Conjunctival melanosis

The term melanosis refers to brown discolouration of the conjunctiva, as a result of an increased amount of melanin pigment. Such increased pigmentation can occur because of:

  • melanin overproduction by a normal population of melanocytes (i.e., melanin-producing cells)
  • excessive proliferation of melanocytes, which can be benign or malignant

Melanosis developing after birth and not caused by a generalised disease is referred to as 'primary acquired melanosis (PAM)'.


Benign and malignant PAM are conventionally referred to as 'PAM without atypia' and 'PAM with atypia' respectively. More precise terms for these conditions are 'C-MIN without atypia' and 'C-MIN with atypia', the acronym referring to conjunctival melanocytic intra-epithelial neoplasia.