Sialadenoma papilliferum involving the nasopharynx.

A 15-year-old girl presented with a history of chronic nasal obstruction that had been unresponsive to nasal steroid therapy. Flexible endoscopic examination revealed that 4+ adenoid hypertrophy had obstructed the posterior choanae bilaterally (figure). The patient was scheduled for an adenoidectomy. Intraoperatively, adenoid tissue was found to be moderately hypertrophied. Additionally, a firm choanal mass was found and resected. Postoperatively, the patient did well and experienced no complications. Findings on histopathologic examination of the choanal lesion were consistent with sialadenoma papilliferum. A repeat nasopharyngoscopy 12 months postoperatively identified no evidence of recurrence.

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Sialadenoma papilliferum is a rare benign tumor of salivary gland origin; since its initial description in 1969, just over 50 cases have been reported in the literature. (1-3) These tumors arise predominantly from the oral cavity, and they have a proclivity for the palate; only 3 cases were previously identified in the nasopharynx. (4-7) The tumors usually arise from the ductal structures. They are regarded as analogs of the cutaneous syringocystadenoma papilliferum and are broadly categorized as adenomas. Overall, sialadenoma papilliferum accounts for less than 1% of both benign and malignant tumors of the minor salivary glands.

Gross examination usually reveals a well-circumscribed lesion that may be sessile or pedunculated. A cauliflower-like appearance demarcates the surface anatomy, and well-circumscribed tumor tissue extends below the surface, as in a verrucoid pattern.

Histologically, sialadenoma papilliferum is grouped with two other papillomatous salivary gland neoplasms: inverted ductal and intraductal papillomas. However, sialadenoma papilliferum has a more complex histology, demonstrating a biphasic growth pattern of exophytic and endophytic components. On light microscopy, it has a well-differentiated stratified squamous epithelium, which may have hyperkeratosis or parakeratosis. This epithelium merges with the submucosal glandular proliferation. Conversely, on light microscopy, inverted ductal and intraductal papillomas appear to arise from the excretory ducts near the mucosal surface, and their growth pattern is monophasic.

The differential diagnosis of sialadenoma papilliferum includes inverting ductal papilloma, intraductal papilloma, mucoepidermoid carcinoma, and peripheral papillary odontogenic tumor.

Simple excision is the treatment of choice. Recurrences have been reported, but they are usually secondary to persistent disease resulting from an incomplete primary excision. Follow-up includes endoscopy of the nasopharynx and interval computed tomography.

References

(1.) Abrams AM, Finck FM. Sialadenoma papilliferum. A previously unreported salivary gland tumor. Cancer 1969;24:1057-63.

(2.) van der Wal JE, van der Waal I. The rare sialadenoma papilliferum. Report of a case and review of the literature. Int J Oral Maxillofac Surg 1992;21:104-6.

(3.) Cleary KR, Batsakis JG. Sialadenoma papilliferum. Ann Otol Rhinol Laryngol 1990;99:756-8.

(4.) Markopoulos A, Kayavis I, Papanayotou P. Sialadenoma papilliferum of the oral cavity: Report of a case and literature review. J Oral Maxillofac Surg 1997;55:1181-4.

(5.) Asahina I, Abe M. Sialadenoma papilliferum of the hard palate: A case report and review of literature. J Oral Maxillofac Surg 1997; 55:1000-3.

(6.) Masi JD, Hoang KG, Sawyer R. Sialadenoma papilliferum of the adenoids in a 2-year-old child. Arch Pathol Lab Med 1986;110: 558-60.

(7.) Rennie JS, MacDonald DG. Critchlow HA. Sialadenoma papilliferum. A case report and review of the literature. Int J Oral Surg 1984;13:452-4.

From the Head and Neck Cancer Center, Cedars-Sinai Medical Center, Los Angeles.