Sinonasal haemangiopericytoma-like tumour: a sinonasal glomus tumour or a haemangiopericytoma?

AIMS: Sinonasal haemangiopericytoma-like tumour is controversial with regard to its nosologic nature. This study aims to investigate its relationship with glomus tumour and haemangiopericytoma. METHODS AND
RESULTS: Six cases of sinonasal haemangiopericytoma-like tumours identified in our files were reviewed for clinicopathological features, and compared with five cases each of soft tissue glomus tumour and meningeal haemangiopericytoma. Immunohistochemical studies for muscle-specific actin, smooth muscle actin, desmin and CD34 were performed. Sinonasal haemangiopericytoma-like tumour demonstrated a uniform histological appearance with bland-looking short, spindly cells forming sheets and short fascicles. The tumour cells were interspersed with slit-like, round and ectatic blood vessels. Actin immunoreactivity was demonstrated in all six cases, although occasionally patchy. The histological appearance and immunohistochemical phenotype of sinonasal haemangiopericytoma-like tumour were very similar to and focally indistinguishable from glomus tumour. Meningeal haemangiopericytoma, in contrast, was characterized by high tumour cellularity, random nuclear orientation, presence of staghorn vasculature and lack of immunohistochemical evidence of myogenic differentiation.
CONCLUSIONS: We conclude that sinonasal haemangiopericytoma-like tumour is biologically close to or identical to glomus tumour, but is not related to haemangiopericytoma.