Erdheim-Chester disease, moving away from the orphan diseases: A case report

Role of 18 F-FDG PET/CT in Erdheim-Chester Disease in the Era of Multimodality Imaging

Erdheim–Chester disease is a rare disease with systemic non-Langerhans cell histiocytosis, the diagnosis of which with conventional imaging modalities is challenging. We describe a case of a 73-year-old woman who was referred with a progressive history of bilateral proptosis. The magnetic resonance imaging (MRI) orbit demonstrated bilateral orbital masses with optic nerve encasement. A subsequent 18F-FDG PET/CT scan showed multi-organ disease with involvement of the orbits, pericardium, aorta, pararenal fascia, and appendicular bones. Metabolically active, easily accessible areas were selected for CT-guided biopsy. The biopsy showed sheets of foamy histiocytes with the expression of CD 68 and CD 163 consistent with a diagnosis of Erdheim–Chester disease. The FDG PET/CT played a pivotal role in establishing the diagnosis with the assessment of disease extent and further guided in the targeted biopsy.

Erdheim-Chester disease: a comprehensive review from the ophthalmologic perspective

Erdheim-Chester disease (ECD) is a rare clonal histiocytic neoplasm with less than 1200 documented cases to date. The disease is life-threatening and difficult to recognize, although increasing awareness as well as the integration of clinical, imaging, pathology information , and genetic studies have led to a recent exponential increase in new reported cases. ECD affects multiple organs and systems, including skeletal, neurologic, and cardiovascular. Pulmonary, retroperitoneal, and cutaneous lesions have also been reported in various combinations. Until the discovery that more than half of ECD patients harbor the BRAF-V600E mutation or other mutations in the mitogen-activated protein kinase (MAPK) and RAS pathways, Interferon-a was the first-line treatment. Nowadays BRAF and MEK-inhibitors targeted therapies are the mainstay of treatment. Ophthalmologic involvement occurs in 25% -30% of ECD cases, usually in the form of orbital involvement presenting with exophthalmos and ophthalmoplegia. Other ophthalmologic manifestations include palpebral xanthelasmas, anterior uveitis and vitritis, optic disk edema, choroidal infiltration, recurrent serous retinal detachment, retinal drusen-like deposits and retinal pigment epithelial changes. ECD patients can also present with ocular symptoms as a result of adverse effects of the treatment regimens. In some cases with smoldering or protean symptoms, the emergence of eye manifestations triggered the diagnosis. Ophthalmologists have to be aware of the disease, recognize the constellation of ECD symptoms, and contribute to the diagnosis, treatment, and follow-up of ECD patients.

18F-FDG PET/CT versus anatomic imaging for evaluating disease extent and clinical trial eligibility in Erdheim-Chester disease: results from 50 patients in a registry study

OBJECTIVES

The aim of this study was to [1] characterize distribution of Erdheim-Chester Disease (ECD) by 18F-FDG PET/CT and [2] determine the utility of metabolic (18F-FDG PET/CT) imaging versus anatomic imaging (CT or MRI) in evaluating ECD patients for clinical trial eligibility.

METHODS

18F-FDG PET/CT and corresponding CT or MRI studies for ECD patients enrolled in a prospective registry study were reviewed. Sites of disease were classified as [1] detectable by 18F-FDG PET only, CT/MRI only, or both and as [2] measurable by modified PERCIST (mPERCIST) only, RECIST only, or both. Descriptive analysis was performed and paired t test for between-group comparisons.

RESULTS

Fifty patients were included (mean age 51.5 years; range 18-70 years). Three hundred thirty-three disease sites were detected among all imaging modalities, 188 (56%) by both 18F-FDG PET and CT/MRI, 67 (20%) by 18F-FDG PET only, 75 (23%) by MRI brain only, and 3 (1%) by CT only. Of 178 disease sites measurable by mPERCIST or RECIST, 40 (22%) were measurable by both criteria, 136 (76%) by mPERCIST only, and 2 (1%) by RECIST only. On the patient level, 17 (34%) had mPERCIST and RECIST measurable disease, 30 (60%) had mPERCIST measurable disease only, and 0 had RECIST measurable disease only (p < 0.0001).

CONCLUSION

Compared with anatomic imaging, 18F-FDG PET/CT augments evaluation of disease extent in ECD and increases identification of disease sites measurable by formal response criteria and therefore eligibility for clinical trials. Complementary organ-specific anatomic imaging offers the capacity to characterize sites of disease in greater anatomic detail.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03329274.

Resolved heart tamponade and controlled exophthalmos, facial pain and diabetes insipidus due to Erdheim-Chester disease

A 69-year-old woman suffering from exophthalmos and facial pain came to us referred for aetiological diagnosis of exophthalmos. Orbital MRI showed thinned extrinsic ocular musculature, intraconal fat infiltration, retro-ocular compression and thickening of maxillary and sphenoid sinus walls. She had been suffering from diabetes insipidus for the last 7 years. During our diagnosis process, she presented signs of cardiac tamponade. Transthoracic heart ultrasound revealed large pericardial effusion and a heterogeneous mass that compressed the right ventricle. No osteosclerotic lesions on appendicular bones were present. Pericardiocentesis temporarily controlled tamponade and corticoid therapy temporarily abated exophthalmos. Pericardiectomy definitively resolved tamponade. Histological examination of pericardial tissue was conclusive of Erdheim-Chester disease. Exophthalmos responded to pegylated interferon-alpha-2a. Facial bone pain disappeared after zoledronic acid and interferon treatment. During interferon therapy, the patient suffered from a severe generalised desquamative exanthema that slowly resolved after discontinuing interferon. Diabetes insipidus remains controlled with desmopressin.