Stains & molecular markers
Fontana-Masson
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Fontana-Masson
Fontana-Masson
Author: Lauren N. Stuart, M.D., M.B.A.
Topic Completed: 1 June 2013
Minor changes: 8 March 2021
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Fontana-Masson
Table of Contents
Definition / general | Clinical features | Microscopic (histologic) images | Positive staining - normal | Positive staining - diseaseCite this page: Stuart L. Fontana-Masson. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsfontana.html. Accessed May 11th, 2021.
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
Images hosted on other servers:
Melanoma
Melanotic neuroectodermal tumor of infancy
Positive staining - normal
- Any cell containing melanin (e.g. melanocyte, Hum Pathol 2012;43:898)
Positive staining - disease
- Any melanin containing cell; also some forms of yeast and yeast-like organisms (Hum Pathol 2012;43:898)
