An unexpected finding in the frontal sinus: Cholesterol granuloma

There is a broad differential diagnosis for patients presenting with an expansile mass lesion in the frontal sinus on computed tomography. Due to the composition of granulation tissue, a cholesterol granuloma exhibits unique signal characteristics and should be considered when an expansive paranasal sinus mass with high signal intensity on both T1- and T2-weighted images is seen. A cholesterol granuloma is a benign tumor, and small lesions are mostly harmless. However, large cholesterol granuloma may cause severe morbidity and even mortality if unrecognized, by extension through the orbit and in the anterior cranial fossa, emphasizing the importance of early diagnosis and resection. We present the case of a young male with an expanding mass under the right eyebrow, proved to be a cholesterol granuloma on pathological examination. The differential diagnosis and the distinct radiological features of this rare entity are discussed.