Usefulness of dermoscopy for the diagnosis of epidermal cyst: the ‘pore’ sign

Conflict of interest: the authors declare that they have no conflicts of interest. Epidermal cyst can usually be diagnosed clinically as a roughly circular subcutaneous nodule of variable size, of firm consistency, covered by smooth, normal‐coloured skin with a central punctum.1 However, it can be inflamed or, bluish, or may present with arborizing vessels,2 thus mimicking other skin lesions. The identification of the punctum, a pore corresponding to the follicle from which the cyst derives, gives a clue to the diagnosis. The pore is not always clinically evident (Fig. 1a), but dermoscopy can improve visualization1 (Fig. 1b). We aimed to assess whether dermoscopy can also help to distinguish the pore when it is not clinically visible. A prospective study was conducted on consecutive patients who presented with a roughly circular, firm, subcutaneous nodule. The age and sex of the patients, location of the nodule and presence of a central pore visible by clinical and/or dermoscopic (DermLite DL3, 3Gen, San Juan Capistrano, CA, USA) examination were recorded.