Dural metastasis: An uncommon form of recurrence in malignant sinonasal tumours

Dural metastases are an unusual form of spread in treated sinonasal malignancies. An analysis is presented of 20 cases of dural metastases diagnosed during imaging follow-up in a selection of cases in which anterior craniofacial resection was performed. They included 12 undifferentiated sinonasal carcinomas, 7 olfactory neuroblastomas, and 1 adenoid cystic carcinoma case. Dural metastases appeared on an average of 7.3 years after treatment in olfactory neuroblastoma. The maximum distance from malignancy to dural metastases was 14 cm for olfactory neuroblastoma, and 4.3 cm for undifferentiated sinonasal carcinoma. Dural metastases in the Burr holes were observed in 50% of undifferentiated sinonasal carcinoma, and 29% of olfactory neuroblastomas. Dural metastases presented as a nodular (60%), multinodular (10%), cystic (15%), and plaque (15%) pattern. These are suggestive of a local venous spread mechanism related to tumour rupture during surgery of anterior cranial fossa. Long-term follow-up with cranial inclusion would be indicated, given the possible late and distant presentation of dural metastases.