week 9 calcification & pigmentation.pdf

8/10/2019 WEEK 9 Calcification & pigmentation.pdf

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Calcification &Pigment

AccumulationPresented

ByAhmed El-Rashedy

Professor & Previous Headof Pathology DepartmentAl-Azhar University


3/17

Pathologic Calcification

Def.:

Deposition of calcium salts (ca phosphate & ca carbonate) in soft

tissues probably leading to malfunction.

Normally, precipitates of calcium salts are found only in

bones, otoliths and teeth.

Pathological calcification may be radiologically evident and

diagnostically useful.Types:

1. Metastatic calcification.

2. Dystrophic calcification.

Calcinosis Cutis:A calcification of the skin & subcutaneous (S.C.) tissue.

Calcinosis Universalis:

A widespread calcification of the muscles and tendons as well as

that of the skin & S.C. tissue.

Prof. Dr. Ahmed Elrashedy


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Differences Between Metastatic & Dystrophic Calcification

DystrophicMetastatic

Normal (9-11 gm%)(>11gm%)1.Serum

ca++ level:

Deposition of calcium salts in:1. Previously damaged tissues:

as thrombus, infarcted area,atheromatous plaques,congenitally bicuspid aorticvalve, calcified mitral valvering, old caseous tubercle,

bilharzial ova, old scars, fatnecrosis, breast lesions,

calcinosis cutis.2. Necrotic tumors: eitherA) Benign: Fibromyoma,

meningioma, thyroid adenoma.B) Malignant: mammary duct

carcinoma & carcinosarcoma.

calciumabsorption from GIT: inhypervitaminosis D. calcium mobiliz-ation from the bones asin case of :1. Hyperparathyroidism.2. Chronic renal failure.3. Osteolytic bone

metastasis.

2. Causes:



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DystrophicMetastatic

No Harmful Effects onthe functions.

An exception is:

Calcified congenitally

bicuspid aortic valve. Abicuspid aortic valve can

function quite normally

but when it becomes

calcified, the valve cusps

become thick and rigid.

This causes finally heart

failure.

1. Nephrocalcinosis: withimpaired renal function.

2. Calcification of the

GIT mucosa:with

defective absorption &digestion.

3. Calcification of the

alveolar walls:with

lack of oxygenation.

4. Calcifications of

arterial media:with

loss of its elastic recoil.

3. Effects:

Differences Between Metastatic & Dystrophic Calcification



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N.B.:1. Metastatic calcification must not be confused with

the process of metastasis of tumours.

2. Metastatic

calcification means being widespreadwhile dystrophic means occurring in a tissue alreadyaffected by disease.

Diagnosis:

1) Cl inical ly: At surgery, calcification is felt extremely hard.

2) Biochemically: Dystrophic calcification in case of fat

necrosis (due to trauma to adipose tissue or acute

pancreatitis), the liberated fatty acids bind calcium to form

insoluble calcium soaps, sometimes causing hypocalcaemia

and tetany.

3) Radiologically: The calcified lesions will often appear on

plain X-ray as opacities (white shadows).



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Diagnosis:

4. Pathologically:

A) Dystrophic calcification:

a) In some breast carcinomas as one of the abnormalities

detected in the mammography (breast X-rays) done for breast

cancer

(microcalcifications).

b) Some tumours contain minute concentric lamellated calcifiedbodies called psammoma bodies (psammos in Greek means

sand). These tumors are :

1. Meningiomas.

2. Papillary carcinomas of thyroid.

3. Papillary ovarian carcinomas.

Significance: Psammoma bodies help the histopathologist in

the correct diagnosis of the type of tumour.


P f D Ah d El h d


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B) Metastatic calcification (In hypercalcemia):

I. In alveolar walls:Appears as a purple-staining material deposited on

alveolar walls.

II. Widespreadcalcification:Occurs in normal tissues.Common causes of metastatic calcification :

1) Hyperparathyroidism due to adenoma or diffuse hyperplasia of the

parathyroid glands.

2) Hypercalcemia of malignancy. In adenoma or diffuse hyperplasia of the parathyroid glands: There

is a secretion of an excess parathyroid hormone which releases

calcium from the bone leading to hypercalcemia.

In some malignant neoplasms, hypercalcemia results from either thesecretion of a parathyroid hormone-like substance or extensive bone

erosion due to skeletal metastases. In this condition the calcium salts

are precipitated on to connective tissue fibres (e.g. collagen & elastic

fibers).



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Intracellular Pigment Accumulation

Pigment accumulated inside the cells may come into the body from

the external environment (exogenous) or synthesized within the

body itself (endogenous).

I) Exogenous pigmentation

Def.: Abnormal accumulation of pigment coming to the body

from outside.

Types of exogenous pigments:

1) Carbon or coal dust (Anthracosis).

2) Inoculated pigment (Tattooing).

1)Anthracosis

Inhalation and trapping of carbon or coal dust within the alveolar

macrophages that will transport it into the draining

tracheobronchial LNs through intervening lymphatics black

discoloration of the lung tissues & the involved L.Ns.



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1) Anthracosis

Examples:

1. Coal miners.2. Those living in a heavily air polluted environment.

Complications:

1. Pulmonary fibrosis.

2. Emphysema.

3. Pulmonary hypertension followed by right sided heart

failure (Cor-pulmonale ).

2) Tattooing

Def.: A localized cutaneous exogenous pigmentation with

trapping of the inoculated pigment within the dermal

macrophages and remains for life.



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II) Endogenous Pigmentation

Def.:Abnormal accumulation inside the tissue cells of

pigment synthesized within the body itself.

Types of endogenous pigments:

1. Lipofuscin (Lipochrome; Ageing pigment).

2. Melanin.3. Hemosiderin.

4. Bilirubin.


P f D Ah d El h d


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BilirubinHemosiderinMelaninLipofuscin

Hb-derived

pigment

Hb-derived pigment

(Small aggregates of

ferritin molecules)

Oxidation of

tyrosine into

dihydroxy-

phenyl

alanine

Lipid peroxid-

ation of poly-

unsaturated

lipids of the

cell &

subcellular

membranes.

1. Origin:

Normal major

pigment in thebile.

Iron conjugated with

apoferritin protein.

Amino acid.Lipid

polymers +phospholipids

complexed

with proteins.

2. Chemical

nature:

1. Liver :

(bile sinusoids,kupffer phagocytic

cells& hepatocytes

2. Kidney: renal

tubular

epithelium.

A) Localized: Inside

the macrophages.B) Systemic:

Many organs &

tissues (liver, spleen,

kidney, LNs, B.m.,

pancreas, endocrine

glands ).

Melanocytes

&melanophors

of the skin

Liver cells +

cardiacmuscles

(cytoplasmic)

3. Sites:


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Hyperbilirubinemia due to :

1. Biliary Obstruction.

2. Hemolysis.

3. Liver cell failure

Hemorrhage or

hemolysis.

iron absor-

ption fromdiet.

iron utili-

zation

Prolonged

exposure

to sunlight

Ageing

process

4. Cause:

1) Obstructive jaundice:

a) Cancer head of pancreas.b) Cholangiocarcinoma: of

common bile duct.

2) Hemolytic jaundice: in all

hemolytic anemias.

3) Hepatocellular jaundice:

a) Hepatitis.b) Liver cirrhosis.

c) Hepatocellular tumors.

A) Localized:

1) Contusion(Bruise).

2) Local Hge.

B) Systemic:

1) Hemolytic

anemias.

2) Hemolytic3) blood

transfusion.

Prolonged

exposureto sunlight

1) Brown

atrophy ofheart

2) Severe

malnutrition

3) Cancer

cachexia

5. Examples

Orange-red.

N.B.: Bile itself is green

brown - to - black

Golden yellow-

brown

Brown-

black

Yellow-

brown

6. Color:



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1) Pigment gall

stones.

2) Pigmentary

livercirrhosis.

3) Kernicterus

particularly

in neonates

with brain

atrophy.

1.Localized:

Noharmful effects.

2. Systemic:

Anemia. Impaired functions of the

involved organs.

N.B.:

1) At first , the pigment will be

found inside the phagocytic

cells ,then, theparenchymal cells become

pigmented.

2) Prussian blue reaction:

This differentiates between

lipofuscin & hemosiderin. If

the color is changed from

yellow-brown into blue, this

is hemosiderin (+ve

reaction). Lipofuscin color

doesnt change (-ve

reaction).

Hyperpig-

mentation.

Shrinkage

of involved

organ

withoutharmful

effects on

its cells or

function.

7. Effects:

Pro

f.Dr.Ahmed

Elrashedy

P f D Ah d El h d


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1) Anthracosis 2) Tattooing

I. Exogenous Pigmentation


Prof Dr Ahmed Elrashedy


16/17

1) Brown atrophy of the heart (right)

versus cardiac hypertrophy (left) 2)Melanin pigment

3) Hemosiderosis in

spleen & liver

4) Jaundice (left) & bilirubin (right)in small bile ductules in the liver

II. Endogenous Pigmentation



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