Hypomelanotic macules

Hypomelanotic macules are otherwise known as ash-leaf spots due to their resemblance to Sorbus aucuparia, or mountain-ash, leaves. These macules have a strong association with tuberous sclerosis and are often multiple and present in the vast majority of individuals with the condition (up to 97% 1). As such the presence of more than three hypomelanotic macules prompts further investigation. 

Pathology

Histologically, melanocytes are distributed normally within the stratum basale of the epidermis but contain a reduced level of melanin 2

Differential diagnosis

Important differentials to consider include:

  • nevus anaemicus: mediated by vasoconstriction
  • achromic nevus: a form of congenital mosaicism, where some melanocytes have a reduced ability to generate melanin
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Article information

rID: 60529
Section: Signs
Synonyms or Alternate Spellings:
  • Ash-leaf spots

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