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Vascular Tumors & Malformations

Name: Vascular Tumors & Malformations
Creator: Veli Bakalov, MD

Which red lesions grow and fade, which persist for life, and which can kill

Cardiovascular·Vascular Pathology & Hypertension·6 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

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Vascular tumors proliferate (infantile hemangioma is GLUT1-positive and involutes over years); malformations are present at birth, grow with the child, and never regress.
Infantile hemangioma appears in the first weeks, grows for 3–5 months, then fades; oral propranolol treats lesions that threaten vision or the airway, ulcerate, or will disfigure.
Pyogenic granuloma is a friable, bleeding lobular capillary hemangioma provoked by trauma or pregnancy (gingiva); cherry hemangiomas are harmless adult papules that never regress.
Glomus tumor is a painful, cold-sensitive blue-red subungual nodule of modified smooth muscle cells from the thermoregulatory glomus body.
Cystic hygroma is a posterior-neck lymphatic malformation associated with Turner syndrome (45,X) and trisomy 21.
Sturge-Weber syndrome: sporadic somatic GNAQ mutation; V1 port-wine stain, ipsilateral leptomeningeal angioma with tram-track calcifications, seizures, hemiparesis, intellectual disability, and glaucoma.
HHT is autosomal dominant (ENG, ACVRL1): epistaxis, mucocutaneous telangiectasias, GI bleeding, and pulmonary AVMs that cause paradoxical stroke or brain abscess.
In AIDS, purple papules with neutrophils and silver-staining Bartonella are bacillary angiomatosis (erythromycin or doxycycline); spindle cells with lymphocytes are HHV-8 Kaposi sarcoma.
Angiosarcoma is CD31-positive; hepatic cases follow vinyl chloride, arsenic, or Thorotrast, and cutaneous cases follow radiation or chronic lymphedema (Stewart-Treves syndrome).

Tumors versus malformations

Two biologies. Vascular tumors are proliferations of endothelial cells with a growth phase: infantile hemangioma, pyogenic granuloma, Kaposi sarcoma, and angiosarcoma. Vascular malformations are errors in forming capillaries, veins, lymphatics, or arteriovenous connections. They are present at birth (even if not yet visible), grow only in proportion to the child, and never involute. Examples are port-wine stains, lymphatic malformations such as cystic hygroma, and the telangiectasias and arteriovenous malformations (AVMs) of hereditary hemorrhagic telangiectasia.

GLUT1. The endothelium of infantile hemangioma expresses the glucose transporter GLUT1, and malformations do not. CD31 stains endothelium in both, so it cannot separate them.

Benign vascular tumors

Infantile (strawberry) hemangioma. This is the most common tumor of infancy, more frequent in girls and preterm infants. It is absent, or only a faint mark, at birth and appears within the first weeks. It proliferates over roughly 3–5 months, then involutes slowly over several years, often leaving telangiectasias or fibrofatty residue.

When to treat. Most are observed. Oral propranolol, a nonselective β-blocker, is first-line when a lesion threatens vision (periocular lesions cause amblyopia) or the airway (a beard-area hemangioma may accompany a subglottic one), ulcerates, or will disfigure. Systemic corticosteroids are now second-line. Watch for hypoglycemia, bradycardia, hypotension, and bronchospasm.

A large segmental facial hemangioma should prompt evaluation for PHACE syndrome: posterior fossa malformations, hemangioma, arterial anomalies, cardiac defects such as coarctation, and eye anomalies.

Benign vascular tumors at a glance

Lesion	Typical patient	Appearance and course	Key point
Infantile hemangioma	Infants; girls, preterm	Appears in the first weeks, grows for months, involutes over years	GLUT1-positive; propranolol when problematic
Cherry hemangioma	Middle-aged and older adults	Small bright-red papules on the trunk and arms; multiply with age, never regress	Harmless; cosmetic removal only
Pyogenic granuloma	Any age; pregnant women	Rapid, polypoid, friable nodule that ulcerates and bleeds	Trauma; pregnancy (gingiva)
Glomus tumor	Adults	Small blue-red nodule under a nail	Paroxysmal pain, point tenderness, cold sensitivity

Pyogenic granuloma. Also called lobular capillary hemangioma, this rapidly growing, polypoid red nodule on the fingers, lips, or gingiva ulcerates and bleeds with trivial contact. Trauma and pregnancy are the classic triggers, and the gingival "pregnancy tumor" often regresses after delivery. Excision or curettage with cautery treats it. The name is a double misnomer: the lesion is neither infectious nor granulomatous, just lobules of capillaries in inflamed stroma.

Glomus tumor. It arises from the modified smooth muscle (glomus) cells of the glomus body, a thermoregulatory arteriovenous shunt in the dermis that is densest in the fingertips. Excision is curative. Glomus jugulare and tympanicum tumors are unrelated; they are paragangliomas of neural crest origin.

Vascular and lymphatic malformations

Port-wine stain. This capillary malformation (nevus flammeus) is a flat pink-purple patch present at birth. It grows with the child, never regresses, and darkens and thickens over decades. It is usually unilateral on the face, most lesions carry a somatic GNAQ mutation, and pulsed-dye laser lightens it. The common midline "salmon patch" (stork bite), by contrast, usually fades.

Sturge-Weber syndrome. A sporadic, postzygotic activating GNAQ mutation produces a port-wine stain in the ophthalmic (V1) distribution and an ipsilateral leptomeningeal capillary-venous malformation. Venous stasis makes the underlying cortex ischemic, and it atrophies and calcifies in a gyriform, "tram-track" pattern. The results are seizures from infancy, contralateral hemiparesis, and intellectual disability, plus ipsilateral glaucoma. The mutation is somatic, so the syndrome is not inherited. The germline neurocutaneous syndromes differ: tuberous sclerosis (TSC1/TSC2), NF1 (Lisch nodules), and von Hippel-Lindau (retinal hemangioblastomas).

Cystic hygroma. This macrocystic lymphatic malformation (older name: cavernous lymphangioma) is a soft, compressible, transilluminating mass, classically in the posterior neck. It is often seen on prenatal ultrasound and is associated with Turner syndrome (45,X), trisomies 21, 18, and 13, and fetal hydrops. In Turner syndrome, a nuchal hygroma that resolves leaves a webbed neck.

Hereditary hemorrhagic telangiectasia (HHT). Osler-Weber-Rendu syndrome is autosomal dominant. It is caused mainly by ENG (endoglin; HHT1) or ACVRL1 (ALK1; HHT2), both in endothelial TGF-β/BMP signaling. SMAD4 mutations cause a combined juvenile polyposis and HHT syndrome. Recurrent epistaxis, often starting in childhood, is usually the first sign. Telangiectasias appear on the lips, tongue, and fingertips, and GI telangiectasias bleed chronically, causing iron-deficiency anemia.

Visceral AVMs. In HHT, arteries connect directly to veins without capillaries. Pulmonary AVMs cause a right-to-left shunt with hypoxemia, cyanosis, clubbing, and polycythemia. They also let venous clots and bacteria reach the brain as paradoxical emboli, causing stroke or brain abscess. Cerebral AVMs bleed, and hepatic AVMs can cause high-output heart failure. Screen with bubble echocardiography and brain MRI. ENG mutations favor pulmonary and cerebral AVMs, and ACVRL1 mutations favor hepatic AVMs.

Until pulmonary AVMs are embolized, patients need antibiotic prophylaxis before dental work and air-free IV lines, because anything entering a vein can reach the brain.

Spider angiomas. A central arteriole with radiating branches blanches when the center is pressed. The lesions cluster in the SVC drainage area of the face, neck, upper trunk, and arms. Many lesions suggest hyperestrogenism. In cirrhosis, the liver clears less estrogen and more androgen is converted to estrogen; pregnancy and estrogen therapy are the other causes. Caput medusae, in contrast, reflects portal hypertension.

Infectious and malignant look-alikes

Bacillary angiomatosis. In advanced AIDS (CD4 usually below 100/μL), Bartonella henselae (cats) or B. quintana (body lice) stimulates capillary growth. The resulting red-purple papules mimic Kaposi sarcoma. Biopsy shows plump endothelial cells, neutrophils, and bacilli on Warthin-Starry silver stain. Erythromycin or doxycycline cures it.

Purple lesions: infection vs neoplasm

Feature	Bacillary angiomatosis	Kaposi sarcoma	Angiosarcoma
Cause	Bartonella henselae or quintana	HHV-8	Vinyl chloride, arsenic, Thorotrast; radiation; lymphedema
Histology	Capillaries, neutrophils, silver-staining bacilli	Spindle cells, slit-like spaces, extravasated RBCs, lymphocytes	Atypical endothelial cells in anastomosing channels
Treatment	Erythromycin or doxycycline	ART; less immunosuppression; liposomal doxorubicin	Surgery; poor prognosis

Kaposi sarcoma. HHV-8 drives an endothelial-derived tumor of spindle cells lining slit-like spaces with extravasated red cells and lymphocytes. It occurs in four settings:

Classic: older men of Mediterranean or Eastern European Jewish descent, with indolent lower-leg plaques.
AIDS-associated: AIDS-defining; involves the skin, hard palate, GI tract, and lungs, and regresses with ART.
Transplant: improves when immunosuppression is reduced.
Endemic: African children and young adults.

HHV-8 also causes primary effusion lymphoma and multicentric Castleman disease.

Angiosarcoma. This aggressive malignant endothelial tumor is positive for CD31, CD34, and ERG. It arises on the scalp and face of the elderly, in the breast, and in the liver. Hepatic angiosarcoma follows vinyl chloride (PVC manufacturing), arsenic, or Thorotrast. Other cases arise in irradiated skin or in an arm with chronic lymphedema after mastectomy with axillary dissection (Stewart-Treves syndrome). These secondary tumors typically show MYC amplification. In that arm, CD31 positivity separates angiosarcoma from recurrent breast carcinoma, which is cytokeratin-positive.