Clinical features, genomic profiling, and outcomes of adult patients with unifocal Langerhans cell histiocytosis.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare highly heterogeneous histiocytosis, which can be divided into single system and multiple system disease according to site of involvement. There is a paucity of studies examining unifocal LCH in adults in the molecular era. RESULTS: We retrospectively analysed records from 70 patients with unifocal LCH. The median age at diagnosis was 36 years (18-69). The most common organ involved was the bone (70.0%), followed by pituitary gland (7.1%). Target gene sequencing of lesion tissues was performed on 32 of the 70 patients. MAPK/PI3K pathway alterations were observed in 78.1% of the patients; the most common mutations included BRAFV600E (28.1%), MAP2K1 (18.8%) and PIK3CA (9.4%). After a median follow-up time of 39.4 months (0.7-211.8), 10 (14.3%) patients developed disease progression, of whom 4 had local recurrence, 2 progressed to single-system multifocal and 4 progressed to multiple system LCH. The 3-year progression-free survival (PFS) was 81.9%. Univariate analysis showed that age < 30 years at diagnosis was associated with worse 3-year PFS (52.2% vs. 97.0%, p = 0.005). The 3-year overall survival was 100%. CONCLUSIONS: In our large cohort of adults with unifocal LCH, we found that prognosis of unifocal LCH in adults was very good, and age < 30 years at diagnosis was associated with increased relapse risk.

The clinical spectrum and prognostic factors of Erdheim-Chester disease and mixed Langerhans cell histiocytosis and Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a rare and probably fatal multisystemic non-Langerhans cell histiocytosis (LCH). To comprehensively investigate the clinical features, genomic analysis, treatments, and prognostic factors of ECD, we retrospectively analyzed the clinical data of 75 ECD patients and 10 mixed LCH and ECD patients in our center. The median age at diagnosis was 46 years (range, 5-70). ECD patients were older at diagnosis (p = 0.006) and had more cardiac involvement (p = 0.011) as well as vascular (p = 0.031) involvement compared to mixed LCH and ECD patients. 64.8% of ECD patients and 87.5% of mixed LCH and ECD patients carried BRAFV600E mutation. The BRAFV600E mutation correlated with a greater number of affected organs (p = 0.030) and was associated with lung involvement (p = 0.033) as well as pleural involvement (p = 0.002). The median follow-up time was 38 months (range, 1-174). The estimated 5-year progression-free survival (PFS) and overall survival (OS) were 48.9% and 84.7%, respectively. In a multivariate analysis, right atrial pseudotumor (p = 0.013) and pancreatic involvement (p = 0.005) predicted worse OS, while pleural (p = 0.042) and central nervous system (CNS) involvement (p = 0.043) predicted worse PFS. Our study described the clinical spectrum of ECD and mixed LCH and ECD, while also revealed the prognostic value of right atrial pseudotumor and pancreatic, pleural, and CNS involvement for worse survival.

Pancreatic involvement in Erdheim-Chester disease: a case report and review of the literature.

BACKGROUND: Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by infiltration of lipid-laden foamy macrophages within different tissues. Clinical manifestations of ECD are highly heterogeneous. Bone lesions are found in 80%-95% of patients, while extraosseous lesions usually involve the cardiovascular system, retroperitoneum, central nervous system (CNS), and skin. Pancreatic involvement in ECD has barely been reported. CASE PRESENTATION: A 29-year-old female initially presented with menoxenia, diabetes insipidus and diabetes mellitus. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) revealed hypermetabolic foci in the bilateral frontal lobe, saddle area, and pancreas. A 99mTc-MDP bone scrintigraphy scan revealed symmetrical increased uptake in distal femoral and proximal tibial metaphysis, which was confirmed to be osteosclerosis by high-resolution peripheral quantitative computed tomography. The patient underwent incomplete resection of the sellar mass. Histological examination of biopsies showed histiocytic aggregates, which were positive for S100 and negative for CD1a and CD207 on immunohistochemistry. Enhanced abdominal CT scan showed hypointense nodules within the body and tail of the pancreas. Endoscopic ultrasonography guided fine-needle aspiration (EUS-FNA) found no evidence of malignancy. She was diagnosed with ECD and treated with high-dose IFN-α. Repeated examinations at three-and eight-months post treatment revealed markedly reduction of both intracranial and pancreatic lesions. CONCLUSIONS: ECD is a rare histiocytic neoplasm that can involve almost every organ, whereas pancreatic involvement has barely been reported to date. Here, we present the rare case of pancreatic lesions in ECD that responded well to interferon-α. We further reviewed reports of pancreatic involvement in histiocytic disorders and concluded the characteristics of such lesions to help diagnosis and treatment, in which these lesions mimicked pancreatic adenocarcinoma and caused unnecessary invasive surgeries.