see also: Case Example Deep Lobe Parotid Tumor Parapharyngeal Space and Pleomorphic Adenoma

• Benign, slow-growing, heterogenous tumor made up of epithelial, myoepithelial, and stromal components (Hernandez-Prera 2021, Kalwaniya 2023)
• Most common salivary gland neoplasm (Hernandez-Prera 2021)
• Most common in 4th through 6th decades of life, 60% in females (Kalwaniya 2023)
• Typically presents as a "painless, slow-growing firm or hard mass, which progressively enlarges" (Chalard 2022)
• Treatment involves facial-nerve-sparing parotidectomy to reduce recurrence risk (Chalard 2022)
• Malignant transformation to carcinoma ex-pleomorphic adenoma can occur if incompletely excised (Kalwaniya 2023)
  • Signs of malignant transformation may include rapid growth of known pleomorphic adenoma, or new pain, facial nerve paralysis, skin ulceration/fixation, or lymphadenopathy (Kalwaniya 2023)
• Small pleomorphic adenomas can be homogeneously enhancing and well-circumscribed (Kalwaniya 2023)
• Large tumors may be heterogeneous due to necrosis, hemorrhage, or cysts (Chalard 2022, Kalwaniya 2023)
• Tumors involving the deep lobe (less common than superficial) may push into the parapharyngeal space medially (Kalwaniya 2023)
• Ultrasound imaging shows a hypoechoic texture with "well-defined border with lobules, either with or without posterior acoustic enhancement" (Kalwaniya 2023)

References

Kalwaniya DS, Meena R, Kumar D, Tolat A, Arya SV. A Review of the Current Literature on Pleomorphic Adenoma. Cureus. 2023 Jul 22;15(7):e42311. doi: 10.7759/cureus.42311. PMID: 37614271; PMCID: PMC10442517.

Chalard F, Hermann AL, Elmaleh-Bergès M, Ducou le Pointe H. Imaging of parotid anomalies in infants and children. Insights Imaging. 2022 Feb 24;13(1):27. doi: 10.1186/s13244-022-01166-y. Erratum in: Insights Imaging. 2022 May 6;13(1):86. PMID: 35201515; PMCID: PMC8873326.

Hernandez-Prera JC, Skálová A, Franchi A, Rinaldo A, Vander Poorten V, Zbären P, Ferlito A, Wenig BM. Pleomorphic adenoma: the great mimicker of malignancy. Histopathology. 2021 Sep;79(3):279-290. doi: 10.1111/his.14322. Epub 2021 Apr 22. PMID: 33368685.