Metastasis is a feature of malignant neoplasms. Although rare, metastasizing pathologically benign mixed tumour has been reported. This report describes a 33-year-old woman with multiple lung metastases from mixed tumour. A small preauricular mass had been removed 23 years earlier. Six years later, the patient had the same symptom; the recurrent mass was resected. She was not aware of the exact pathological diagnosis of the previous tumours. One of the most common features of metastasizing mixed tumour is recurrence at the primary site. Inadequate resection of the primary tumour is often associated with metastasis. Thus, it is important for the head and neck surgeon to be aware of the concept of pathologically benign metastasizing mixed tumour and the importance of adequate surgical procedure.

Pleomorphic adenoma arising from the external auditory canal is a very rare neoplasm, and there has been no report on magnetic resonance (MR) imaging of pleomorphic adenoma of the external auditory canal. We report here a case of 65-year-old male with this tumour, measuring 12 mm in a diameter. Histopathology was confirmed from the specimen obtained at the surgical excision. MR revealed that the tumour had a well-defined margin showing hypointensity on T1-weighted images and hyperintensity on T2-weighted images relative to the parotid gland. The tumour was well enhanced by contrast material. No invasion to the surrounding tissue was observed. These MR findings were compatible with pleomorphic adenoma of the salivary gland origin. In treating pleomorphic adenoma of the external auditory canal, complete surgical excision is essential for the prevention of recurrence. It can be concluded that MR imaging is helpful for making a differential diagnosis of external auditory canal tumours and selection of adequate treatment.

To date there are only two recorded cases of patients with coexistent pleomorphic adenoma and myotonic dystrophy in the literature. We present two further cases, describe the general features of myotonic dystrophy and discuss the theory of a direct association between these two conditions.