An Unusual Cause of CPAP Intolerance.

None: Continuous positive airway pressure (CPAP) is a first-line treatment for obstructive sleep apnea (OSA). However, the adherence to CPAP can be difficult for patients due to several reasons. In this case report we describe a patient with severe OSA who initially was treated successfully with CPAP, but after a few months adherence problems developed because of macroglossia. This was caused by amyloidosis due to multiple myeloma. During treatment with chemotherapy and stem cell transplantation, the size of the patient's tongue decreased and he could successfully use his CPAP device again.