Hyperkeratosis-hyperpigmentation syndrome describes a very rare hyperpigmentation of the skin characterized by tiny hyperpigmented spots mainly on skin exposed to sunlight, together with mild punctate palmoplantar papular hyperkeratosis as a major feature. There have been no further descriptions in the literature since 1993. The disease is Monarch Disease Ontology entry MONDO_0007757 (hyperkeratosis-hyperpigmentation syndrome).