Large plaque-like glomangioma in a patient with multiple glomus tumours: review of imaging and histology.

Glomus tumours are benign tumours of the temperature-sensitive neuromyoarterial glomus body, present within the dermis, which are most commonly seen as solitary subungual lesions on the arms. Multiple glomus tumours or glomangiomas are a less common subtype of extradigital glomus tumours, which very rarely present as large plaque-like dermal lesions. Glomangiomas do not often show the classic triad of symptoms associated with glomus tumours, namely: pain, point tenderness on compression, and temperature sensitivity. As a result of this and of their atypical morphology, they can often be misdiagnosed as vascular malformations (VMs), resulting in delayed diagnosis and inappropriate treatment. We report a 29-year-old man with multiple extradigital glomus tumours that had been present since childhood, with the lesion on the patient's leg being the largest plaque-like glomangioma yet reported, to our knowledge. Spectral greyscale and Doppler shift ultrasonography showed multiple, tubulonodular, ectatic, noncompressible, vascular structures with aberrant flow within the thickened dermis. Using magnetic resonance imaging, low to intermediate signal was seen on T1-weighted images and high signal on T2-weighted images, and there was florid enhancement with gadolinium, with no evidence of extension into muscle or bone. Histology showed abnormal, dilated, thin-walled, vascular channels lined with multiple layers of glomus cells, confirming the diagnosis of a glomangioma. We discuss imaging techniques for plaque-like glomangiomas, and review the clinical, radiological and histological characteristics that help differentiate them from other superficial VMs.