Squamous Cell Carcinoma of Parotid Gland Associated with Concurrent Lymphoepithelial Cysts and Lymphoepithelial Lesion: Case Report and Proposed Histogenesis

Abstract

Lymphoepithelial cyst and lymphoepithelial lesion have similar histologic features and an affinity for the parotid gland. Though considered as different entities, both conditions arise from heterotopic salivary epithelial rests or inclusions in intra-or peri-parotid lymph nodes. We present a case of squamous cell carcinoma of parotid gland associated with concurrent lymphoepithelial cyst and lymphoepithelial lesion in a patient who was not infected with human immunodeficiency virus. We propose that lymphoepithelial cyst and lymphoepithelial lesion have a similar histogenesis.

Clinicopathological and immunohistochemical features of the oral lymphoepithelial cyst: A multicenter study

“…Lymphoepithelial cysts have been reported in glandular tissues, such as the parotid gland and pancreas. Lesions of the parotid gland seem to develop from sialadenitis, followed by the cystic dilatation of ducts for the full development of the cyst, mechanical obstruction of salivary ducts due to exuberant lymphoid infiltration, or the proliferation of epithelial rests or inclusions within the parotid lymphoid tissue under certain antigenic or mechanical stimuli . Similarly, the inclusion of epithelium in a peripancreatic lymph node, squamous metaplasia from an obstructed and enlarged intrapancreatic duct, or a misplaced branchial cleft during embryogenesis seems to be involved in the development of lymphoepithelial cysts in the pancreas .…”

“…or the proliferation of epithelial rests or inclusions within the parotid lymphoid tissue under certain antigenic or mechanical stimuli. 13 Similarly, the inclusion of epithelium in a peripancreatic lymph node, squamous metaplasia from an obstructed and enlarged intrapancreatic duct, or a misplaced branchial cleft during embryogenesis seems to be involved in the development of lymphoepithelial cysts in the pancreas. 19,20 Despite the origin of lymphoepithelial cysts in different organs, the pathological findings are similar: a cavity filled with yellowish-white material, lined with squamous epithelium, and surrounded by lymphoid tissue that may be organized into lymphoid overlying mucosa found herein has been reported elsewhere.…”

“…Thus, although lymphocytic infiltrate is a prominent microscopic finding of OLEC, its cell composition has not been characterized and no previous studies have described the immunohistochemical features . In contrast, parotid lymphoepithelial cysts have been largely described …”

“…3,9 In contrast, parotid lymphoepithelial cysts have been largely described. [10][11][12][13] There is no consensus on the pathogenesis of OLEC. Lingual and palatine tonsils are lymphoid-rich regions of the oral cavity and, along with the nasopharyngeal and tubal tonsils, comprise Waldeyer's ring.…”

MRI findings of sporadic/simple lymphoepithelial cyst of the parotid gland

“…Benign lymphoepithelial lesions have an affinity for the parotid gland and arise from heterotopic salivary epithelial rests or inclusions in the intra- or periparotid lymph nodes. 1 These lesions cover a spectrum ranging from BLEC to lymphoepithelial sialadenitis of Sjögren syndrome and both HIV-related and HIV-unrelated cystic lymphoid hyperplasia. 2 They present a common microscopic appearance characterized by epimyoepithelial islands and/or epithelium-lined cysts in a lymphoid stroma.…”