Symmetrical ethmoidal metastases from ductal carcinoma of the breast, suggesting transcribrosal spread. While half of breast cancers develop metastases, the appearance of metastatic disease in paranasal sinuses from this origin is very rare. Eighteen other cases were found in the literature, dating from 1939 till now. A case of metastatic breastcancer presenting as a subacute therapy-resistant pansinusitis is described. The perfect symmetry was misleading. Bilateral ethmoidal biopsies were compatible with metastases from a ductal adenocarcinoma. Further investigation revealed meningeal carcinomatosis in the supra-orbital region and locoregional recurrence in the mastectomy scar and axilla. Comparing these 19 cases in chronological order, it was noticed that symptoms at time of diagnosis shift from those of space occupying lesions to those suggestive for sinusitis. This shift could be explained by earlier diagnosis. High index of suspicion is the key to diagnosis. Earlier diagnosis does not result in longer survival since in most cases patients have already widespread disease and die within one year. Most authors mention the role of the vertebral venous plexus in hematogeneous spreading of tumor cells. Another pathway of hematogenous spread is via (occult) lung metastases. This case prompts the hypothesis of transcribrosal spread from meningeal involvement.