A Woman With a Palatal Swelling
Brent Accurso, DDS,
Carl Allen, DDS, MSD and
Guillermo Chacon, DDS
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THE CHALLENGE
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A 50-year-old woman noticed a swelling of approximately 18 months’ duration involving her left soft palate. She initially visited her family physician, who suggested that it might represent a ruptured blood vessel. When the lesion did not resolve in subsequent months, the family physician referred her to an otolaryngologist. Although unsure of the diagnosis, the otolaryngologist wanted to perform a biopsy. The patient then sought a second opinion from another otolaryngologist, and he referred her to an oral and maxillofacial pathologist (C.A.) for evaluation.
According to the patient, the lesion always had been asymptomatic, with no associated pain or paresthesia. The patient’s medical history was significant only for estrogen hormone replacement therapy. She had no history of tobacco use and no known allergies and had not undergone any surgeries or received radiation therapy to the head and neck. The clinical examination revealed a bluish-purple nodule with focal yellowish papules on her left soft palate (Figure 1
). The lesion measured approximately 1.2 centimeters, and it was firm and nontender on palpation.
Although a vascular lesion could not be ruled out entirely, the clinical features were most suggestive of a neoplastic process. For this reason, the oral and maxillofacial pathologist referred the patient to the Oral and Maxillofacial Surgery Clinic, College of Dentistry, The Ohio State University, Columbus, for an incisional biopsy. The histopathologic sections revealed a mixture of mucus-producing clear cells and epidermoid cells (Figures 2 and 3). A mild inflammatory infiltrate was present, and the lesional cells formed cystic spaces. The mucous cells contained abundant foamy cytoplasm, which stained positively with mucicarmine (Figure 4). The lesional cells did not exhibit significant mitotic activity or nuclear pleomorphism.
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Figure 2. Low-power photomicrograph revealing a neoplasm characterized by a lobular and cystic growth pattern within the connective tissue (hematoxylin-eosin, x40 magnification).
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Figure 3. High-power photomicrograph revealing a mixture of neoplastic mucous and epidermoid cells (hematoxylin-eosin, x200 magnification).
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Figure 4. Special stain for mucus, confirming the presence of mucous cells, which stain bright pink (mucicarmine, x200 magnification).
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Can you make the diagnosis?
- mucocele
- mucoepidermoid carcinoma
- pleomorphic adenoma
- hemangioma
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THE DIAGNOSIS
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B. mucoepidermoid carcinoma (low-grade)
Mucoepidermoid carcinoma is the most common malignant salivary gland tumor, making up approximately 30 percent of all salivary gland malignancies.1,2 It develops most frequently in the parotid gland, with approximately 60 percent of all mucoepidermoid carcinomas affecting this site. The palate is the most common location of tumors arising in the minor salivary glands.2,3 Mucoepidermoid carcinoma occurs across a wide age range, and it is the most prevalent salivary gland malignancy in children.1 A slight female predilection typically is reported.4,5 This tumor usually appears intraorally as a painless, slow-growing nodule.5 Parotid lesions tend to be high-grade, and patients have symptoms such as pain, facial nerve palsy and otorrhea.1,5 Intraoral tumors often are bluish-red in color and can be easily mistaken clinically for mucoceles or vascular lesions.1,3,5
The treatment and prognosis for patients diagnosed with a mucoepidermoid carcinoma are predicated on the location, clinical stage and histopathologic grade of the tumor. The most commonly used histopathologic grading system, developed by Auclair and colleagues in 1992,3 relies on the presence or absence of several microscopic features, including cystic structures, perineural invasion, necrosis, mitoses and anaplasia. Other suggested prognostic factors for mucoepidermoid carcinomas include the expression of Ki-67 and p27 proliferative markers.4,6
For the overwhelming majority of mucoepidermoid carcinomas, whether they occur in the major or minor salivary glands, the primary treatment modality is surgical resection.5,7 Clinicians usually reserve neck dissection for patients with clinical evidence of metastatic nodal disease.1,7 They generally consider low-grade mucoepidermoid carcinoma to be resistant to radiation therapy, although its use is warranted in patients with aggressive, high-grade tumors, patients with unclear surgical margins or patients with both.1,4,7 The majority of mucoepidermoid carcinomas encountered intraorally are low-grade, and investigators report survival rates exceeding 90 percent for patients who undergo wide surgical excision.1,5,7 However, survival rates for patients with high-grade tumors, or for those with metastases, are much lower, ranging from 20 to 45 percent.1,7
DIFFERENTIAL DIAGNOSIS
Pleomorphic adenoma.
Other lesions that clinicians should consider in the clinical differential diagnosis include pleomorphic adenoma, mucocele and hemangioma. Low- and intermediate-grade mucoepidermoid carcinomas commonly give the clinical impression of being pleomorphic adenoma, owing to their circumscription and relatively slow rate of growth.2 Pleomorphic adenoma is the most common of all salivary gland neoplasms, regardless of site.1,5 This tumor usually develops as a painless, slow-growing mass and has a slight female predilection.1,5 Histopathologically, these tumors can exhibit a variety of patterns, but they are composed of a mixture of neoplastic glandular epithelium and myoepithelial cells.1
Mucocele.
A mucocele is a common oral lesion, generally red-blue in color. More than 60 percent of these lesions occur on the lower lip.1 A mucocele develops when a salivary gland duct is disrupted and mucus accumulates in the surrounding tissue.1,5 Patients commonly report a history of having a recurrent swelling that ruptures, spilling its contents into the mouth.1 Histopathologically, a mucocele exhibits a pool of mucin surrounded by chronically inflamed granulation tissue. Minor salivary glands adjacent to the mucous deposit often are included in the biopsy specimen.1
Hemangioma.
A hemangioma is a common lesion that can develop anywhere on the body.2 The most common location of a hemangioma is the head and neck region, and 14 percent of all hemangiomas develop within the mouth.1,8 However, hemangiomas rarely are found on the hard palate, soft palate or uvula.2 This lesion commonly appears as a soft, painless mass that is red to blue in color, and it may or may not blanch under pressure.8 Histopathologically, a hemangioma exhibits a collection of endothelium-lined vessels that contain erythrocytes and are located in submucosal connective tissue.1,8
CONCLUSION
This case underscores the need for evaluation of oral lesions by health care providers with expertise related to this anatomical region. Although salivary gland malignancies are not common, the differential diagnosis for a bluish submucosal mass, particularly if the mass is located in the palate or retromolar region, should include lesions such as mucoepidermoid carcinoma.
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FOOTNOTES
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Dr. Accurso is a resident, Oral and Maxillofacial Pathology, College of Dentistry, The Ohio State University, Columbus.
Dr. Allen is a professor and the director of Oral and Maxillofacial Pathology, Section of Oral and Maxillofacial Surgery, Pathology, and Anesthesiology, College of Dentistry, The Ohio State University, 305 W. 12th Ave., Columbus, Ohio 43210, e-mail "allen.12{at}osu.edu". Address reprint requests to Dr. Allen.
At the time this article was written, Dr. Chacon was an associate professor, Section of Oral and Maxillofacial Surgery, Pathology, and Anesthesiology, College of Dentistry, The Ohio State University, Columbus. He currently is in private practice in Columbus, Ohio.
Disclosure. The authors did not report any disclosures.
Diagnostic Challenge is published in collaboration with the American Academy of Oral and Maxillofacial Pathology and the American Academy of Oral Medicine.
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REFERENCES
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- Neville BW, Damm D, Allen CM, Bouquot JE. Oral and Maxillofacial Pathology. 3rd ed. Philadelphia: Saunders; 2009:487–490.
- Barnes L. Surgical Pathology of the Head and Neck. 2nd ed. New York City: Dekker; 2001:690–697.
- Auclair PL, Goode RK, Ellis GL. Mucoepidermoid carcinoma of the intraoral salivary glands: evaluation and application of grading criteria in 143 cases. Cancer 1992;69(8):2021–2030.[Medline]
- Triantafillidou K, Dimitrakopoulos J, Iordanidis F, Koufogiannis D. Mucoepidermoid carcinoma of minor salivary glands: a clinical study of 16 cases and review of the literature. Oral Dis 2006;12(4):364–370.[Medline]
- Thompson LDR. Head and Neck Pathology. Philadelphia: Churchill Livingstone/Elsevier; 2006:325–332.
- Okabe M, Inagaki H, Murase T, Inoue M, Nagai N, Eimoto T. Prognostic significance of p27 and Ki-67 expression in mucoepidermoid carcinoma of the intraoral minor salivary gland. Mod Pathol 2001;14(10): 1008–1014.[Medline]
- Guzzo M, Andreola S, Sirizzotti G, Cantu G. Mucoepidermoid carcinoma of the salivary glands: clinicopathologic review of 108 patients treated at the National Cancer Institute of Milan. Ann Surg Oncol 2002;9(7):688–695.[Medline]
- Gnepp DR. Diagnostic Surgical Pathology of the Head and Neck. Philadelphia: Saunders; 2001:186–188.
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THE CHALLENGE
THE DIAGNOSIS
