Clinical Reasoning: A Septuagenarian With Painless Ulceration on the Fingertip.

A 78-year-old nondiabetic nonsmoking man presented with a painless nonhealing ulceration on the middle fingertip of the left hand. Similar episodes occurred in the past involving the left middle and index fingers resulting in amputation of the tip of index finger. Diagnosis was deduced by clinical reasoning and confirmed by additional investigations. Readers are presented with a rational step by step diagnostic paradigm in a very rare presentation of a common neurologic disorder.