Screening for Endolymphatic Sac Tumor

Of all the people with VHL seen at the U.S. National Cancer Institute, roughly 10% develop an endolymphatic sac tumor (ELST). 10% of those (1% of people with VHL) develop tumors on both sides.

With early detection, hearing loss can be prevented in many people. There is a reasonable chance that a skilled surgeon can remove a small ELST and not damage the inner ear. Once an ear tumor gets large, though, it is much more likely that the inner ear will need to be sacrificed to remove the tumor completely, which is the only successful long-term treatment.

Awareness of VHL and ELST is still problematic, even though there are more case reports describing the relationship between them.

The most important thing for people with VHL to know is that routine screening for VHL will likely not find an ELST. While most individuals affected by VHL get routine brain MRIs (if they are in a good surveillance program), regular MRIs of the brain typically use a slice depth of 5 mm through the brain region. Slice depth or "cut" refers to the distance between the pictures. Images may be captured that include the inner ear region where an ELST can develop, but the small sac in which an ELST usually develops is only 1-2 mm in size, so there is a reasonable chance that these pictures, 5 mm apart, might "skip over" or not pick up the early ELST. If an ELST is suspected, dedicated MRIs of the internal auditory canal region with gadolinium contrast, usually with 1 mm "cuts" through the level of the inner ear, are the best way of detecting an early ELST.

Obviously, its not practical to order this detailed time-consuming and expensive scan on every person, so clinical suspicion and judgement have to be employed. If individuals complain to their doctor that they are experiencing episodes of vertigo, hearing loss, tinnitus (noises in their ear), a sense of fullness or pressure in their ear or perhaps facial weakness on one side, then a dedicated MRI of the internal auditory canal region is indicated. Even after such a scan is ordered, its necessary for the interpreting radiologist and other physicians to be aware of the possibility of an ELST and also to look for it on the scan. Sometimes a correlative CT scan of the same region can be helpful in confirming a possible ELST.

Related articles: Erika's Story - ELST as diagnostic of VHL