Intraoral Salivary Duct Cyst: Clinical and Histopathologic Features of 177 Cases

Abstract

The salivary duct cyst (SDC) is a reactive ductal ectasia most frequently seen in major salivary glands, and likely caused by obstruction. The aim of this study is to define the clinical and histopathologic spectrum of intraoral SDCs. Cases were retrieved from the archives of Harvard School of Dental Medicine/StrataDx, Inc. from January 2012 to August 2014. There were 177 cases of which 103 (58.2%) occurred in females, with a median age of 56 (range 2-95). Approximately half of cases (45.8%) presented in the area of the buccal mucosa, lower lip mucosa, or mandibular vestibule, and 23.2% presented in the floor of mouth. SDCs were lined at least focally by 1-2 layers of cuboidal/columnar epithelium in 85.3% of cases and showed varying degrees of metaplasia (oncocytic, mucous cell, squamous, ciliated, apocrine-like) in 68.4% of cases. Intraluminal mucous stasis was present in 41.8% of SDCs, incipient calcification was present within 4.5% of SDCs, and chronic obstructive sialadenitis was seen in 90.2% of cases. No cysts showed adenomatous ductal proliferations or true papillary structures with fibrovascular cores, although 41.2% exhibited reactive undulation of cyst lining. Thirty-nine 'papillary oncocytic cystadenoma-like' SDCs (22.0%) demonstrated complete oncocytic metaplasia and marked undulation. An additional seven such cysts (4.0%) had a 'Warthin tumor-like' lymphoplasmacytic infiltrate. Intraoral SDCs occur most commonly in the sixth decade of life in locations distinct from extravasation mucoceles, likely secondary to intraluminal obstruction. SDCs show diverse histopathology and certain phenotypic variants may be mistaken for papillary oncocytic cystadenoma or Warthin tumor.

Challenges in Minor Salivary Gland Biopsies: A Practical Approach to Problematic Histologic Patterns

“…The non-neoplastic lesions that most closely overlap with true tumors are salivary duct cysts, also known as mucous retention cysts. These cysts, which are thought to represent dilation of the salivary duct system secondary to obstruction, can demonstrate a wide range of metaplastic changes, most notably including mucinous metaplasia with well-developed goblet cell formation [46]. Importantly, even though a significant subset of salivary duct cysts can show irregularities and undulations of their walls, the absence of complex glandular architecture or infiltrative growth can help distinguish them from MEC (Fig.…”

Diagnostic Approach to Fine Needle Aspirations of Cystic Lesions of the Salivary Gland

“…Unlike a mucocele that is surrounded by granulation tissue and/or fibrosis, a salivary duct cyst is lined by epithelium (true cyst). They are lined by 1-2 layers of cuboidal/columnar epithelium showing varying types of metaplasia (oncocytic, mucous cell, squamous, sebaceous, ciliated, apocrine-like) [23]. Papillary proliferation may rarely be seen, and should be separated from a cystadenoma [24].…”

Case of a Large Oropharyngeal Cyst

“…Intraoral salivary duct cysts are acquired masses due to the obstruction of a major or minor salivary gland. They are typically characterized by columnar or cuboidal epithelium, though they may show squamous metaplasia [4]. Imaging in our patient did not show any obstructions or abnormalities of the salivary glands, making this diagnosis less plausible.…”