Hyperpigmented lesion returns to the palm

A woman aged 37 years presented with an asymptomatic, ill-defined patch on the palm. The hyperpigmented, bluish-gray lesion had flared on and off for the past few years.

Occasionally, the patch would fade considerably, only to darken several times a year, never quite disappearing completely. Two potential triggers emerged on history-taking: (1) an OTC aspirin- and caffeine-containing analgesic; and (2) ...