A large lobulated enhancing mass is centred on the sacrum completely effacing the sacral canal and displacing pelvic content anteriorly. It is bright on T2 and low signal on T1 with prominent enhancement.
Case Discussion
The patient went on to have a biopsy.
Histology
The sections show a soft tissue proliferation composed of a myxoid spindle cell matrix within which are dispersed vascular structures of varying diameter and thicknesses, typical of a haemangioma. The spindle cell matrix is considered reactive and coexists with fresh haemorrhage and haemosiderin deposition. The lesional tissue is present at the biopsy margins.
Final diagnosis: intraosseus haemangioma.