Mucoepidermoid carcinoma of unknown primary (MEC-UP) in the head and neck is a rare presentation of the most common salivary gland cancer. Cancers of unknown primary sites often have poorer prognoses than similar cancers with known primary. Few cases of MEC-UP have been reported; therefore, the objective of this report is an overview of the diagnosis and management of MEC-UP.

We present two patients with low-grade MEC-UP at a high-volume tertiary care institution in Ontario, and a database search returning 1560 citations of which five studies with seven MEC-UP cases were identified.

Review of the limited cases suggest many clinicians use positron emission tomography-computed tomography (PET-CT) in addition to panendoscopy and targeted biopsies with consideration for diagnostic tonsillectomy in diagnostic work-up.

Like other salivary gland cancers, primary therapeutic surgical resection is recommended with low threshold for adjuvant radiotherapy to regions at high risk for harbouring the primary malignancy, especially in cases of high-grade histopathology.

Ceruminous mucoepidermoid carcinoma of the external auditory canal is extremely rare. This paper highlights the impact of concurrent chemoradiotherapy on the outcomes of this disease.

A 47-year-old female presented with a 2-month history of otalgia and a mass in her right ear. Biopsy revealed high grade ceruminous mucoepidermoid carcinoma. She underwent surgical excision of the right external auditory canal and right upper neck dissection. Pathological analysis of tumour–node–metastasis staging revealed a T2 N0 (stage II) tumour. One year later, computed tomography scanning of the temporal bone showed tumour recurrence. Biopsy revealed recurrent ceruminous mucoepidermoid carcinoma. The patient underwent salvage resection. Pathology revealed that the tumour was diffusely invading nearby structures, with perineural invasion, lymphatic spread and extracapsular extension. Pathological analysis of tumour–node–metastasis staging revealed a T3 N1 M0 (recurrent stage IV) tumour.

The patient subsequently received concurrent chemoradiotherapy. There was no evidence of disease at 37 months' follow up.

The trimodality approach, using surgery plus concurrent chemoradiotherapy, provided reasonable loco-regional control with tolerable toxicity. Further detailed case reports are warranted to optimise the management of this rare malignancy.

Patients who survive malignant tumours have an increased risk of second neoplasms, including those of the salivary glands. Mucoepidermoid carcinoma of the parotid gland is by far the most common type of second salivary gland tumour; other types have rarely been reported. We describe here two patients with a second tumour of the salivary glands.

The first patient was a 22-year-old woman with a low grade mucoepidermoid carcinoma of the parotid gland, which developed 21 years after completion of chemoradiotherapy for acute lymphoblastic leukaemia. The second patient was a 40-year-old woman with an epithelial-myoepithelial carcinoma of the buccal mucosa, which arose 11 years after treatment for two malignant neoplasms – retroperitoneal liposarcoma and squamous cell carcinoma of the uterine cervix.

It is mandatory that survivors of cancer should be monitored carefully, so that the complications related to their previous disease and therapy are detected early and managed properly.