Metastasising pleomorphic salivary gland adenoma presenting as synchronous pulmonary and hepatic metastases

Abstract

Pleomorphic salivary adenomas (PAs) are the commonest benign tumours of glandular origin in the head and neck. Occasionally PAs undergo malignant transformation to carcinoma-ex-PA and can metastasise. More rarely they metastasise without malignant transformation of the primary tumour. We present a case of a benign pleomorphic salivary gland adenoma, presenting 7 years later with multiple liver metastases and a synchronous pulmonary metastasis. Histological analysis of the lung and liver lesions confirmed a diagnosis of metastasising pleomorphic adenoma (MPA). The lung lesion was fully excised, but the multifocal nature of the liver lesions rendered them inoperable. The patient is being managed conservatively and to date has no local recurrence of the primary salivary gland tumour or any further metastases. To the best of our knowledge this is the first case of MPA with simultaneous metastasis to both lungs and liver, and also the first to describe multiple liver metastases.

A case of initially metastasizing pleomorphic adenoma of parotid gland

“…Multiple metastases and distant metastasis have been reported as important predictive values for poor prognosis. 5 , 9 , 14 Knight et al reported that 8 out of 13 patients with more than three multiple metastases died within 3 years after diagnosis of MPA, and 5 others were not followed up. 9 Distant metastasis of MPA was reported as significantly associated with morbidity and mortality rate and the 5-year disease-specific and disease-free survival rate of MPA with distant metastasis were 58% and 50%, respectively.…”

Cystadenofibroma with Mullerian-Type Epithelium and Stroma in the Liver: A Report of an Unusual Diagnosis and Discussion of Possible Etiologies

“…19 Benign tumor shedding may have occurred prior to the patient's oophorectomy or during the procedure leading to a benign "metastasis" from implanted tumor cells similar to dissemination of benign salivary gland tumors to the liver. 20,21 Unfortunately, the patient's prior pathology was not available to further evaluate this possibility.…”