MR imaging of cheek lesions of Kimura’s disease: Focusing on the signal abnormalities and the relationship with superficial musculoaponeurotic systems

Abstract

Background and Purpose: Kimura's Disease (KD) is a rare benign chronic eosinophlic inflammatory disorder, characterized by angiolymphoid proliferation with peripheral eosinophilia and elevated serum immunoglobulin E. Most lesions occur in the head and neck regions. To the best of our knowledge, the relationship between subcutaneous cheek lesion of KD and the surrounding structures including superficial musculoaponeurotic systems (SMAS) has never been reported. The purpose of this study was to describe MR imaging findings of cheek subcutaneous lesion of KD and adjacent SMAS. Materials and Methods: Seven cheek subcutaneous lesions of 5 patients histopathologically proved KD were evaluated. We retrospectively evaluated the MR imaging findings of subcutaneous lesions for signal intensity in each imaging sequence, the border of the lesions, and appearance of SMAS. Results: All cheek lesions were displacing normal fat tissue. These lesions showed ill-defined border (7/7), slightly high signal intensity on T1-weighted images (7/7), and intermediate (1/7) or high signal intensity (6/7) on T2-weighted images. Cheek lesions were enhanced by intravenous injection of gadolinium to signal intensity close to that of fat tissue (3/4), and in one case, the avid enhancement of the mass was seen (1/4). All lesions attached to the outer surface of SMAS, however, only one out of 7 lesions distributed below the SMAS without tearing of the layers. SMAS below the lesion showed high signal intensity on T2-weighted images in two lesions (2/7). Conclusion: KD should be included in the differential diagnosis when a cheek mass presents with non-specific signal intensities and irregular border, which attaches to but does not interrupt SMAS on MR imaging.