The patient may develop pain and tenderness which are usually due infiltration of the auriculo-temporal nerve with the pain being referred to the ipsilateral ear. Trismus due to invasion of the masseter or pterygoid muscles, or due to restricted movements of the temporo-mandibular joint (TMJ) is another finding.
In approximately 10% to 15% of the cases, the facial nerve will be paralyzed. Unequal pulsations of superficial temporal artery may as well be noticed. Manifestations of metastases to regional lymph nodes or distant organs such as the lungs or the liver may ensue. On the first suspicion of any change in the behavior of the pre-existing tumor, FNAC should be done immediately after MRI preferably with a diffusion-weighted and perfusion sequences.
Mucoepidermoid Carcinoma (MEC)
This is the commonest malignancy of the salivary glands (Foote, 1953; Shafique, 2020) and that of the parotid gland (80% of cases) seems to be less aggressive than that of the submandibular gland (8-13% of cases) and of better prognosis (Waldron & Koh, 1990). It mostly occurs around an age of 50 years, but still, it is the commonest salivary malignancy of the pediatric age group (Waldron, 1990; Browand, 1975). In some series, MEC is more common in women by a ratio of 3:2 while in others there is no sex predominance.
Low-grade and high-grade variants are recognized, where the low-grade one very rarely metastasizes (Boahene, 2004; Gustafsson, 1987). It usually presents as a slowly growing painless mass; however, rapid growth, pain and tenderness may be seen with the high-grade variant (Ogawa, 1992; Terada, 2004) (Figure 2). Metastases occur to LNs, lungs and bones (Waldron, 1990; Browand, 1975). Shafigue et al. (2020) studied the clinicopathological features of MEC using a 3-tier grading system (low, intermediate and high) in 69 patients. They reported that aggressive clinical behavior was seen in the high-grade MEC compared to the intermediate- and low-grade MEC.
Treatment is mucoepidermoid carcinoma (MEC) is surgical resection with neck dissection being reserved for high-grade variants (Boahene et al, 2004).
Prognosis is influenced by the grade and stage of the tumor, and patient's age (above 45 years is associated with poor prognosis) and gender. Histological grade is considered one of the most important factors in prognosis. The overall 5-year survival rates range from 92% to 100% for low-grade tumors, and 0% to 43% for high-grade tumors (Smith, Winkler, Perzin, Wazen, & Blitzer, 1985).
Figure 2. A rapidly growing (high-grade) muco-epidermoid carcinoma (MEC) in a 51-year-old gentle-man (A) that became fixed to the overlying skin (B) within two weeks