LAUSR

exclude SCC or glomus tumour. We undertook a proximal trapdoor nail avulsion and reflected the proximal nail fold; however, no obvious abnormality was seen aside from a slight fullness of the matrix. This was incised to reveal a possible submatrix glomus tumour (Fig. 1b). An irregularly shaped piece of cream-coloured tissue measuring 7 9 3 9 2 mm was excised and sent for histopathological examination. Histology of the excised tissue showed that the tumour contained prominent, thick-walled blood vessels, consistent with the clinical impression of a cirsoid aneurysm, an entity that is typically composed of a network of interconnected and closely opposed venous and arterial vessels with prominent fibromuscular walls, and is a rare finding at this site. There was no evidence of glomus tumour, which would have been identifiable by solid sheets of glomus cells around small blood vessels. Cirsoid aneurysms usually arise in the head and neck region, and present as well-circumcised small reddish/ blue papules. Unlike glomus tumours, they are not usually spontaneously painful and do not exhibit temperature sensitivity. They were first described in skin in 1956, but it was not until 1986 when Burge et al. outlined three cases of confirmed subungual cirsoid aneurysms. They presented similarly to the case outlined here. Complete excision at the time of biopsy serves both diagnostic and treatment purposes, and helps exclude more sinister causes such as SCC and MM. Excision was curative in this case, as when the patient returned to clinic a few months later, the overall appearance of her nail was improved (Fig. 1c). Although rare, cirsoid aneurysms should be included in the differential diagnosis of linear erythronychia.