Endocrine Abstracts

Introduction

Primary thyroid lymphoma (PTL) is a rare affection that represents only 1% to 5% of thyroid malignancies and 1% to 2% of extranodal lymphomas. It involves by definition only the thyroid gland and adjacent neck lymph nodes, at diagnosis.

Case presentation:

A 65-year-old woman with a controlled Hashimoto’s thyroiditis presented with a 12-month history of painless neck swelling, recently increasing in size and occasionally causing hoarseness. Physical examination showed a large no tender nodular goiter, anterior cervical adenopathies and a positive Pemberton’s sign. Cervical ultrasound revealed a 6 cm left thyroid nodule EU-TIRADS 5. Fine needle aspiration was suggestive of a high-grade lymphoma. Thyroid and cervical lymph node biopsies later confirmed the diagnosis of diffuse large B-cell lymphoma (DLBCL). On immunohistochemical staining, the tumor cells were positive for CD20, CD10, Bc16 and Ki67 (70%). No other dissemination was found on the thoracic-Abdominal-Pelvic scan nor the bone marrow biopsy. So the lymphoma was classified IIE on the Ann Arbor classification. The chemotherapy was delayed for 2 months because of the patient’s Covid-19 infection, she then was started on an 8-cycle chemotherapy regimen including cyclophosphamide, adriamycin, vincristine and prednisone in association with rituximab. Adjuvant radiotherapy is scheduled.

Discussion and conclusions

Similarly to our case report, PTL is usually observed in middle to older aged females, but it commonly has a faster progression. DLBCLs account for 50 to 80% while mucosa-associated lymphoid tissue lymphoma, presents 20–30% of all PTLs. Autoimmune chronic lymphocytic thyroiditis is a well-established risk factor with an 80-fold risk compared to individuals without Hashimoto’s thyroiditis, which suggests a pathogenesis related to chronic inflammatory stimulation. Our Patient has a low intermediate International Prognostic Index (IPI). Prognostic factors include age, Size of the tumor, stage of the disease, the presence of symptoms due to B-cells, levels of LDH. The conventional chemotherapeutic regimen for PTL includes cyclophosphamide, doxorubicin, vincristine, and prednisone. Rituximab, a monoclonal antibody anti-CD20, represented an advance in the treatment of DLBCL. Currently, most authors support combined chemo-radiation therapy since it ensures a better outcome for five-year overall survival.