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Malignant Tumours | Tumours of Blood Vessels | Blood Vessels and Heart | Special Pathology (Special Patho) | 4th Year (Fourth Year) | MBBS | Detailed Free Notes

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1. Core Concept: Malignant Vascular Tumours

Malignant tumours of blood vessels are aggressive neoplasms derived from endothelial cells with a strong tendency for:

  • Local tissue destruction

  • Early hematogenous spread

  • Poor prognosis

Exam anchor line:
Malignant vascular tumours are aggressive endothelial neoplasms characterized by infiltrative growth and early metastasis.

2. Classification of Malignant Vascular Tumours (MBBS-Relevant)

Malignant tumours of blood vessels include:

  1. Angiosarcoma (most important, must-know)

  2. Hemangioendothelioma (intermediate-grade, borderline)

  3. Kaposi sarcoma (often discussed separately under immunodeficiency)

👉 For MBBS pathology, ANGIOSARCOMA is the core examinable malignant tumour.

3. Angiosarcoma — Overview (Most Important Section)

3.1 Definition

  • Angiosarcoma is a:

    • Highly malignant tumour

    • Arising from vascular endothelial cells

  • Characterized by:

    • Irregular, anastomosing vascular channels

    • Marked cellular atypia

3.2 Epidemiology

  • Rare tumour

  • Occurs mainly in:

    • Adults

    • Elderly individuals

  • Slight male predominance

  • Associated with specific risk factors (discussed later)

4. Common Sites of Angiosarcoma (Very High-Yield)

Angiosarcoma can arise anywhere, but shows predilection for certain organs.

4.1 Skin and Soft Tissue (Most Common)

  • Head and neck region (especially scalp and face)

  • Common in elderly males

  • Often begins as:

    • Bruise-like lesion

    • Purplish patch

4.2 Liver (Classical Association)

  • One of the most feared visceral angiosarcomas

  • Strongly associated with:

    • Chemical carcinogens

4.3 Breast

  • May arise:

    • De novo

    • After radiotherapy (post-mastectomy)

4.4 Other Sites

  • Spleen

  • Bone

  • Heart

  • Deep soft tissues

5. Etiology and Risk Factors of Angiosarcoma (Exam-Favourite)

5.1 Chemical Exposure (Classic Question)

Angiosarcoma of the liver is associated with:

  • Vinyl chloride

  • Arsenic

  • Thorium dioxide (Thorotrast)

Exam line:
Vinyl chloride exposure is classically associated with hepatic angiosarcoma.

5.2 Chronic Lymphedema (Stewart–Treves Syndrome)

  • Angiosarcoma arising in:

    • Chronically lymphedematous limbs

  • Classically seen after:

    • Radical mastectomy with lymph node dissection

5.3 Radiation Exposure

  • Post-radiation angiosarcoma

  • Seen in:

    • Breast

    • Skin

  • Long latent period

5.4 Sporadic Cases

  • Occur without identifiable cause

  • Particularly in:

    • Skin of elderly

6. Pathogenesis of Angiosarcoma (Step-wise)

6.1 Endothelial Cell Transformation

  • Genetic damage to endothelial cells leads to:

    • Loss of growth control

    • Unregulated angiogenesis

6.2 Abnormal Angiogenesis

  • Formation of:

    • Irregular

    • Poorly formed vascular channels

  • Tumour cells invade:

    • Surrounding tissues

    • Vascular spaces

6.3 Aggressive Biological Behavior

  • High mitotic rate

  • Infiltrative margins

  • Early blood-borne metastasis

7. Gross Morphology of Angiosarcoma

7.1 External Appearance

  • Ill-defined mass

  • Poorly circumscribed

  • Hemorrhagic areas common

7.2 Cut Surface

  • Spongy, blood-filled areas

  • Necrosis and hemorrhage

  • Infiltrative margins

8. Microscopic Features (Extremely High-Yield)

8.1 Vascular Pattern

  • Irregular, anastomosing vascular channels

  • Channels dissect through connective tissue

8.2 Cellular Features

  • Endothelial cells show:

    • Pleomorphism

    • Hyperchromatic nuclei

    • Increased mitotic activity

8.3 Solid Areas

  • Poorly differentiated tumours may show:

    • Solid sheets of malignant cells

    • Minimal recognizable vascular formation

8.4 Immunohistochemistry (Add-On for Completeness)

Tumour cells express:

  • CD31

  • CD34

  • Factor VIII–related antigen

9. Clinical Features of Angiosarcoma (Introductory)

9.1 Skin Angiosarcoma

  • Painless bruise-like lesion

  • Rapid enlargement

  • Ulceration and bleeding

9.2 Visceral Angiosarcoma

  • Liver:

    • Hepatomegaly

    • Abdominal pain

    • Jaundice

  • Often advanced at diagnosis

10. PART 1 CONSOLIDATED TAKEAWAY

  • Angiosarcoma is the most important malignant vascular tumour

  • Derived from endothelial cells

  • Highly aggressive with poor prognosis

  • Commonly affects skin, liver and breast

  • Associated with vinyl chloride, radiation and chronic lymphedema

  • Histology shows malignant endothelial cells forming irregular vascular channels

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Special Pathology Free Material

11. Clinical Features of Angiosarcoma (General Overview)

The clinical presentation of angiosarcoma depends on:

  • Site of origin

  • Depth of tumour

  • Degree of differentiation

  • Rate of growth

Exam anchor line:
Angiosarcomas present as rapidly enlarging, infiltrative, hemorrhagic tumours with early metastatic potential.

12. Cutaneous Angiosarcoma (Most Common Presentation)

12.1 Epidemiology & Site Preference

  • Typically affects:

    • Elderly patients

    • More common in males

  • Predominantly involves:

    • Scalp

    • Face

    • Forehead

12.2 Early Clinical Appearance (Deceptive Stage)

  • Begins as:

    • Ill-defined bruise-like area

    • Purplish or reddish patch

  • Often mistaken for:

    • Hematoma

    • Benign vascular lesion

    • Inflammatory condition

12.3 Progressive Features

  • Rapid increase in size

  • Formation of:

    • Nodules

    • Plaques

  • Skin becomes:

    • Indurated

    • Ulcerated

  • Frequent bleeding on minor trauma

12.4 Advanced Cutaneous Disease

  • Extensive infiltration of surrounding skin

  • Satellite nodules

  • Poorly defined margins

  • High recurrence rate after excision

13. Angiosarcoma Associated with Chronic Lymphedema

(Stewart–Treves Syndrome)

13.1 Definition

  • Angiosarcoma arising in:

    • Chronically lymphedematous tissue

  • Classically after:

    • Radical mastectomy with axillary node dissection

13.2 Pathogenesis

  • Chronic lymph stasis leads to:

    • Local immune dysfunction

    • Chronic inflammation

    • Endothelial proliferation

13.3 Clinical Features

  • Occurs years after surgery

  • Appears as:

    • Multiple purplish nodules

    • Bruise-like lesions on swollen limb

  • Extremely aggressive

  • Very poor prognosis

14. Hepatic Angiosarcoma (Classic Toxic Association)

14.1 Epidemiology

  • Rare but highly lethal

  • Strongly associated with:

    • Vinyl chloride exposure

    • Arsenic

    • Thorotrast

14.2 Clinical Presentation

  • Hepatomegaly

  • Right upper quadrant pain

  • Weight loss

  • Jaundice

  • Ascites (late)

14.3 Complications

  • Hepatic failure

  • Intra-abdominal hemorrhage

  • Early metastasis

14.4 Diagnostic Difficulty

  • Often diagnosed late

  • Imaging may mimic:

    • Hepatocellular carcinoma

    • Metastatic disease

15. Breast Angiosarcoma

15.1 Types

  1. Primary breast angiosarcoma

  2. Secondary (radiation-induced) angiosarcoma

15.2 Radiation-Induced Angiosarcoma (High-Yield)

  • Occurs years after:

    • Radiotherapy for breast carcinoma

  • Arises in:

    • Skin and subcutaneous tissue of irradiated breast

15.3 Clinical Features

  • Violaceous skin discoloration

  • Nodular or plaque-like lesion

  • Rapid progression

  • Frequent local recurrence

16. Cardiac Angiosarcoma (Rare but Exam-Notable)

16.1 Site Preference

  • Right atrium (most common)

16.2 Clinical Features

  • Chest pain

  • Dyspnea

  • Pericardial effusion

  • Cardiac tamponade (late)

16.3 Prognosis

  • Extremely poor

  • Often fatal within months

17. Bone and Soft Tissue Angiosarcoma

17.1 Presentation

  • Painful swelling

  • Pathological fractures (bone)

  • Rapid enlargement

17.2 Behavior

  • Aggressive infiltration

  • Early hematogenous spread

18. Patterns of Spread (Very High-Yield)

18.1 Local Invasion

  • Infiltrates:

    • Surrounding soft tissue

    • Skin

    • Adjacent organs

  • Poorly defined margins

18.2 Hematogenous Metastasis (Most Common)

  • Tumour spreads early via blood

  • Common metastatic sites:

    • Lungs (most common)

    • Liver

    • Bone

    • Brain

18.3 Lymphatic Spread

  • Less common

  • Seen in:

    • Cutaneous lesions

19. Prognostic Factors in Angiosarcoma

19.1 Poor Prognostic Indicators

  • Large tumour size

  • Deep-seated tumours

  • Poor differentiation

  • High mitotic index

  • Presence of metastasis at diagnosis

19.2 Survival Outlook

  • Overall prognosis:

    • Poor

  • 5-year survival:

    • Very low

  • Early diagnosis is rare

20. Comparison: Benign vs Malignant Vascular Tumours

Feature Benign (Hemangioma) Malignant (Angiosarcoma)
Growth Slow Rapid
Margins Well-circumscribed Infiltrative
Endothelial cells Normal Atypical
Mitoses Absent Frequent
Metastasis Absent Common

21. PART 2 CONSOLIDATED TAKEAWAY

  • Angiosarcoma presents with rapidly enlarging hemorrhagic lesions

  • Skin of head and neck is the most common site

  • Strong associations with:

    • Vinyl chloride

    • Radiation

    • Chronic lymphedema

  • Early hematogenous metastasis is characteristic

  • Prognosis is poor due to late diagnosis

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Special Pathology Free Material

22. Kaposi Sarcoma (KS) — Unique Malignant Vascular Neoplasm

22.1 Definition

  • Kaposi sarcoma is a low- to intermediate-grade malignant vascular tumour characterized by:

    • Proliferation of spindle-shaped endothelial cells

    • Formation of slit-like vascular spaces

  • Strongly associated with Human Herpesvirus-8 (HHV-8).

Exam anchor line:
Kaposi sarcoma is a vascular neoplasm associated with HHV-8 infection, commonly seen in immunocompromised individuals.

22.2 Epidemiological Forms of Kaposi Sarcoma (Very High-Yield)

Kaposi sarcoma occurs in four distinct clinical settings:

22.2.1 Classic (Mediterranean) Kaposi Sarcoma

  • Occurs in:

    • Elderly men

    • Mediterranean and Eastern European descent

  • Indolent course

  • Primarily involves:

    • Skin of lower limbs

22.2.2 Endemic (African) Kaposi Sarcoma

  • Seen in:

    • Young adults and children in Africa

  • More aggressive than classic form

  • Lymph node involvement common

22.2.3 Iatrogenic (Transplant-Associated) Kaposi Sarcoma

  • Occurs in:

    • Organ transplant recipients

    • Patients on immunosuppressive therapy

  • May regress if:

    • Immunosuppression is reduced

22.2.4 AIDS-Associated Kaposi Sarcoma (Most Aggressive)

  • Occurs in:

    • HIV-infected patients

  • Widespread disease:

    • Skin

    • Mucosa

    • Lymph nodes

    • Viscera (GI tract, lungs)

  • Most aggressive variant

22.3 Etiopathogenesis of Kaposi Sarcoma

22.3.1 Role of HHV-8

  • HHV-8 infects:

    • Endothelial cells

  • Viral genes promote:

    • Angiogenesis

    • Cell proliferation

    • Resistance to apoptosis

22.3.2 Role of Immunosuppression

  • Reduced immune surveillance allows:

    • Viral-driven endothelial proliferation

  • Explains association with:

    • AIDS

    • Transplant patients

22.4 Gross Morphology

  • Lesions appear as:

    • Red

    • Purple

    • Brown nodules or plaques

  • May coalesce to form large masses

  • Frequently hemorrhagic

22.5 Microscopic Features (Slide-Based Favourite)

22.5.1 Early Lesions (Patch Stage)

  • Irregular, thin-walled vascular spaces

  • Minimal spindle cell proliferation

22.5.2 Plaque Stage

  • Increased spindle cells

  • Slit-like vascular spaces

  • Extravasated RBCs

  • Hemosiderin deposition

22.5.3 Nodular Stage

  • Dense sheets of spindle cells

  • Numerous vascular slits

  • Mitotic figures may be present

22.6 Clinical Features of Kaposi Sarcoma

  • Cutaneous lesions:

    • Painless

    • Non-blanching

  • Mucosal involvement:

    • Oral cavity common in AIDS

  • Visceral involvement:

    • GI bleeding

    • Pulmonary hemorrhage

22.7 Prognosis

  • Depends on:

    • Immune status

    • Extent of disease

  • Best prognosis:

    • Classic form

  • Worst prognosis:

    • AIDS-associated form

23. Hemangioendothelioma — Borderline / Intermediate Vascular Tumour

23.1 Definition

  • Hemangioendothelioma represents a group of vascular tumours with:

    • Biological behavior between hemangioma and angiosarcoma

  • Considered borderline malignant.

23.2 Types (Exam-Relevant)

  • Epithelioid hemangioendothelioma (most important)

  • Spindle cell hemangioendothelioma

23.3 Epithelioid Hemangioendothelioma (EHE)

23.3.1 Definition

  • Tumour composed of:

    • Epithelioid endothelial cells

  • Arranged in:

    • Cords

    • Nests

  • Embedded in myxoid or hyaline stroma

23.3.2 Common Sites

  • Liver

  • Lung

  • Bone

  • Soft tissue

23.3.3 Microscopy

  • Rounded endothelial cells

  • Intravascular lumina may be seen

  • Mild to moderate atypia

  • Mitotic activity:

    • Low compared to angiosarcoma

23.3.4 Clinical Behaviour

  • Locally aggressive

  • Metastasis possible but less frequent

  • Prognosis better than angiosarcoma

24. Differential Diagnosis of Malignant Vascular Tumours (Viva-Critical)

Entity Key Distinguishing Feature
Hemangioma No atypia, no mitoses
Angiosarcoma Marked atypia, infiltrative growth
Kaposi sarcoma HHV-8 association, spindle cells
Hemangioendothelioma Intermediate behavior
AV malformation Congenital, no neoplastic proliferation

25. OSCE — Histopathology & Clinical Stations

OSCE 1: Slide with spindle cells and vascular slits

  • Diagnosis: Kaposi sarcoma

  • Key clue: Slit-like spaces + hemosiderin

OSCE 2: Aggressive hemorrhagic skin tumour in elderly

  • Diagnosis: Angiosarcoma

  • Key clue: Malignant endothelial atypia

OSCE 3: Liver tumour with epithelioid endothelial cells

  • Diagnosis: Epithelioid hemangioendothelioma

26. Viva Voce — High-Yield Questions

Q1. Most aggressive malignant vascular tumour?
A. Angiosarcoma.

Q2. Virus associated with Kaposi sarcoma?
A. HHV-8.

Q3. Classical occupational carcinogen for hepatic angiosarcoma?
A. Vinyl chloride.

Q4. Tumour arising in chronic lymphedema?
A. Angiosarcoma (Stewart–Treves syndrome).

Q5. Behaviour of hemangioendothelioma?
A. Borderline / intermediate malignancy.

27. Examiner Traps (PART 3)

  • Calling Kaposi sarcoma a benign tumour

  • Forgetting HHV-8 association

  • Mixing hemangioendothelioma with hemangioma

  • Missing radiation-induced angiosarcoma

  • Underestimating metastatic potential

28. FINAL CONSOLIDATED TAKEAWAY — MALIGNANT VASCULAR TUMOURS

  • Angiosarcoma is the most important malignant vascular tumour

  • Kaposi sarcoma is HHV-8 driven and immunosuppression-related

  • Hemangioendothelioma shows intermediate behavior

  • Malignant vascular tumours metastasize early

  • Prognosis is generally poor

  • Correct classification is crucial for management and exams

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Special Pathology Free Material

Hunain Zia

Hunain Zia has previously achieved considerable success in the high-school educational stream, gaining a massive 154 Total A Grades and 7 Major Distinctions, a process in which he broke/ set 11 different world records, including the most A grades ever achieved, most subjects ever appeared in, most distinctions, gaining distinctions across two separate boards (Pearson Edexcel and CAIE) within the same year/ ever, and even 19 hours of constant examination. All records stand intact today. Hunain pursued his Honors Accounting Degree from the prestigious Bentley University, and then completed an LLB (in Honors) from University of London. Currently, he manages multiple social and commercial projects, has founded digital streams and works tirelessly in the education sector.

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