Abstract

Lymphoepithelial carcinoma (LEC) is a rare and poorly differentiated variant of squamous cell carcinoma characterized by a prominent reactive lymphoplasmacytic infiltrate. Morphologically, LEC resembles undifferentiated non-keratinizing nasopharyngeal carcinoma, which has a strong etiologic link to Epstein-Barr virus (EBV). Outside of the nasopharynx, a similar association with EBV is found in LEC of the salivary gland, sinonasal tract and the oral cavity. Whereas, lymphoepithelial-like carcinoma of the skin, which most frequently occurs in sun-exposed areas of the head and neck in elderly patients, is rarely associated with EBV. We report a case of a 74-year-old female who presented with a pink nodule with prominent telangiectasias on the right upper cutaneous lip, clinically suspicious for basal cell carcinoma, squamous cell carcinoma or an adnexal neoplasm. Initial biopsy of the lesion favoured the diagnosis of a poorly differentiated squamous cell carcinoma. Subsequent wide excision revealed the characteristic dense dermal inflammatory infiltrate admixed with large atypical epithelioid cells, consistent with a diagnosis of LEC. In-situ hybridization studies for EBV were positive in lesional tissue. The most common anatomic location for LEC in the head and neck is the salivary glands, with LEC of the oral cavity being very rare. The lip is an especially uncommon location for LEC, as is EBV-positivity at this site. LEC is an uncommon, but important diagnostic distinction to make from conventional squamous cell carcinoma, as the risk of metastasis is up to 70% in LEC, which may alter the treatment plan for these individuals.

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