Atypical squamous cell carcinoma of the nail bed with phalangeal involvement.

We report an atypical presentation of squamous cell carcinoma (SCC) of the distal phalanx of the left thumb. On physical examination, there was no clinical evidence of a local lesion, but magnetic resonance imaging (MRI) showed multiple intraosseous cavities filled with fluid. A biopsy specimen showed a well-differentiated SCC, which was treated by amputation of the distal phalanx.