Primary Intestinal-Type Adenocarcinoma of Tongue: A Case Report with Immunohistochemical and Molecular Profiles and Review of the Literature.

Primary lingual intestinal-type adenocarcinomas are extremely rare with only a few cases described. A case with immunohistochemical expression of Androgen Receptor (AR) which was treated solely by chemo-radiotherapy is reported herein. A 54-year-old male was referred with symptoms of fullness in his tongue. Clinical examination showed an asymmetry of the tongue with a hard mass palpable within the middle of the tongue. Biopsy showed intestinal-type adenocarcinoma. The tumour showed positive staining with cytokeratin 7, cytokeratin 20, CDX2, AR, β-catenin and was mismatch repair proteins (MMR) proficient. The molecular analysis did not show mutations in the KRAS, NRAS, BRAF and PIK3CA genes. The patient was treated with radiochemotherapy and is in remission 3.5 years after the diagnosis. This is the first case of intestinal-type tongue adenocarcinoma which showed AR expression and was treated solely with radical chemoradiotherapy.