Achromic naevus, often called as nevus depigmentosus is an uncommon birthmark (naevus) characterized by a well-defined pale patch. Individuals belonging to all races and sex can be affected. It increases in size with the growth of the body reaching its maximum dimensions and usually remains stable throughout life thereafter. Pathophysiology and Causes: It is believed to be due to a functional defect of melanocytes with morphological abnormalities of melanosomes.
It is also said to be a form of cutaneous mosaicism wherein an altered clone of melanocyte has a decreased ability to synthesize melanin and transport to keratinocytes. It may be caused by reduced numbers of melanocytes, reduced melanin production or the inability of melanocytes in the affected area to transfer melanosomes (melanin-containing granules) to keratinocytes (skin cells). Melanosomes are usually normal in size,…
