FDG PET/CT appearance of benign pilomatricoma

A 56-year-old patient was referred for FDG PET/CT with a right preauricular lymph node fine-needle biopsy, suggesting poorly differentiated carcinoma and no obvious primary lesion. There was intense FDG uptake in the right preauricular nodule. The node was excised, and formal histology demonstrated a benign pilomatricoma rather than malignancy. Pilomatricoma is uncommon in adults and an unusual cause for marked FDG uptake, likely due to foreign body inflammation. Pilomatricoma can be either benign or malignant. The marked FDG uptake demonstrated in our patient with benign pilomatricoma also suggests that FDG PET cannot reliably grade this rare condition.