An intra-oral comedo?
Colquhoun
A
A
D000152:Acne Vulgaris / Q000473:pathology*; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000473:pathology; D006801:Humans; D008297:Male; D009059:Mouth Diseases / Q000473:pathology*; D009061:Mouth Mucosa / Q000473:pathology; D012627:Sebaceous Glands / Q000473:pathology*; D012859:Sjogren's Syndrome / Q000473:pathology