Cholesterol Crystal Deposition in Basal Cell Carcinoma: An Investigation of 4 Cases

Cholesterol crystals are a primary cause of cholesterol embolism if they appear in vessels. Various papers have reported the involvement of cholesterol crystal deposition in cutaneous diseases such as xanthoma. However, no cases of cholesterol crystal involvement in cutaneous cancer have been reported. We report four cases of basal cell carcinoma with cholesterol crystal deposition, and discuss the mechanism(s) of the condition. Disease duration, anatomical site, histopathological features, and serum lipid profiles were investigated. The median disease duration was 3.5 years, and the sites of the lesions were the scrotum (one patient) and the nose (three patients). Histopathologically, there was necrotized tissue around the clefts. In addition, we detected frequent apoptotic cells around the cholesterol clefts in two of the patients by using the terminal deoxynucleotidyl transferase dUTP nick-end labeling method. Serum lipid levels were slightly elevated in two of the patients. In conclusion, cholesterol crystal deposition in basal cell carcinoma was considered to relate to a long disease duration with a tumor in a region that was subject to external irritation. Histopathologically, apoptotic cells around the cholesterol clefts indicated that lipids from the tumor cell membranes were one of the causes of cholesterol crystal deposition.