Blood and lymphatic vessel tumours
How tumours of blood and lymphatic vessels range from benign haemangiomas and pyogenic granuloma, through Kaposi sarcoma driven by HHV-8, to angiosarcoma after sun, radiation or lymphoedema, and how they bleed, trap platelets and spread.
By the end, you can
- Describe the structure of capillaries, small vessels and lymphatics, and distinguish a vascular tumour from a vascular malformation.
- Describe the appearance of capillary and cavernous haemangiomas, pyogenic granuloma and lymphangioma.
- Explain how human herpesvirus 8 and weakened immunity together drive Kaposi sarcoma, and name its four clinical forms.
- Contrast angiosarcoma with a haemangioma in appearance and behaviour, and relate it to sun damage, radiation and chronic lymphoedema.
- Explain how vascular tumours cause bleeding and platelet consumption, and how they are graded and staged.
- Recognise the classic microscopic features, markers and tests of vascular tumours, and explain how beta-blockers, mTOR inhibitors, restored immunity, surgery, radiotherapy and chemotherapy act on each.
What it is
A vascular tumour is a neoplasm whose cells show endothelial differentiation, forming channels that copy capillaries, veins or lymphatics. It differs from a vascular malformation, an error in how vessels formed, which grows with the body rather than by cell proliferation. Vascular tumours range from benign (haemangiomas) through intermediate (Kaposi sarcoma) to malignant (angiosarcoma).
3 types to tell apart
- Benign
- Well-formed channels lined by a single layer of bland endothelium: haemangiomas (infantile, cherry, cavernous), pyogenic granuloma, lymphangioma.
- Intermediate
- Locally aggressive (kaposiform haemangioendothelioma) or rarely metastasising (Kaposi sarcoma).
- Malignant
- Angiosarcoma, and the rarer epithelioid haemangioendothelioma.
US spelling: tumours → tumors, tumour → tumor, haemangiomas → hemangiomas.
Normal function
Endothelium, small vessels and lymphatics
Every vessel is lined by endothelium, a single layer of flat cells on a basement membrane. In that is almost the whole wall, wrapped by occasional pericytes; add a ring of smooth muscle, and collect blood back towards the veins. Endothelial cells carry markers such as CD31 and ERG, which pathologists use to recognise vascular tumours.
Lymphatic capillaries are blind-ended tubes of thin endothelium with a patchy basement membrane, opening to take up tissue fluid; larger lymphatics have valves and carry lymph to the nodes. Lymphatic endothelium also expresses podoplanin (stained by D2-40) and PROX1.
In adults endothelial cells rarely divide. New vessels sprout only when signals such as VEGF call for them, as in wound healing or the menstrual cycle, and stop when the signal fades.
Underlying change · Step 1 of 5
Tumour or malformation, benign to malignant
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 2 of 5
Haemangiomas, pyogenic granuloma and lymphangioma
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 5
Kaposi sarcoma: a virus and weakened immunity
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 4 of 5
Angiosarcoma: malignant endothelium
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 5 of 5
Bleeding, trapped platelets and spread; grade and stage
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .