Subungual Keratoacanthoma: Typical and Atypical Presentations of an Uncommon Nail Tumor.

Introduction: Keratoacanthoma (KA) is a group of tumors of epidermal origin with controversial nature. Subungual keratoacanthoma (SUKA) is a rare and destructive variant with more aggressive behavior. SUKA appears as a rapidly growing, painful tumor beneath the nail plate that rapidly progresses to a mass that can measure up to 2 cm. The toe location is unusual. The diagnosis must be made based on the correlation of clinical, radiological, and histopathological findings.

Case presentation: We present two cases of patients diagnosed with SUKAs with different clinical presentations which ranged from very typical to uncommon one. Both cases were treated with simple excision without recurrences.

Conclusion: SUKA is a rare subungual tumor. Nail bed location represents a more difficult diagnostic challenge. SUKA should be suspected in the context of persistent and progressive pain on a finger or toe, once more frequent painful tumors have been ruled out.