Targetoid haemosiderotic haemangioma: dermoscopic monitoring of three cases and review of the literature.

Targetoid haemosiderotic haemangioma represents a new, rarely reported, distinctive, benign vascular tumour, characterized histopathologically by a biphasic growth pattern of dilated vascular structures in the superficial dermis lined by prominent hobnail endothelial cells and collagen dissecting, rather narrow neoplastic vessels in deeper parts of the lesion. In the initial stage, the lesion is seen as a small purple or violaceous papule, 2--3 mm in diameter. Over time, the ecchymotic ring expands peripherally until it disappears spontaneously. In the later stages, however, the central papule remains as a slightly raised dermal lesion with a purple to brownish discolouration. We report three cases whose repetitive cyclic morphological changes of targetoid haemosiderotic haemangiomas were monitored dermoscopically at 3-month follow-ups. Histopathological examination of each lesion identified the features of targetoid haemosiderotic haemangioma. To the best of our knowledge, our three cases are the first reported in the literature of targetoid haemosiderotic haemangiomas that were regularly monitored by dermoscopic examinations, enabling development of the different stages of the same lesion to be followed.