Pineal and leptomeningeal metastases from a parotid carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma (CEPA) is an uncommon complication of an untreated pleomorphic adenoma (PA), but one that has a life-threatening significance. This case report documents the clinical, radiological and histopathological features of an extremely rare case of biopsy-proven pineal metastasis, with cerebellopontine and leptomeningeal spread, from CEPA of the parotid gland in spite of the patient having undergone parotidectomy, ipsilateral neck dissection and adjuvant radiotherapy. In spite of the current surgical and oncological treatment of CEPA, the rates of recurrence and distant metastases are high, with a subsequently poor prognostic outcome in most patients. Distant spread is usually to the bones and the lungs; however, more unusual locations have been documented. Our finding of pineal metastasis from CEPA has not previously been reported in the literature. Although this is a rare complication of an unusual condition, the aggressive behaviour of these malignancies warrants close clinical follow-up, with a low threshold for re-imaging and investigation if indicated.