Author: Naomi Ashman, Dermoscopist, Torbay Skin, Auckland, New Zealand. DermNet NZ Editor in Chief Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. June 2019.
In dermoscopy, angulated lines are straight lines that meet at angles larger than 90 degrees but do not intersect. They may form complete or partial polygonal shapes. They are also known as polygons, rhomboids and zigzag pattern. They are a dermoscopic clue to melanoma.
Angulated lines are grey-brown lines that are connected at an angle, or coalescing to form polygons.
Angulated lines are seen in the following skin lesions:
On the face, angulated lines correspond to rhomboids and are also represented in:
The precise histology is not clear but likely correlates with an accumulation of inflammatory cells and melanophages in the dermis, underneath the malignant melanocytes residing in the epidermis.
Angulated lines seem to correspond to a flattened dermoepidermal junction (DEJ) with fewer and more blunted rete pegs due to a proliferation of atypical melanocytes at the DEJ together with a focal accumulation of melanophages in the superficial dermis .
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