(A) Chemotherapy
(B) Cryotherapy
(C) Hormone therapy
(D) Immunotherapy
(E) Radiation therapy

The correct response is Option E.

Multinodular local tumors are the most common form of recurrence in patients with previously removed pleomorphic adenomas, and the most appropriate management of these tumors is radical resection followed by radiation therapy. The extent of resection depends on the nature of the recurrence and the extent of the previous surgery; however, the facial nerve should be preserved if possible. If the facial nerve cannot be preserved, immediate reconstruction with
a nerve graft is indicated. In addition, radiation therapy has been shown to result in a marked decrease in the risk for multinodular recurrence in patients with parotid gland tumors when compared with surgery alone.

Chemotherapy is not used for treatment of multinodular local recurrent pleomorphic adenomas. Cryotherapy is recommended for control of nonresectable hepatic tumors. Hormone therapy and immunotherapy are not appropriate management options in patients with parotid gland tumors.

References
1. Larsen DL. Management of the recurrent, benign tumor of the parotid gland. Plast Reconstr Surg. 2001;108:734.
2. Renehan A, Gleabe EN, McGurk M. An analysis of the treatment of 114 patients with recurrent pleomorphic adenomas of the parotid gland. Amer J Surg. 1996;172:7-10.

A 40-year-old woman has a painless mass at the angle of the left mandible that has been enlarging over the past 10 years; a photograph and CT scan are shown above. Findings on physical examination are otherwise normal. Histologic examination of a biopsy specimen of the tumor shows luminal-type ductal cells mixed with sheets of myoepithelial cells and a mucoid extracellular matrix.

Which of the following is the most likely diagnosis?

(A) Basal cell adenoma
(B) Myoepithelioma
(C) Pleomorphic adenoma
(D) Sjögren’s syndrome
(E) Warthin tumor

The correct response is Option C.

The most likely diagnosis in this patient is pleomorphic adenoma, or mixed tumor. This is the most common benign tumor of the parotid gland, comprising 65% of all salivary gland neoplasms, 55% of all parotid masses, and 80% of all benign parotid tumors. Most pleomorphic adenomas arise from within the superficial lobe of the gland; only 10% are located deep to the facial nerve. These encapsulated tumors contain both epithelial and mesenchymal elements within a stroma, which can vary from mucoid to myxoid to chondroid. Because small lobules of cells may extend beyond the capsule, simple enucleation frequently results in tumor recurrence. Therefore, appropriate management is superficial lobe parotidectomy with preservation of the facial nerve.

Basal cell adenoma is the most common type of monomorphic adenoma found in the minor salivary glands of the upper lip. These tumors rarely occur in the parotid gland. Histologic examination is most likely to show rows of palisading cells with a thickened basement membrane.

Myoepithelioma is a well-circumscribed benign tumor that arises from myoepithelial cells. This tumor is rare and typically affects the parotid gland or palate. Although it is clinically similar to pleomorphic adenoma, histologic examination shows spindle cells.

Sjögren’s syndrome is an autoimmune disease occurring most frequently in women and is characterized by destruction of the exocrine glands due to immune-related mechanisms. When associated with rheumatoid arthritis, it is known as secondary Sjögren’s syndrome. Unilateral or bilateral salivary gland swelling, frequently affecting the parotid gland, is present in 80% of patients with primary Sjögren’s syndrome and 40% of patients with secondary disease. Additional distinguishing findings include xerostomia, interstitial pneumonitis, Raynaud’s phenomenon, lymphadenopathy, purpura, pancreatitis, renal disease, and recurrent parotitis.

Warthin tumor, or papillary cystadenoma lymphomatosum, is a slow-growing multicystic mass most frequently seen in men between the ages of 40 and 70 years. It is almost always localized to the parotid gland and rarely occurs in the submandibular gland. Warthin tumors comprise 10% of all parotid tumors; 10% of affected patients have multicentric lesions, while another 10% have bilateral findings. Histologic examination shows a papillary epithelium containing lymphoid stroma that projects into cystic spaces.

References
1. Bradley PJ. Tumors of the salivary gland. In: Jones AS, Phillips DE, Hilgers FJ, eds. Diseases of the Head and Neck, Nose and Throat. London: Arnold; 1998:329-346.
2. Helliwell TR, Turnbull LS. Pathology of the head and neck. In: Jones AS, Phillips DE, Hilgers FJ, eds. Diseases of the Head and Neck, Nose and Throat. London: Arnold; 1998:24-42.
3. Rice DH. Diseases of the salivary glands – nonneoplastic. In: Bailey BJ, Calhoun KH, Deskin RW, et al, eds. Head and Neck Surgery – Otolaryngology. 2nd ed. Philadelphia, Pa: Lippincott-Raven; 1998;1:561-570.