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Vascular Tumors

Tumores vasorum

For medical students2 min readUpdated 2026-10-10

Vascular tumors develop from blood vessels (hemangiomas) or lymphatic vessels (lymphangiomas). Up to 70% of benign angiomas are congenital, and their true nature—whether neoplastic or a congenital malformation—remains a subject of debate.

Congenital angiomas70% of benign vascular tumors

Benign formsCapillary, cavernous, telangiectasias

Intermediate groupBenign morphology, invasive growth

Malignant formsClassified as sarcomas

General Characteristics and Features

Vascular neoplasms are divided into two main groups based on their origin: hemangiomas (from blood vessels) and lymphangiomas (from lymphatic vessels).

These tumors are characterized by slow, expansive growth.
Approximately 70% of benign forms are congenital.
There is an ongoing debate in the medical community as to whether these lesions represent true neoplasms or developmental malformations (hamartomas).
Malignant variants of vascular neoplasms are classified as sarcomas.

Benign Vascular Tumors and Telangiectasias

Benign hemangiomas are divided into four main types: capillary, cavernous, sclerosing hemangiomas, and telangiectasias.

Telangiectasias are tangles of capillaries, venules, and arterioles, typically localized to the skin and mucous membranes. They can be congenital or acquired (e.g., due to radiation or circulatory insufficiency). A special variety includes spider telangiectasias (spider angiomas), which are 2–5 mm in diameter with radial branches, frequently seen in patients with liver cirrhosis and pregnant women.

Lymphangiomas and Glomus Tumors

Lymphangiomas are divided into simple (capillary), cavernous, and cystic (hygromas).

Capillary and cavernous forms resemble hemangiomas but differ by the absence of blood in their spaces and the presence of lymphocytes and lymphoid follicles.
Cystic lymphangiomas (hygromas) commonly occur in the neck and axillary region as multilocular masses filled with clear lymph.

Glomus tumor (Masson's tumor) arises from glomus-type arteriovenous anastomoses (thermoregulatory receptors). It is located predominantly on the distal phalanges and in the subungual space, causing marked pain and a bluish-red nodule.

Intermediate and Malignant Vascular Tumors

Intermediate-group vascular tumors have a benign microscopic structure but behave clinically like malignant tumors due to their invasive growth:

Hemangioendothelioma — a type of capillary tumor consisting of solid masses of proliferating endothelial cells, where only a fraction of capillaries remain functional. It typically occurs in young individuals.
Hemangiopericytoma — a neoplasm composed of capillaries surrounded by clusters of cells derived from pericytes.

Malignant variants of vascular tumors are categorized separately as sarcomas.

Mnemonic

Lymphangioma is like a hemangioma, but without blood: instead, lymph fills the vascular spaces, and lymphoid follicles hide within the stroma.

Frequently asked questions

What are the causes of acquired telangiectasias?

Acquired telangiectasias are caused by circulatory insufficiency, ataxia-telangiectasia (Louis-Bar syndrome), and ionizing radiation exposure. Spider telangiectasias occur in patients with liver cirrhosis and sometimes during pregnancy.

What is the microscopic structure of a cavernous hemangioma?

The microscopic structure of a cavernous hemangioma consists of large, dilated vascular spaces (caverns) of varying sizes.

Vascular spaces — lined by a single layer of endothelium and communicating with each other through anastomoses.
Lumen contents — filled with blood or thrombotic masses.
Stroma — composed of thin connective tissue septa separating the caverns.
Capsule — the tumor features a fibrous capsule.

The walls of the vascular spaces in such tumors may vary in thickness.

What specific types of malignant vascular tumors are identified in classifications?

Classifications identify the following specific types of malignant vascular tumors:

Angiosarcoma — a malignant tumor of blood vessels (ICD-O code 9120/3).
Epithelioid hemangioendothelioma, NOS (not otherwise specified, ICD-O code 9133/3) — includes genetic variants with WWTR1-CAMTA1 fusion and YAP1-TFE3 fusion.

All malignant variants of vascular neoplasms are classified as sarcomas. Note that Kaposi sarcoma is classified among intermediate (rarely metastasizing) forms.

How does a capillary hemangioma differ histologically from a cavernous hemangioma?

A capillary hemangioma consists of closely packed, thin-walled, differentiated capillaries and small endothelium-lined spaces with a scant stroma. A cavernous hemangioma consists of large vascular spaces of varying sizes lined by a single layer of endothelium, filled with blood or thrombi, and separated by thin connective tissue septa. In cavernous hemangiomas, the vascular spaces may communicate via anastomoses.

What is the main morphological difference between capillary lymphangiomas and hemangiomas?

In lymphangiomas, erythrocytes and blood are entirely absent from the vascular spaces, whereas clusters of lymphocytes and lymphoid follicles are found in the surrounding tissue.

Why is hemangioendothelioma classified in the intermediate group?

Because despite a relatively benign histological appearance, this tumor exhibits a propensity for invasive, aggressive growth.

Where is a glomus tumor most commonly localized and what is its clinical presentation?

It is localized on the distal phalanges of the fingers and toes, particularly in the subungual space, presenting as a painful bluish-red nodule.

Go deeper

Histological findings in sclerosing hemangiomas (hemosiderin, foreign body giant cells)
Complications of vascular tumors (ulceration, hemorrhage, infection)
Structure and microscopy of glomus cells in Masson's tumor
Macroscopic appearance of cystic lymphangiomas (hygromas) of the neck
Clinicopathological features of hemangiopericytoma