Erdheim-Chester Disease Revealed by Central Positional Nystagmus: A Case Report

Abstract

Erdheim-Chester disease (ECD) is a rare histiocytic disorder, recently recognized to be neoplastic. The clinical phenotype of the disease is extremely heterogeneous, and depends on the affected organs, with the most frequently reported manifestations being bone pain, diabetes insipidus and neurological disorders including ataxia. In this article, we report on a case of a 48-year-old woman, whose initial symptom of gait instability was isolated. This was associated with positional nystagmus with central features: nystagmus occurring without latency, clinically present with only mild symptoms, and resistant to repositioning maneuvers. The cerebral MRI showed bilateral intra-orbital retro-ocular mass lesions surrounding the optic nerves and T2 hyperintensities in the pons and middle cerebellar peduncles. A subsequent CT scan of the chest abdomen and pelvis found a left "hairy kidney", while ¹⁸ F-FDG PET-CT imaging disclosed symmetric 18F-FDG avidity predominant at the diametaphyseal half of both femurs. Percutaneous US-guided biopsy of perinephric infiltrates and the kidney showed infiltration by CD68(+), CD1a(-), Langerin(-), PS100(-) foamy histiocytes with BRAF ^V600E mutation. The combination of the different radiological abnormalities and the result of the biopsy confirmed the diagnosis of ECD. Many clinical and radiological descriptions are available in the literature, but few authors describe vestibulo-ocular abnormalities in patients with ECD. Here, we report on a case of ECD and provide a precise description of the instability related to central positional nystagmus, which led to the diagnosis of ECD.

Keywords: Erdheim-Chester disease; case report; central positional nystagmus; dizziness; gait; nystagmus.

Figure 1

Brain MRI. (A) Axial CISS was normal for internal auditory canals and cerebellopontine angles, but incidentally depicted bilateral intra-orbital mass lesions (stars). (B,C) Axial spin echo T2-weighted images revealed hyperintensities in the pons and the middle cerebellar peduncles (arrowheads) and demonstrated bilateral hypointense retro-ocular mass lesions (arrows). (D) Axial post-gadolinium T1-weighted image, these lesions surrounded the optic nerves sheaths and were avidly enhanced (arrows).

Figure 2

FDG-PET/CT, showing multifocal radiotracer uptake in the long bone marrow predominantly on the distal half of the femurs.

Figure 3

Axial CT-Scan showing dense infiltration of left perinephric adipose tissue (“hairy kidney”).

Figure 4

Pathological examination showed perirenal fat and kidney capsule infiltrate made up of histiocytes, some of them with foamy cytoplasm (hematein-eosin-saffron, original magnification, x100).