The Unusual Ultrasound Features of a Breast Cholesterol Granuloma Manifesting as an Intracystic Mass: Case Report and Literature Review
A 62-year-old woman with no previous history of breast disease was referred to our hospital from a local clinic. The patient complained of a painless, palpable mass in the lower, outer quadrant of her left breast; the mass had been present for 10 years. She exhibited no other clinical symptoms or other signs upon physical examination, and she had no history of having undergone a breast biopsy or chest wall trauma.\nMammography results revealed a well-circumscribed, round mass in the lower, outer quadrant of the left breast. The mass was generally of high density and had a peripheral radiolucent rim, with scattered coarse, heterogeneous calcifications present ().\nOn ultrasonography, a 5 × 4.6 cm circumscribed, oval, complex echoic mass was observed in the left breast, at the 4 o'clock position (). Within this cystic mass, there was a lobular, solid lesion of approximately 2 cm in diameter with floating, hyperechoic internal contents. No increased vascularity was visible on color Doppler imaging (). The lesion met the criteria for Breast Imaging Reporting and Data system category 4a, and we therefore recommended a core needle biopsy.\nUltrasound-guided core needle biopsy of the mass was performed with a 14-gauge needle. The mass collapsed after biopsy, and the residual lesion measured 3.7 × 0.8 cm ().\nAlthough the mass in the left breast was confirmed to be benign, we performed a resection in order to alleviate the patient's symptoms. The resected tumor was determined to be a cholesterol granuloma. The surgical specimen measured 4.5 × 4.0 cm and was primarily composed of cystic material with internal brown, necrotic material (). Microscopic examination revealed a thick, fibrous cystic wall, with characteristic cholesterol crystals arranged in parallel or radial arrays, and aggregates of histiocytes (). Hemorrhage (both fresh and old) and fat necrosis were also noted.