Neoplastic Left Parotid Mass Proven as Squamous Cell Carcinoma

October 4, 2013
Doaa Ibrahim, MD

Case History: A 54-year-old female complaining of left parotid swelling for three months

Findings: MDCT contrast enhanced axial (Figs. A, B, C)and coronal (Figs. D, E) images showing ill defined heterogeneous enhanced soft tissue density mass involving both lobes of the left parotid gland. The lesion extending antero-medially inseparable from the pterygoid muscles (Fig. B - black arrow), with loss of the surrounding fat planes, additionally noted erosion of the medial superior aspect of the left mandible body (Fig. E - black arrow).

Diagnosis: Neoplastic left parotid mass pathologically proven as squamous cell carcinoma

Discussion: About 70 percent of all salivary gland neoplasms occur in the parotid gland. Several studies have investigated the value of computed tomography (CT) in distinguishing parotid gland tumours. The results of some documents have demonstrated that CT could identify patients with pleomorphic adenomas, Warthin’s tumors and malignant tumors, and evaluate the extent of parotid gland tumors.

Squamous cell carcinoma of the salivary glands represents a rare neoplasm that constitutes 0.3 percent to 1.5 percent of salivary gland tumors. This malignancy occurs more often in the submandibular gland than the parotid gland. Proper diagnosis of squamous cell carcinoma requires exclusion of contiguous spread of a squamous cell carcinoma into the gland, metastases to the gland, and high-grade mucoepidermoid carcinoma.

These tumors usually present as firm indurated masses and occur more commonly in males, usually in the seventh decade of life. Histologically, these tumors reveal intracellular keratinization, intercellular bridges, and keratin pearl formation. However, they do not produce mucus.PET scans may play a role but not in the initial diagnosis. False positives seen in inflammatory process limits its usefulness in distinguishing benign from malignant. PET scan cannot reliably distinguish benign from malignant process.

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Doaa Ibrahim, MD in radio-diagnosis, Zagazig University Hospitals and TechnoScan Centers in Egypt