<p>A 34 year old lady presented with a new blue papule on the right upper arm. There was no other relevant history of note. What is the clinical differential? </p>
Dermoscopy - Introduction, Terminology and Structures
A document to help you understand the dermoscopic descriptions used in this blog.
Dermoscopy Algorithm
To help you work through dermoscopic cases.
<p>The lesion is asymmetrical. The vast majority of the lesion is a <strong>blue-black structureless area</strong>. There are a few irregular clods (black arrows), and a hint of some white lines (white arrow). Given the asymmetry and eccentric stuctureless area the most likely diagnosis is melanoma (refer to algorithm). A heavily pigmented BCC is the main differential, but without other features of a BCC such a diagnosis is unlikely. The features do <strong>not</strong> suggest a blue naevus, which are blue (or blue and white) and more symmetrical, as opposed to blue and black. The histology showed a melanoma with a breslow thickness of 0.8 mm. </p>
