DEC 08, 2014
The authors report a case of Erdheim-Chester disease (ECD) with visual loss due to compression of the optic chiasm by a refractory suprasellar lesion in which normal vision was recovered within one month of starting vemurafenib therapy.
ECD is a rare non–Langerhans cell histiocytosis characterized by the accumulation of foamy CD68+CD1a− histiocytes. Tissue infiltration preferentially affects long bones and retroperitoneal and peri-aortic spaces, but almost any organ or system can be affected.Cardiac and neurologic involvements are associated with significantly higher levels of mortality and morbidity.
The patient, a 58-year-old man, was refractory to conventional treatment with interferon-α. However, treatment with vemurafenib—a selective low-molecular-weight BRAF gene mutation kinase inhibitor effective for metastatic melanoma, including cerebral metastases—induced a major clinical and metabolic response within one month. More than half of ECD patients have the BRAF mutation.
On day 10 of vemurafenib treatment, the patient’s vision had improved to 1.0 in both eyes from 0.7 and 0.8 in the left and right eyes, respectively, before this treatment, and the visual field was normal. His cerebral PET scan after treatment was normal and tumor size had decreased.
The authors write that although ECD lesions may tend to regress spontaneously, the dramatic improvement seen in this case is likely due to vemurafenib since the suprasellar mass had been growing continuously in the preceding months. They say that the response in this case is striking since it led to the cancellation of surgery.
They conclude that the targeted inhibition of mutant BRAF kinase could become the preferred first-line treatment for ECD at life-threatening sites.