A Case of Nodular Cystic Fat Necrosis: The End Stage Lesion Showing Calcification and Lipomembranous Changes

Nodular cystic fat necrosis, first described by Przyjemski et al. in 1978, is a distinct, benign subcutaneous lesion characterized histologically by encapsulated fat necrosis. We report a case of nodular cystic fat necrosis in a 22-year-old man who had had two mobile, rice-sized, deep-seated papules on his right shin for ten years after trauma. Histologically, the excised mass showed encapsulated fat necrosis, calcification, and lipomembranous changes. The encapsulation of necrotic tissue may prevent further extension of adiponecrosis. The subcutaneous fat is prone to trauma or ischemia. The observation of lipomembranous changes in nodular cystic fat necrosis seems to support the concept that lipomembranous change is a nonspecific pattern of the fat necrosis due to multiple local or systemic events causing a compromise in the blood supply of the subcutaneous tissue.