Lymphoepithelial like carcinoma of the anorectal junction, a rare entity associated with human papillomavirus rather than Epstein-Barr virus: a case report.

Background: The anal canal is a rare site for lymphoepithelial-like carcinoma (LELC) and has only been reported in two patients. LELC is an undifferentiated malignant neoplasm with lymphoid background that has been reported at various sites like salivary glands, breast etc. however very few cases have been reported in gastrointestinal (GI) tract. Case Description: We report the third case of a 58-year-old female who presented with a complaint of mild constipation and rectal pressure for eight months. Endoscopic ultrasound (EUS) showed a 0.8 cm nodule at the anorectal junction which was resected. Pathology showed LELC of the anorectal junction with diffuse positivity with p16 immunostaining. Polymerase chain reaction (PCR) for human papillomavirus (HPV) was positive for high-risk HPV-16, in situ hybridization (ISH) for Epstein-Barr virus (EBV)-encoded ribonucleic acid (EBER) was negative, and there was no loss of nuclear expression of mismatch repair (MMR) proteins. Patient subsequently received chemoradiation with no evidence of residual disease on restaging scans. Conclusions: The association between LELC of anal canal and viral agents such as HPV or EBV has yet to be established; however, all three cases reported to date, including our current case, were positive for high-risk HPV-16, suggesting a possible role of HPV in tumorigenesis of LELC of the anal canal.