for front-line cladribine treatment.

International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults

Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.

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

Langerhans cell histiocytosis (LCH) is a histiocytic neoplasm that can involve the lungs as single system (LCH-SSL) or multisystem 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 multisystem without lung involvement (LCH-MSNL) are unknown. A retrospective study of adult LCH patients seen at our center from January 2000 to 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 fluorodeoxyglucose positron emission tomography-computed tomography (CT) or whole-body CT obtained within 3 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. A total of 112 (47%) had pulmonary signs or symptoms at presentation. Thirty-four (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 years (95% confidence interval [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.

The Mayo Clinic Histiocytosis Working Group Consensus Statement for the Diagnosis and Evaluation of Adult Patients With Histiocytic Neoplasms: Erdheim-Chester Disease, Langerhans Cell Histiocytosis, and Rosai-Dorfman Disease

Histiocytic neoplasms, a rare and heterogeneous group of disorders, primarily include Erdheim-Chester disease, Langerhans cell histiocytosis, and Rosai-Dorfman disease. Due to their diverse clinical manifestations, the greatest challenge posed by these neoplasms is the establishment of a diagnosis, which often leads to a delay in institution of appropriate therapy. Recent insights into their genomic architecture demonstrating mitogen-activated protein kinase/extracellular signal-regulated kinase pathway mutations have now enabled potential treatment with targeted therapies in most patients. This consensus statement represents a joint document from a multidisciplinary group of physicians at Mayo Clinic who specialize in the management of adult histiocytic neoplasms. It consists of evidence- and consensus-based recommendations on when to suspect these neoplasms and what tests to order for the diagnosis and initial evaluation. In addition, it also describes the histopathologic and individual organ manifestations of these neoplasms to help the clinicians in identifying their key features. With uniform guidelines that aid in identifying these neoplasms, we hope to improve the awareness that may lead to their timely and correct diagnosis.