Necrotizing Sialometaplasia of the Hard Palate: A Rare Entity of Dilemma on Cytology, Confirmatory on Histopathology

Non-Ulcerated and Ulcerated Necrotizing Sialometaplasia: Report of an Additional Case and Literature Review

Necrotizing sialometaplasia (NS) is a rare, self-limiting, necrotizing inflammatory lesion, often involving the minor salivary glands of the palate. NS occurs often in men (60%) older than 45 years. Commonly, it presents as an ulcerative lesion, measuring 1 to 3 cm in diameter, with an evolution time of a few weeks or days, simulating malignancy. However, in some instances, the mucosal surface is intact, thus emphasizing the importance of considering NS in the differential diagnosis of oral ulcerative and non-ulcerative lesions. To date, 12 cases of non-ulcerated NS in the palate have been reported. Here, we report a 50-year-old male patient who presented a non-ulcerated, asymptomatic, nodular swelling 3 months ago, located on the hard palate, clinically suggesting salivary gland tumor or lymphoproliferative disorder. After biopsy, a diagnosis of non-ulcerated NS was established. After 4 weeks, the lesion evolved with complete resolution. After literature review, notably, unlike ulcerated NS, the non-ulcerated NS affected patients a decade younger (33 years vs. 45 years), with marked female predilection (83% vs. 40%) and not uncommon bilateral presentation (33% vs. 10%). NS should be considered in the differential diagnosis of ulcerative and non-ulcerative lesions affecting the palate.

Salivary gland neoplasms in small biopsies and fine needle aspirations

Salivary gland neoplasms are rare and represent a diverse group of head and neck tumors. Their diagnosis in limited cellularity specimens can be challenging as many of these have overlapping clinical, radiological presentation, and pathologic features. Fine needle aspiration and/or core biopsies are more of a norm than rarity to be performed preoperatively to provide invaluable information that can guide clinical management including surgery. Even though these limited specimens may not always provide a definitive diagnosis; they have high sensitivity in confirming primary neoplasia, assessing the tumor grade, and ruling out non-surgical disease. An algorithmic pattern based approach can help narrow the differential diagnosis; leading to a definitive diagnosis with the help of specific ancillary studies.

Non-ulcerated necrotizing sialometaplasia may mimic a salivary gland tumor

Necrotizing sialometaplasia (NS) is a benign, self-limiting inflammatory entity that mainly affects the minor salivary glands located in the hard palate. Classically, NS is characterized as a nodule that evolves to a central ulcer. The most widely recognized triggering factor is an ischemic event. The diagnosis becomes a challenge in non-ulcerated NS cases which is essential to rule out the possibility of salivary gland tumors, especially the malignant ones. Here, we presented a case of a 32-year-old male patient with a 1-month complaint of a painful, slightly elevated erythematous area on the hard palate. Incisional biopsy was performed, and NS was diagnosed based on histopathological and immunohistochemical analyses. Clinicians should be aware of and consider NS as a differential diagnosis of minor salivary gland tumors, particularly when it presents as a non-ulcerated clinical aspect.

[Immunohistochemical diagnosis of necrotizing sialometaplasia]

The article presents a clinical case of an immunohistochemical study of a rare disease: necrotizing sialometaplasia in the hard palate. Due to the complexity of the differential diagnosis between necrotizing sialometaplasia and squamous cell carcinoma, an immunohistochemical method was used with antibodies to proteins Ki-67, P53, P63 and cytokeratins-7 and Immunohistochemical study established low proliferative activity of glandular cells in excretory ducts and metaplastic squamous epithelium for Ki-67 protein, significant expression of protein P63 was detected both in the ductal epithelium nuclei and in metaplastic areas and expression of the mutant protein P53 was approximately absent. Marked expression of cytokeratin-7 in the ducts cells and weak expression in necrotic acini of the glands and metaplastic epithelium was noted. It was shown that cytokeratin-15 homogeneously stains the peripheral zone of metaplastic epithelium, which is characteristic of a benign lesion. Thus, the panel of antibodies to proteins Ki-67, P53 and cytokeratins-7 and 15 allows to verify necrotizing sialometaplasia.