Cyst or Keloid: A Case Report of Radiologic Confusion in a 76-Year-Old Female

A 76-year-old female presented to primary care procedure clinic for excision of a suspected sebaceous cyst. Ultrasound prior to the procedure revealed a hypoechoic lesion with inflammatory features. This image was compared to a previous fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) which was obtained for a separate indication. The lesion was noted to have an abnormal FDG uptake. The procedure revealed that this lesion was not consistent with a cyst, rather, clinically consistent with a keloid. This case is of interest in that there was no underlying known injury or aggravating factor leading to the formation of the keloid. We propose that keloids should be included in the differential diagnosis of subcutaneous nodules even in the case of unknown local trauma or injury and in the setting of signs of inflammation on ultrasound or FDG-PET.ObjectiveDescribe the case of a suspected inflamed sebaceous cyst, demonstrating FDG-PET avidity which subsequently was found to be clinically consistent with a keloid. This case report is exempt from institutional review board approval.