Stains & CD markers

Last author update: 1 June 2013
Last staff update: 25 June 2021

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PubMed Search: Fontana-Masson

Lauren N. Stuart, M.D., M.B.A.
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Cite this page: Stuart L. Fontana-Masson. website. Accessed February 22nd, 2024.
Definition / general
  • Melanin stain
  • Interpretation: melanin granules reduce ammonia-silver nitrate and turn black, but difficult to interpret faint staining in sparsely positive cells
Clinical features
  • Melanin is normally found in skin, eye, substantia nigra, melanoma
  • Melanin stains are Fontana-Masson (stains melanin black) and Schmorl method (stains melanin blue-green)
  • Bleaching with potassium permanganate or hydrogen peroxide is used to remove melanin to examine cellular morphology
  • Note: pseudomelanin of melanosis coli, usually found in macrophages, is PAS positive; true melanin is not
Microscopic (histologic) images

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Melanotic neuroectodermal tumor of infancy

Positive staining - normal
Positive staining - disease
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Image 01 Image 02