Pigments, minerals, and cytoplasmic granules

1. Pigments, Minerals, and
Cytoplasmic Granules
Spring 2014
Professor Emsley

2. Pigments
What does the word Pigment means?
Pigment- any of the various coloring agents
deposited, frequently as cytoplasmic
inclusions or granules, in cells and tissues.
- colored, not necessary to stain them with
biologic dyes but special stains may be
necessary to differentiate similarly colored
pigments

3. Classification of Pigments
• 3 broad groups- artifacts, exogenous and
endogenous
• Artifact pigments- produced in tissues during
processing and most commonly from fixation.
Pigments lie on top of tissue and not within the
cell although formalin pigment are sometimes
seen within cell cytoplasm. Formalin pigment
occurs when tissue is fixed in acidic
formaldehyde solutions.

4. Exogenous Pigments
• Exogenous pigments are formed
externally and then taken into the body
through various routes.
• Carbon (anthracotic pigment) is a black
pigment commonly seen in sections from
the lung and associated lymph nodes.
• Tatoo pigments- usually found in skin that
has been tatooed, ocassionally found in
lymph nodes.

5. Endogenous hematogenous
pigments
• Endogenous pigments are formed within the
body. Endogenous piugments are classified as
hematogenous (derived from blood) and
nonhematogenous. Hemaglobin, hemosiderin
and bile pigments are the main hematogenous
pigments Fig. 11.1
• Hemaglobin- conjugated protein found normally
in red blood cells and is responsible for
transporting oxygen from lungs to other parts of
the body. Hb stains vividly with acid ( anionic
dyes) such as eosin.

6. Bile pigment
• What is biliverdin ? Biliverdin is a bile
pigment resulting from the destruction of
red blood cells and further breakdown of
the heme portion of hemaglobin. Biliverdin
is transported to the liver, where it
undergoes reduction to bilirubin. Bilirubin
is not normally deposited in tissue but is
removed from circulation by the liver and
then secreted as a component of bile.

7. Endogenous nonhematogenous
pigment
• Pigments not derived from blood. Divided into nonlipidic
and lipidic pigments.
• Nonlipidic – Melanin – amixture of substances closely
bound to proteins, is the most important of the
endogenous nonhematogenous pigments. Melanin is
derived from tyrosine or tyrosine containing compounds
and is characteristically a brown-black pigment present
normally in the hair, skin, retina, iris, and certain parts of
the central nervous system.
• Melanin can be demonstrated in tissue. It can be
bleached, is dissolved by strong alkali but is insoluble in
weak acids and bases or in organic solvents. It is
strongly basophilic, reduces silver nitrate to metallic
silver (argentaffin) and gives a positive Schmorl reaction.

8. Lipidic pigments
• What is lipidic pigment? Lipofuchsin,
commonly referred to as “ wear and tear”
pigment collects in the more permanent
cells ( heart, liver, and neurons) of older
persons. This is a yellow- brown pigment
that stains with Oil Red O, Sudan black B
and the PAS reaction.

9. Minerals
• What are minerals? Minerals are metallic and
nonmetallic ions necessary for growth and other
bodily functions.
• Some of the ions that can be demonstrated with
special stains in tissue are Ca++, Fe ++, Cu ++,
Ag, Pb, Au among others. The Prussian Blue
technique is used to demonstrate iron in tissues.
See page 256 in your text for the Prussian blue
Technique. Please write for Home Work and
bring to class on 11/5/13

10. Cytoplasmic Granules
• Adrenal chromaffin cells, pancreatic endocrine cells,
gastrointestinal enterochromaffin cells, “C” cells of the
thyroid, and some pituitary cells are neuroendocrine cells
that have been shown to possess some common
metabolic processes related to hormone synthesis.
• These cells have a high uptake of amine precursors and
the ability to decarboxylate , hence the name amine
precursor uptake and decarboxylation (AUPD) cells.
• These cells are demonstrated through the argyrophil
and/ or argentaffin reactions.

11. Introduction
• Argyrophil cells have the ability to be impregnated with
silver , but they do not have the ability to reduce the
silver to a visible metallic form; an external reducing
agent ( light or chemical) must be applied.
• Argentaffin cells have both the ability to be impregnated
with silver and to reduce the silver.
• Argentaffin cells also will give a positive reaction with
argyrophil techniques, but argyrophil cells will not give a
positive reaction with argentaffin techniques.
• Chromaffin granules- adrenal medulla (CAM)
• Argentaffin granules- intestinal mucosa (AIM)

12. PRUSSIAN BLUE TECHNIQUE for Ferric
Iron
• Purpose- To detect ferric iron in tissues.
• Ferric iron is normally found in small amounts in the bone marrow
and the spleen. Excess iron has no specific mechanism through
which it can be excreted form the body but it can only br lost by
bleeding or hemorrhage, menstrual flow, sloughing of cells and
transfer to a fetus.
• Too much iron storage is termed iodiopathic hemochromatosis.
Excess iron storage is termed hemosiderin, ( liver and spleen, but
also can be found in heart, muscle, and nerve .
• What is the principle behind the Prussian Blue technique?

13. Fontana Masson Technique for Melanin and
Argentaffin Granules
• Principle:- certain tissue components are argentaffin; that is, they
possess the ability to bind silver from a solution and to reduce it to
visible metallic silver without the need for a separate reducing
agent.
• 10% neutral buffered formalin can be used as a fixative. Avoid
alcohol because it dissolves argentaffin granules.
• Quality control- skin for melanin and small intestine or appendix for
argentaffin.
Tumor Cell From
Small Intestine
Melanin From the Skin

14. Grimelius stain
• Principle:- certain tissue components have the ability to bind silver
ions from solution but no inherent ability to reduce the silver to its
visible metallic form. An external or chemical reducer is used for this
purpose.
• 10% neutral buffered formalin can be used as fixative.
• Quality control: an argyrophil- positive carcinoid tumor is preferred,
but a section of small intestine can be used.
Argyrophil Cells of
Carcinoid Tumor
from small intestine

15. Components of Orth’s Solution
• Chromaffin granules are best preserved
with the use of Orth’s solution
• Potassium dichromate 2.5 grams
• Sodium sulfate 1.0 gram
• Distilled Water 100 ml
• Just before use add
• Formaldehyde, 37% to 40% 10ml