Vascular Patterns in Dermoscopy
When a lesion lacks pigment (amelanotic), its vascular morphology becomes the primary clue for diagnosis. Recognizing vascular patterns requires high-quality, polarized dermoscopy with minimal pressure.
Key Vascular Morphologies
Arborizing Vessels
Large, bright red vessels that branch into smaller, finer capillaries (tree-like). They are sharply in focus.
Primary Association: Basal Cell Carcinoma (BCC).
Dotted Vessels
Small, pinpoint red dots. They represent the tips of vertically arranged capillary loops.
Primary Association: Spitz nevi, clear cell acanthoma (string of pearls arrangement), psoriasis.
Hairpin Vessels
U-shaped or looped vessels, often surrounded by a whitish halo.
Primary Association: Seborrheic keratosis (especially keratinized/thick ones), Squamous Cell Carcinoma (SCC).
Crown Vessels
Vessels that curve around the periphery of a central white-yellow, structureless area.
Primary Association: Sebaceous hyperplasia, Molluscum contagiosum.
The Polymorphous Pattern
A polymorphous vascular pattern is the presence of two or more different types of vessels within the same lesion (e.g., dotted and linear irregular vessels).
Red Flag
A polymorphous vascular pattern in a pink, growing nodule is highly suspicious for Amelanotic Melanoma until proven otherwise. Urgent excision is required.