Vascular birthmarks and infantile haemangioma — branching viva

Opening question

Examiner: Take me through this infant. What is the lesion, and how do you frame it? [2]

Candidate: This is an infantile haemangioma — a proliferating vascular tumour that was absent at birth, appeared in the first weeks of life, and is now in its rapid proliferative phase. My frame is the two-family fork: vascular tumours proliferate through endothelial growth and then involute, while vascular malformations are structural errors present at birth that grow only with the child. Because this lesion is large and segmental on the face, it carries the highest risk of a syndrome, so my priorities are to classify it, to screen it, and to treat it in the proliferative phase while the window for propranolol is open. [2] [11]

Examiner: Walk me through the classification. [6]

Candidate: The Mulliken and International Society for the Study of Vascular Anomalies framework divides vascular anomalies into two families. Vascular tumours include infantile haemangioma, the congenital haemangiomas (rapidly involuting, non-involuting and partially involuting), kaposiform haemangioendothelioma and tufted angioma, and pyogenic granuloma. Vascular malformations include the capillary port-wine stain, venous, lymphatic and arteriovenous malformations, and the combined syndromes such as Klippel-Trenaunay and Sturge-Weber. The decisive distinction is cellular behaviour: tumours proliferate, malformations do not. [6] [11]

Branch 1 — pathophysiology

Examiner: What makes infantile haemangioma proliferate, and why does it involute? [11]

Candidate: Infantile haemangioma arises from a clone of endothelial cells driven into rapid proliferation, fuelled by pro-angiogenic signalling including the RAS pathway. The proliferating cells express GLUT1, the glucose transporter, which is the single most useful marker because it persists in the lesion and is absent from congenital haemangiomas and malformations. After the proliferative phase, which runs to around nine months, the proliferating endothelium undergoes apoptosis and is replaced by fibrofatty tissue, which is why the lesion involutes and leaves a residue. [11]

Examiner: Why does propranolol work on this lesion? [1]

Candidate: Propranolol halts proliferation and accelerates involution through three mechanisms. Early vasoconstriction reduces blood flow to the lesion, down-regulation of angiogenic signalling stops new vessel growth, and induction of endothelial apoptosis removes the proliferated cells. This is why a proliferating tumour responds to a beta-blocker and why a static malformation does not. The dose is 2 to 3 mg per kg per day in divided doses, started in the proliferative phase and continued to around twelve months. [1] [7]

Branch 2 — syndrome screening

Examiner: This lesion is large and segmental on the face. What does that mandate? [8]

Candidate: A large or segmental facial haemangioma mandates a PHACE syndrome screen. PHACE stands for posterior-fossa brain malformations, the large segmental facial haemangioma, arterial anomalies of the cerebral and cervical circulation, cardiac defects (particularly aortic arch and coarctation), and eye anomalies, with an S added for sternal cleft and supraumbilical raphe. The screen is brain and neck MRI with MR angiography, echocardiography, and ophthalmology review. Because the cerebral arterial anomalies carry a small stroke risk during propranolol initiation, I would initiate propranolol under specialist supervision once the vascular anatomy is defined. [8] [7]

Examiner: And if the lesion were in the lumbosacral midline? [11]

Candidate: Then the screen is for LUMBAR syndrome and occult spinal dysraphism — lower-body haemangioma with urogenital, myelodysplasia, bony, anorectal and renal anomalies. I would image the spine with ultrasound in the young infant or MRI, examine for other cutaneous markers such as a dimple or hair tuft, and refer to neurosurgery or urology as the imaging dictates. The skin lesion is the visible marker of a hidden spinal problem. [11]

Branch 3 — treatment pathway

Examiner: How do you decide between observation and treatment for a haemangioma? [2]

Candidate: The decision turns on risk. A small, focal haemangioma in a non-critical site, not ulcerated and not near the eye or airway, is managed with active observation and counselling, because most haemangiomas need no treatment. A problematic lesion — periocular, airway, large, segmental, ulcerated, or one that risks permanent disfigurement — is treated. For small superficial lesions I use topical timolol 0.5 percent gel-forming solution; for the rest I use oral propranolol 2 to 3 mg per kg per day. The principle is treat the ones that need it, early, and reassure the family about the rest. [2] [11]

Examiner: What do you tell the family about propranolol before you start? [7]

Candidate: I explain the hypoglycaemia risk, particularly with intercurrent illness and poor feeding, and that they should maintain feeding during illness and bring the infant in if she becomes pale, limp or lethargic. I warn about bradycardia and hypotension and the need to hold the dose during significant respiratory illness given the reactive-airway risk. I perform a basic cardiac check first to exclude significant bradycardia, heart block or aortic obstruction. And because the lesion is segmental facial, I confirm the PHACE workup is underway before initiation, given the rare stroke risk of cerebral arterial anomalies. [7] [8]

Branch 4 — port-wine stain and malformations

Examiner: Move on. A newborn has a flat, dark-red patch on the forehead present from birth. What is it, and how do you manage it? [4]

Candidate: That is a capillary malformation, a port-wine stain. Unlike a haemangioma it was present at birth, is flat, and will never regress — it darkens to purple and develops cobblestoned nodules over decades. It is caused by a somatic mosaic activating GNAQ mutation that drives constitutive signalling in dilated dermal capillaries. I refer early for pulsed-dye laser, because results are best when the skin is thin in infancy, and I evaluate for Sturge-Weber syndrome, because a forehead or upper-eyelid stain raises the possibility of a leptomeningeal angioma with seizures and glaucoma. [4] [6]

Examiner: Does propranolol help a port-wine stain? [6]

Candidate: No. Propranolol works on proliferating endothelium, and a port-wine stain is a fixed structural malformation with no proliferative drive. Propranolol has no role in its management. The treatment is pulsed-dye laser and, where a syndrome is present, multidisciplinary care. This is the practical consequence of the fork: a tumour takes a beta-blocker, a malformation takes a laser. [6]

Branch 5 — the dangerous differential

Examiner: Finally, an infant has a rapidly enlarging, firm, purpuric vascular tumour with bruising and a platelet count that is falling. What is your concern? [11]

Candidate: That is the Kasabach-Merritt phenomenon — a consumptive coagulopathy with thrombocytopenia caused by kaposiform haemangioendothelioma or tufted angioma. It is almost never caused by ordinary infantile haemangioma, and the distinction is critical because propranolol does not treat it. I would check the full blood count and coagulation, refer urgently to a vascular-anomalies or haematology-oncology specialist, and expect treatment with sirolimus or vincristine rather than a beta-blocker. [11] [6]

Examiner: Summarise the vascular-birthmark stance in one sentence. [2]

Candidate: Classify by the tumour-versus-malformation fork, treat the problematic infantile haemangioma early with propranolol in the proliferative phase, screen the segmental and midline lesion for its syndrome, refer the malformation for laser and multidisciplinary care, and never confuse the Kasabach-Merritt phenomenon with infantile haemangioma — because a vascular birthmark is harmless until its site, its pattern or its biology makes it not. [2] [1]