Report of a unique case of myoepithelial carcinoma of left parotid gland with metachronous bilateral cavernous sinus metastasis

Abstract

Myoepithelial carcinoma (MC) is a rare, locally aggressive malignant neoplasm of the salivary glands. Only few evidences on its metastatic behavior are available in the literature. We herein present a unique case of MC of left parotid gland which metastasized to bilateral cavernous sinuses. The patient was successfully treated with palliative radiotherapy and chemotherapy.

Parotid Myoepithelial Carcinoma in a Pediatric Patient with Multiple Recurrences: Case Report

“…Most MCs develop secondary to a pleomorphic adenoma or a preexisting benign myoepithelioma, generating a low-grade neoplasm. When they appear de novo, as in our case, they are usually high grade with a tendency towards clinical and radiological aggressiveness, in addition to a short evolution time [ 1 , 9 , 10 , 12 ]. A large clinical series reports that 75% of the MCs appear as “de novo” and 25% come from a previous benign tumor; other authors describe 50:50 ratios and even as low as 30% de novo MC [ 2 , 7 , 9 ].…”

“…Parotid MC accounts for <1–2% of salivary gland tumors in adults [ 2 , 9 , 10 ]. Up to the year 2015, only 150 cases of MC had been reported in the literature [ 9 , 11 ].…”

“…The parotid gland (29–82%) and the palate (21%) are the most frequent locations of myoepithelioma in the head and neck region [ 2 , 4 , 9 ]. MCs have also been reported in a variety of sites: jugal, gingival, buccal, nasopharyngeal, laryngeal, pharyngeal and parapharyngeal spaces, nasal cavity, alveolus, retromolar area, base of tongue, cavernous sinus, and maxillary sinus [ 9 , 10 ]. Also, MCs outside the head and neck have been reported in the ribs, kidney, bladder lacrimal gland, ocular conjunctiva, infratemporal fossa (as one of the recurrences in our case), lung, trachea, skin, breast, and vulva [ 3 , 7 , 9 , 14 , 15 ].…”

“…MC usually presents as a painless swelling, but more frequently with additional symptoms compared to benign ones such as long evolution, rapid growth, pain (10–29%), facial paralysis (10–15%), numbness of the tongue or lips, dysphagia, stone consistency, fixation to deep structures, and pathological lymphoid nodules [ 1 , 9 , 10 ]. In our case, the patient presented with an increase in the volume of the parotid region that was painful and fixated to deep structures, which strongly oriented towards a malignant character.…”

“…Imaging studies such as nuclear MRI, CT, and PET/CT are helpful to determine tumor extension, as well as in identifying metastases and recurrences [ 1 , 12 ]. However, MRI delineates salivary gland tumors more clearly and is useful in detecting facial nerve compromise, so it is considered the optimal imaging modality [ 9 , 10 ]. The final diagnosis is given by the pathologist with a tissue biopsy [ 9 ].…”