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.
What do angulated lines look like through the dermatoscope?
Angulated lines are grey-brown lines that are connected at an angle, or coalescing to form polygons.
Angulated lines seen on dermoscopy of a small melanoma
Angulated lines are a clue to otherwise featureless melanoma
Angulated lines seen on dermoscopy of a small melanoma
In which lesions are angulated lines seen through the dermatoscope?
Angulated lines are seen in the following skin lesions:
Angulated lines seen on dermoscopy of lentigo maligna
Angulated lines seen on dermoscopy of actinic keratosis
Angulated lines seen on dermoscopy of melanoma
What is the histological explanation of angulated lines?
The precise histology is not clear but likely correlates with an accumulation of inflammatory cells and melanophages in the dermis, underneath the malignantmelanocytes residing in the epidermis.
Angulated lines seem to correspond to a flattened dermoepidermal junction (DEJ) with fewer and blunter rete pegs due to a proliferation of atypical melanocytes at the DEJ, as well as a focal accumulation of melanophages in the superficial dermis [1].
References
Vanden Daelen A, Ferreira I, Marot L, Tromme I. A digital dermoscopy follow-up illustration and a histopathologic correlation for angulated lines in extrafacial lentigo maligna. JAMA Dermatol 2016; 152: 200–3. DOI: 10.1001/jamadermatol.2015.4132. PubMed
Dermatoscopy, Pattern analysis of pigmented and non-pigmented lesions by Harold Kittler, Cliff Rosendahl, Alan Cameron, Philip Tschandl; 2nd edition, 2016; Facultas Verlags- und Buchandels AG facultas Universitatsverlag, Vienna, Austria.
