A 52-year-old woman presented to our Endocrinology Unit with a growing thyroid mass, which had enlarged so rapidly she had become unable to wear her motorcycle helmet in the weeks prior to her visit. She suffered from Hashimoto’s thyroiditis for which she was taking levothyroxine. There was no history of neck irradiation or family history of thyroid cancer. On examination, there was a large, firm thyroid nodule on the right side of the neck, without palpable cervical lymphadenopathy. TSH was 4.79 μU/mL with FT3 and FT4 within the reference range. Otherwise, there was only a mild thrombocytopenia. Thyroid ultrasonography showed a solid hypoechoic nodule in the right lobe of the gland, with significant internal vascularity and absence of calcifications (Figure ). FNA cytology with rapid on-site evaluation of the material adequacy showed that there were only atypical lymphoid cells with no thyrocytes and the specimens were considered suggestive of a lymphoproliferative disorder but insufficient to make a diagnosis, such that a CNB was scheduled for the following day.\nAfter checking the blood coagulation profile, the patient underwent a CNB, which allowed histological/morphological tissue analysis. This showed that normal thyrocytes were virtually all replaced by homogeneous medium-sized lymphocytes with scanty blue cytoplasm, round nuclei, coarse chromatin, and multiple small nucleoli. There were frequent mitotic figures and scattered macrophages ingesting apoptotic cells, giving to the tissue section the so-called ‘starry sky’ appearance (Fig. ). Overall, these features were consistent with the presence of a thyroid Burkitt’s lymphoma, and further investigations were ordered to confirm the diagnosis and evaluate the disease extent. A CT of chest and abdomen showed the 44x43x87 mm thyroid nodule with left tracheal deviation (Figure ) without other visible masses or lymph nodes. Bone marrow biopsy showed almost 100% lymphoid infiltration, consisting of a population of intermediate-sized blast-like cells, with prominent nucleoli, which were replacing all normal cells. These cells expressed CD10, CD20, and were negative for Bcl2, CD34, and TdT. Altogether these results led us to the final diagnosis of stage IV Burkitt’s lymphoma [].\nThe patient was admitted to our hospital’s Haematology Unit and was successfully treated with 3 cycles of Hyper-CVAD chemotherapy (cyclophosphamide, vincristine, doxorubicin and dexamethasone) completed in five months. The thyroid mass disappeared (Fig. ) and the platelets returned to baseline levels. At 60 months after diagnosis the patient is alive, and remains disease-free at regular follow-up.
A 64-year-old man with a history of hypothyroidism and proven Hashimoto's thyroiditis presented with painless progressive asymmetric enlargement of the thyroid gland. Laboratory evaluation revealed an elevated erythrocyte sedimentation rate (ESR), elevated thyroid peroxidase antibody titer of 850 U/mL (normal <30 U/mL), free triiodothyronine (FT3) 2.34, free thyroxine (FT4) 0.97, and thyroid stimulating hormone (TSH) level of 22.11. A contrast enhanced CT (CECT) exam of the neck revealed a large heterogeneous mass lesion predominantly involving the left lobe of thyroid and partly involving the isthmus and anterior part of right lobe. A needle biopsy from the thyroid mass revealed features of non-Hodgkin's lymphoma (DLBCL) with the tumor cells staining positive for CD20, negative for cytokeratin (CK) and having a high proliferative index (MIB-1) of 35-40%. 18F-FDG PET/CT was performed for staging. It revealed a large heterogeneous mass lesion predominantly involving the left lobe of thyroid and partly involving the isthmus and anterior part of right lobe with intense radiotracer uptake in the thyroid mass (SUVmax-18.7) with no other abnormal identifiable areas [Figure –]. The patient underwent four cycles of combination chemotherapy (rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone) and was reevaluated with 18F-FDG PET/CT. Post therapy 18F-FDG PET/CT [Figure –] done 6 weeks after completion of chemotherapy revealed significant decrease in the size of the enlarged thyroid gland associated with no significant FDG avidity (SUVmax-2.0) of the residual thyroid mass (arrow), suggestive of complete metabolic response. The patient is in complete remission at 18 month follow-up.