What lies beneath

Abstract

Haemangiopericytomas are a group of aggressive soft tissue sarcomas that originate from the pericytes in the walls of capillaries. Local invasion of the surrounding structures is not uncommon. Symptoms depend on the location, size and grade of tumour. Coexistence with a benign tumour in the same location is very rare. We report an interesting case of occipital scalp lipoma with an underlying torcular haemangiopericytoma and skull defect.

Figure 1

(A) An enhancing midline occipital lesion (4.5×6.5 cm) centred in the calvarium with overlying soft tissue mass, bony destruction and apparent invasion of the torcula. (B) Occipital bony destruction.

Figure 2

(A) T1 sagittal postgadolinium showing residual tumour. (B) T1 axial postgadolinium showing marked enhancement originating from the torcula. There was no definite evidence of superior sagittal sinus thrombosis. However, there was a filling defect consistent with tumour infiltration to the transverse sinuses. (C) T1 sagittal without contrast demonstrating occipital bone erosion. The residual tumour mass measured 2.6 cm (AP)×4.2 cm (transverse diameter)×6.5 cm (craniocaudal diameter). (D) T2 axial without contrast.