T-Cell/Histiocyte-Rich Large B-Cell Lymphoma: Report of the First Case in the Mandible.

T-cell/histiocyte-rich large B-cell lymphoma (THRBCL) is an uncommon subtype of non-Hodgkin's lymphoma. It is a predominant nodal neoplasm; however, extranodal sites, such as the spleen, liver and bone marrow, can be involved at diagnosis. However, only one case of primary THRLBCL in the jaws have been reported. We herein describe a 29-year-old female patient who presented with a swelling of the right mandible that had grown rapidly over the previous 2 months. Periapical and panoramic radiographs showed a multilocular osteolytic lesion located in the mandibular periapical region of the canine and premolar teeth and molar region. Preoperative examination and incisional biopsy were performed. Immunohistochemistry was applied to confirm the diagnosis of THRBCL in the jaw. The treatment consisted of CHOP therapy and radiotherapy. After complete tumor remission following initial treatment, additional sites of the disease appeared in the lung, abdomen and long bones. The patient died within 2 months. THRLBCL is an uncommon and aggressive malignant neoplasm that can involve the jaws, mimicking a periapical disease.