The first reported case of primary extranodal counterpart of follicular T-cell lymphoma of submandibular gland.

This is the first reported case of follicular T-cell lymphoma (FTCL) that primarily developed in the extranodal site of the right submandibular gland. An 86-year-old man was detected with a right cervical mass suspected to be malignant lymphoma during his physical examination. Imaging studies revealed that the mass was a submandibular gland tumor. The tumor was excised for diagnosis and treatment. Pathologically, the tumor was composed of densely aggregated lymphocytes with a follicular growth pattern. The immunohistochemical investigation showed that the lymphoma cells expressed CD3, CD4, programmed cell death protein 1, BCL6, chemokine (C-X-C motif) ligand 13, and BCL2. Staining of the follicular dendritic cell revealed its meshwork structure limited in the germinal center. Monoclonal rearrangement of the T-cell receptor was detected using polymerase chain reaction. These findings are consistent with the characteristics of FTCL. Here, we describe the first reported case of extranodal counterpart of FTCL of the submandibular gland. Accumulation and investigation of such extranodal cases is essential.