Shane Eaton


Shane Eaton1, Liesly Lee2, Zachary Feilchenfeld3, Chris Heyn4, Cynthia Hawkins1,5, Julia L. Keith1,6

1 Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada

2 Department of Medicine, Division of Neurology, Sunnybrook Health Sciences Centre and University of Toronto, Toronto, ON, Canada

3 Department of Medicine, Division of Internal Medicine, Sunnybrook Health Sciences Centre and University of Toronto, Toronto, ON, Canada

4Department of Diagnostic Imaging, Sunnybrook Health Sciences Centre, Department of Medical Imaging, University of Toronto, Toronto, ON, Canada

5 Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, ON, Canada

6 Laboratory medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Clinical Summary

This 71 year old woman with a past medical history of coronary artery disease presented with a variety of neurologic symptoms. These included a two year history of slowly progressive slurred speech and left hand clumsiness. Over the few months prior to presenting to hospital she also developed weakness and gait difficulties with multiple falls followed by diplopia and weight loss. MRIs of the brain demonstrated progressive, ill-defined T2/T2 FLAIR hyperintensity within the midbrain, hippocampi, pons, brachium pontis and cerebellar white matter. On post-gadolinium sequences there were punctate foci of enhancement within the midbrain tegmentum. The differential diagnosis for the imaging findings included rhombo-cerebellar-limbic encephalitis. Extensive workup was negative, including CSF and serology for paraneoplastic and autoimmune encephalitis associated antibodies. Systemic imaging showed sclerotic bony lesions in the right ilium, femur and the T12 vertebral body originally thought to represent widespread metastases from an unknown primary. Biopsies of her T12 vertebral body had been reported at a community hospital as negative for carcinoma and multiple myeloma. Her symptoms did not improve on steroids or a course of IVIG. Given the complexities of her clinical presentation and lack of an established unifying diagnosis a pathology review of the bone biopsies was requested.

Discussion points

  1. Diagnosis, and how would you confirm this?
Reveal Diagnosis

Case of Erdheim-Chester Disease

Additional relevant investigations and comment.
Positive for BRaf V600E mutation

1. Ozkaya N et al. The histopathology of Erdheim-Chester disease: a comprehensive review of a molecularly characterized
cohort. Mod Pathol 2018 Apr;31(4):581-597.
2. Aubart FC et al. Histiocytosis and the nervous system: from diagnosis to targeted therapies. Neuro Oncol 2021 Sep