Hemochromatosis

Slide 1 · Hemochromatosis

Iron overload: mechanism, morphology and clinical consequences

Pathology lecture

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Explain how hepcidin and ferroportin maintain iron balance.

Compare hereditary and secondary mechanisms of iron overload.

Recognize the organ pathology, clinical syndrome and diagnostic approach.

Explain the rationale and limitations of iron-depleting treatment.

Slide 3 · Hemochromatosis: Defining abnormality

An iron-overload disorder characterized by excessive accumulation of tissue iron.

Hereditary forms primarily involve inappropriate intestinal absorption.

Excess iron progressively injures the liver, pancreas and other organs.

Slide 4 · Two broad pathways to systemic iron overload

Hereditary hemochromatosis

Inherited disturbance of iron regulation

Iron absorption remains inappropriately high

Long presymptomatic accumulation

Secondary hemochromatosis

Repeated transfusion or other acquired burden

Ineffective erythropoiesis can increase absorption

Tissue deposition may also cause organ injury

Slide 5 · Normal and severe total-body iron burdens

2–6 g

Normal adult total-body iron pool

>50 g

Possible iron pool in severe hemochromatosis

Slide 6 · The liver is a major iron reservoir

≈0.5 g

Iron ordinarily stored in the adult liver

>⅓

Of total body iron may accumulate in the liver in severe disease

Slide 7 · Principal tissue targets of iron overload

Liver

Cirrhosis and cancer risk

Pancreas

Islet injury and fibrosis

Heart

Arrhythmia and cardiomyopathy

Endocrine glands

Hypogonadism and hormone loss

Joints

Arthropathy and synovitis

Skin

Characteristic dark pigmentation

Slide 8 · The classic advanced clinical pattern

Micronodular cirrhosis, diabetes and abnormal skin pigmentation characterize fully developed disease.

These findings usually emerge after prolonged iron accumulation.

An individual diagnosed early may have none of the classic manifestations.

Slide 9 · Why hereditary disease often presents late

Long latency

Tissue iron accumulates gradually throughout life.

Progressive injury

Oxidant damage and fibrosis develop slowly.

Clinical syndrome

Symptoms typically emerge after years of accumulation.

Slide 10 · Age and sex patterns reflect cumulative exposure

Textbook pattern: Symptoms commonly begin in the fourth to fifth decades in men.

Menstruation slows net accumulation before menopause in many women.

Presentation and penetrance vary; Genotype is not equivalent to disease.

Slide 11 · Iron excess converts a nutrient into a toxin

Progressive tissue iron

Iron-driven reactive oxygen species

Cell injury and fibrosis

Iron-catalyzed free radical chemistry links iron accumulation to parenchymal injury.

Slide 12 · Three major mechanisms of hepatic injury

Iron-catalyzed lipid peroxidation damages cell membranes.

Hepatic stellate-cell activation promotes collagen deposition.

Iron and reactive oxygen species can injure DNA and favor carcinogenesis.

Slide 13 · Normal control of dietary iron absorption

Dietary iron uptake

Enterocyte iron export

Plasma transferrin iron

The critical regulated gate is ferroportin-mediated iron release to plasma.

Slide 14 · Hepcidin is the central systemic regulator

Hepcidin is a liver-derived peptide encoded by HAMP.

It regulates iron movement into plasma by acting on ferroportin.

Its concentration integrates iron availability, inflammation and erythropoietic demand.

Slide 15 · Hepcidin restricts iron release

Hepcidin binds ferroportin

Ferroportin internalized and degraded

Iron export decreases

The response limits release from enterocytes and iron-recycling macrophages.

Slide 16 · Signals that increase hepcidin synthesis

Increased iron availability stimulates the liver to raise hepcidin.

Inflammatory cytokines also upregulate HAMP transcription.

Reduced ferroportin activity subsequently limits iron entry into plasma.

Slide 17 · Signals that decrease hepcidin synthesis

Iron deficiency lowers HAMP transcription.

Hypoxia reduces hepcidin production.

Erythroferrone from erythroblasts suppresses hepcidin during erythropoietic drive.

Slide 18 · Ferroportin operates at two important sites

Intestinal enterocyte

Exports recently absorbed dietary iron

Hepcidin blocks onward transfer to blood

Macrophage

Releases iron recovered from erythrocytes

Hepcidin favors intracellular retention

Slide 19 · A normal feedback loop protects iron balance

Body iron rises

Liver raises hepcidin

Less intestinal iron enters plasma

Negative feedback normally restrains further iron acquisition.

Slide 20 · Hereditary iron overload breaks this feedback

Defective hepcidin pathway

Hepcidin action insufficient

Iron export and uptake persist

The liver fails to apply the expected brake despite high iron stores.

Slide 21 · HFE participates in hepatic iron sensing

HFE encodes an HLA class I–like protein.

Normal HFE signaling helps stimulate hepatic hepcidin synthesis.

Loss of HFE function permits excessive iron absorption.

Slide 22 · HFE loss of function: Causal chain

HFE dysfunction

Inappropriately low hepcidin

Ferroportin remains active

Systemic iron loading

Slide 23 · Genes linked to hereditary hemochromatosis

Gene / protein

Textbook-associated phenotype

HFE

Most common adult-onset hereditary form

TFR2 (transferrin receptor 2)

Rare hereditary iron overload

HAMP (hepcidin)

Rare juvenile form

HJV (hemojuvelin)

Rare juvenile form

SLC40A1 (ferroportin)

Rare ferroportin-associated form

Slide 24 · Most adult hereditary cases involve HFE

Adult-onset hereditary hemochromatosis is usually HFE-associated.

HFE encodes an upstream component of iron-responsive hepcidin regulation.

Disease develops when iron accumulation ultimately overwhelms tissue tolerance.

Slide 25 · Juvenile forms involve HAMP or HJV

HAMP encodes the circulating inhibitor hepcidin.

HJV encodes hemojuvelin, an upstream regulator of hepcidin synthesis.

Loss-of-function variants in either gene can produce juvenile hemochromatosis.

Slide 26 · Ferroportin has its own genetic category

SLC40A1 encodes the iron-export channel ferroportin.

Rare SLC40A1-associated hereditary hemochromatosis.

Ferroportin disease should not simply be equated with an HFE defect.

Slide 27 · HFE C282Y: The principal textbook variant

C282Y

Cysteine → tyrosine substitution at amino acid 282

≥70%

Proportion of diagnosed hereditary cases attributed to C282Y in the text

Slide 28 · HFE H63D is a second associated variant

H63D denotes histidine → aspartate substitution at amino acid 63.

H63D has a worldwide distribution.

Its disease penetrance is lower than that of C282Y homozygosity.

Slide 29 · The distribution of HFE variants differs

C282Y

Largely confined to populations of European ancestry

Textbook reports about 0.45% homozygosity in European descent

H63D

Worldwide distribution

Homozygosity and C282Y/H63D compound heterozygosity have relatively low penetrance

Slide 30 · Genotype is not synonymous with clinical disease

0.45%

C282Y homozygosity in people of European descent; Textbook estimate

≈10%

C282Y-homozygous men with evidence of overload; Textbook estimate

Slide 31 · Why a pathogenic genotype may remain silent

Inheritance establishes susceptibility, not a fixed trajectory of tissue damage.

Observed penetrance depends on genotype, sex and cumulative iron loading.

Family evaluation should distinguish a risk genotype from existing organ injury.

Slide 32 · A pathologic sequence begins in hepatocytes

Early

Golden-yellow iron granules in periportal hepatocytes.

Increasing load

Deposits spread through more of the hepatic lobule.

Advanced

Additional biliary and Kupffer-cell deposits accompany fibrosis.

Slide 33 · Earliest hepatic iron: Periportal accentuation

Portal tract

Central vein

Schematic — not a histologic specimen

Iron initially predominates in hepatocytes closest to the portal tract.

Slide 34 · Iron deposition extends across the lobule

Portal tract

Central vein

Schematic — not a histologic specimen

The distribution broadens as total hepatic iron loading increases.

Slide 35 · Advanced overload becomes widespread

Portal tract

Central vein

Schematic — not a histologic specimen

Late-stage iron accumulation includes additional cell compartments.

Slide 36 · Prussian blue demonstrates storage iron

Hemosiderin appears as golden-yellow cytoplasmic granules in routine sections.

Perls / Prussian blue reaction makes stainable tissue iron blue.

Staining supports recognition of deposition; Interpretation requires tissue context.

Slide 37 · Iron toxicity need not provoke marked inflammation

Hemochromatosis produces direct hepatocellular toxicity.

Inflammation is characteristically absent or inconspicuous description.

Hepatic fibrosis may develop despite limited inflammatory infiltrates.

Slide 38 · Gross liver changes evolve with time

Early disease

Slightly enlarged liver

Dense parenchyma

Chocolate-brown discoloration

Advanced disease

Fibrous septa and nodular remodeling

Small, shrunken micronodular cirrhotic liver

Dark brown to almost black parenchyma

Slide 39 · Iron overload progresses to micronodular cirrhosis

Hepatocyte iron toxicity

Stellate-cell collagen deposition

Fibrous septa and nodules

Slide 40 · Cirrhosis is a late morphologic consequence

Progressive iron injury can eventually produce bridging fibrous septa.

The architectural endpoint is micronodular cirrhosis.

Early iron deposition and established cirrhosis must not be treated as synonymous.

Slide 41 · Pancreatic iron explains glucose dysregulation

Iron accumulation can produce pancreatic parenchymal atrophy.

Interstitial fibrosis accompanies advanced pancreatic involvement.

Injury to islet cells contributes to diabetes mellitus.

Slide 42 · Cardiac hemosiderosis damages myocardium

The heart may be enlarged and strikingly brown from hemosiderin.

Myocardial iron accumulation can be associated with fibrosis.

Clinical expressions include cardiomyopathy and arrhythmias.

Slide 43 · Endocrine deposition contributes to hypogonadism

Iron may affect the pituitary and other endocrine glands.

Reduced gonadotropins and testosterone may lead to testicular atrophy.

Patients may present with loss of libido, impotence or amenorrhea.

Slide 44 · Skin discoloration is not simply stored iron

Patients can develop a characteristic slate-gray appearance.

Increased epidermal melanin production is a major contributor.

The mechanism stimulating melanin is unresolved.

Slide 45 · Iron-associated arthropathy

Articular iron deposition

Synovial and cartilage injury

Atypical arthritis / pseudogout

Calcium pyrophosphate crystal deposition contributes to disabling joint disease.

Slide 46 · Morphologic findings predict multisystem symptoms

Hepatic fibrosis

Hepatomegaly and cirrhosis

Islet injury

Impaired glycemic control

Myocardial iron

Arrhythmia and failure

Pituitary effects

Sex-hormone deficiency

Synovial disease

Joint pain and pseudogout

Pigment changes

Abnormal skin coloration

Slide 47 · Clinical recognition: Presenting complaints

Patients may report abdominal pain, fatigue or unexplained hepatomegaly.

Others present with diabetes, arthritis, cardiac abnormalities or gonadal symptoms.

No single clinical manifestation is sufficiently specific in isolation.

Slide 48 · The complete late syndrome is not required

Cirrhosis, pigmentation, diabetes and cardiac involvement can coexist late.

Routine biochemical investigations now identify many patients earlier.

Absence of the classic tetrad does not exclude iron overload.

Slide 49 · Liver cancer is a major long-term hazard

Iron-mediated DNA damage and cirrhosis increase hepatocellular carcinoma risk.

A marked elevation (200-fold) versus the general population.

This textbook comparison is not a universal individual risk estimate.

Slide 50 · Why risk may persist after iron removal

Iron-driven DNA injury

Later reduction of iron stores

Residual cancer susceptibility

Removing iron cannot necessarily reverse mutations or established cirrhosis.

Slide 51 · Early detection can precede irreversible damage

Many affected individuals are detected before symptomatic cirrhosis.

Iron-related blood tests trigger further evaluation.

Molecular testing can establish a causative hereditary variant.

Slide 52 · A practical diagnostic reasoning pathway

Suspect iron loading

Evaluate iron indices and genotype

Exclude secondary causes

Assess the extent of organ involvement and fibrosis when indicated; This is a conceptual pathway, not a complete guideline.

Slide 53 · Establish the cause, not only iron deposition

Assess family history and potential inherited susceptibility.

Investigate transfusion burden and ineffective erythropoiesis.

Consider concurrent chronic liver disorders and other acquired causes.

Slide 54 · Liver biopsy now has a more selective role

Genetic testing and imaging reduce the need for routine hepatic iron quantification.

Biopsy may still clarify fibrosis or other hepatic pathology.

Interpret biopsy findings alongside biochemical and clinical evidence.

Slide 55 · Familial identification supports prevention

Relatives of an affected proband may carry a susceptibility genotype.

Family testing identifies at-risk people before symptoms appear.

Interpret genetic findings together with actual measures of iron loading.

Slide 56 · Secondary causes of systemic iron loading

Mechanism / context

Textbook examples

Exogenous iron

Repeated red-cell transfusions; prolonged parenteral loading

Ineffective erythropoiesis

Thalassemia; myelodysplastic syndrome

Other hematologic disorders

Severe chronic hemolytic anemia; marrow failure

Other clinical contexts

Chronic liver disease; alcohol-associated disease; porphyria cutanea tarda

Slide 57 · Ineffective erythropoiesis suppresses hepcidin

Expanded erythroblast activity

Erythroferrone rises

Hepcidin falls

Gut iron uptake rises

Slide 58 · Repeated transfusions provide iron directly

Each transfusion brings erythrocyte iron into the recipient.

Long-term transfusion support can progressively raise tissue iron stores.

The mechanism can coexist with absorption stimulated by ineffective erythropoiesis.

Slide 59 · Cirrhosis itself may worsen iron absorption

Loss of hepatocyte mass can reduce hepatic hepcidin production.

This may allow increased intestinal iron uptake.

Iron deposition in chronic liver disease does not automatically indicate an HFE disorder.

Slide 60 · Inherited versus acquired: Pattern recognition

Hereditary pathway

Heritable defect affecting iron sensing or export

Inappropriate iron absorption over many years

Genotype and family assessment central

Acquired pathway

Transfusions and/or expanded erythropoietic drive

Absorption may rise through erythroferrone

Underlying hematologic/liver disease central

Slide 61 · Phlebotomy reverses the positive iron balance

Blood removal

New erythrocyte production consumes iron

Tissue iron stores decline

Regular venesection is the principal preventive treatment described for adult hereditary disease.

Slide 62 · Treatment is most effective before organ injury

Regular phlebotomy progressively depletes excessive stores.

Timely treatment can prevent development or progression of iron-related disease.

Already-established cirrhosis and cancer susceptibility may not fully reverse.

Slide 63 · Secondary overload requires cause-specific care

Transfusion-dependent patients may not be candidates for routine phlebotomy.

Robbins Chapter 14 describes iron chelation in heavily transfused thalassemia.

Treat the underlying hematologic condition and monitor systemic iron burden.

Slide 64 · Case 1: Early hereditary disease

A 43-year-old man has elevated iron measures during an unrelated investigation. He has no cirrhosis, diabetes or skin pigmentation. Genetic evaluation identifies a relevant HFE variant.

What is the central physiologic defect?

Inadequate hepcidin-mediated inhibition of ferroportin permits iron accumulation.

Slide 65 · Case 2: Transfusion-associated overload

A patient with a severe chronic anemia has received red-cell transfusions for many years and subsequently develops hepatic and cardiac iron deposition.

How does the iron accumulate?

Exogenous transfused erythrocyte iron can cause overload even without an inherited HFE defect.

Slide 66 · Case 3: Joint disease and pigmentation

A middle-aged patient with unexplained diabetes presents with arthropathy and slate-gray skin pigmentation. Hepatic iron deposition is demonstrated.

Which associated tissue changes explain these findings?

Pancreatic islet injury, articular deposition / CPPD disease and increased epidermal melanin.

Slide 67 · Case 4: Persistent cancer risk

A patient treated for hereditary hemochromatosis has much lower iron stores but already had established cirrhosis before venesection began.

Why does ongoing liver risk assessment remain relevant?

Prior DNA injury and established hepatic architecture damage may leave residual HCC susceptibility.

Slide 68 · Five pathology principles to retain

Hereditary hemochromatosis is primarily a disorder of iron regulation.

Low hepcidin activity allows persistent ferroportin-mediated iron export.

Periportal hepatocellular iron precedes diffuse deposition and cirrhosis.

Target-organ injury explains diabetes, cardiomyopathy, endocrine disease and arthropathy.

Early diagnosis and appropriate iron depletion protect organs.

Slide 69 · Textbook references

Primary teaching source

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. (2026). Chapter 18, pp. 771–773; complementary iron regulation in Chapter 14.

Supporting foundational section

Robbins, Cotran & Kumar. Chapter 14: iron metabolism, hepcidin–ferroportin regulation, and secondary iron loading in ineffective erythropoiesis.