Ungual seborrheic keratosis.

BACKGROUND/OBJECTIVES: Seborrheic keratoses are ubiquitous benign epithelial skin tumours. A number of unusual locations have already been reported. We report herein the case of a seborrheic keratosis of the nail bed with typical histological features.

METHODS/RESULTS: A 58-year-old man presented with a 1-year-history of longitudinal leukoxanthonychia of the right hallux. Surgical treatment was performed. The diagnosis of typical seborrheic keratosis of the nail bed was made on histological examination.

CONCLUSION

To our knowledge, this is the first report of a typical, histologically documented seborrheic keratosis of the nail bed. Therefore, this condition should be added to the differential diagnosis of acquired longitudinal leukoxanthonychia. However, surgical treatment remains necessary to rule out other causes, including squamous cell carcinoma.