Answer to Image of the Month March 2015
Submitted by Rajalakshmi T
Macromelanosomes
Macromelanosomes are giant granules of melanin within melanocytes, which may be spherical or ellipsoid in shape. Ultrastructurally, they have different subytpes implying that there may be a sequence in the development of these structures. They can be transferred to keratinocytes following development.
Macromelanosomes are seen in a variety of conditions such as X-linked ocular albinism, cafe au lait macules of neurofibromatosis, pigmented macules of xeroderma pigmentosum and McCune Albright syndrome. They can also be seen in the skin/eyes of carriers of these genetic conditions. They are also seen in lentigines and there have been reports suggesting that macromelanosomes occur more frequently at the margins of lentigo maligna/melanoma in situ, in contrast to lesions of solar lentigo.