Lymphoepithelial carcinoma of the parotid gland

Abstract

Primary lymphoepithelial carcinoma of the salivary glands is an exceptional oncological condition that predominantly emerges within the parotid gland. A significant prevalence of lymphoepithelial carcinoma has been reported in the Inuit population, along with an associated positive serology for Epstein-Barr virus in these endemic regions. In this paper, we present a case of primary lymphoepithelial carcinoma of the parotid gland in a 68-year-old female patient with a history of diabetes and hypertension residing in a non-endemic area. Histology plays a critical role in the definitive diagnosis, and confirming the primary origin of lymphoepithelial carcinoma after ruling out metastasis from undifferentiated nasopharyngeal carcinoma. The mainstay of treatment is a combination of surgical resection and adjuvant radiotherapy. Inoperable forms are typically managed with chemoradiotherapy.

Keywords: EBV neoplasms; Lymphoepithelial carcinoma; malignant parotid neoplasms.

Figure 1.

Magnetic resonance imaging (MRI) showing a right tumoral mass of the parotid. (a) T1-weighted sequence MRI frontal image showing the intracranial extension of the parotid tumor. (b) a T1-weighted sequence MRI axial image showing the infiltrating the right infra-temporal fossa by the parotid tumor.

Figure 2.

Poorly defined tumor nests and sheets separated by fibrosis and infiltrating between the residual entrapped salivary ducts (HE 100× magnification).

Figure 3.

Tumor cells with large atypical nuclei and poorly defined borders (syncytial appearance) intermixed with dense lymphoid stroma (HE 400× magnification).

Figure 4.

Lymphoepithelial carcinoma with lymphocytic cell infiltration in and around tumor nests; note the presence of follicles () (HE 200× magnification).

Figure 5.

(a) lymph node metastasis () of syncytial tumor sheets and accompanying lymphocytes (HE 200× magnification) (b) Epithelioid granuloma with Langerhans giant cells involving the lymph node (HE 200× magnification).

Figure 6.

(a) Tumor cells stain positive for pancytokeratin (×100 magnification) (b) Immunostaining for p63 shows diffuse nuclear positivity in tumor cells (×100 magnification) (c) Positive staining for epithelial membrane antigen in the majority of tumor cells (×100 magnification) (d) Negative immunoreactivity for CK7 in tumor cells (×100 magnification).

Figure 7.

(a) Negative staining of tumor cells for SMA (×200 magnification) (b) Negative staining of tumor cells for S-100 (×100 magnification) (c) High Ki 67 proliferation index (×200 magnification) (d) lymphocytes stain positive for CD20 with presence of follicles () (×100 magnification).

Figure 8.

Immunostaining for pancytokeratin highlighting the tumor cells in the lymph node metastasis (×100 magnification).