T-Cell/Histiocyte-Rich Large B-Cell Lymphoma of the Thyroid

A 69-year-old woman was admitted to our hospital due to difficulty in breathing and thyroid tumor that had grown rapidly over a period of 1 month. The patient had a past history of chronic thyroiditis, which was diagnosed a year before on the basis of positive anti-thyroglobulin antibody and elevation of thyroid stimulating hormone with enlarged thyroid. The disease had been well controlled with levothyroxine supplementation. Computed tomography (CT) scan showed a diffuse and massive thyroid tumor narrowing the tracheal lumen (Figure 1a). No other tumors, lymphadenopathy, or hepatosplenomegaly were detected. There were no B symptoms. Due to the risk of sudden airway obstruction, urgent hemithyroidectomy and tracheal tube insertion were performed. Rapid frozen section diagnosis of the resected thyroid tumor suggested the possibility of lymphoma, and administration of prednisolone (PSL) was performed after the operation. The remaining thyroid tumor had reduced to some extent, and the patient’s general condition and respiratory state recovered well. Thorough pathological examination of the thyroid tumor revealed scattered neoplastic large B-lymphocytes, which were CD20+, CD79a+, CD5？, CD10？, CD15？, and CD30？, and surrounding abundant T-lymphocytes (CD3+) and histiocytes (CD68+) (Figure 1b？–？1f). In situ hybridization for Epstein-Barr virus-encoded RNA (EBER) was negative. According to the above findings, the diagnosis of T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) was established. Gallium scintigraphy showed increased gallium uptake in the thyroid with no other abnormal signals (Figure 1g). Bone marrow aspiration/biopsy revealed no infiltration of lymphoma cells. Serum lactate dehydrogenase was within the normal limits (217 IU/L), and soluble interleukin-2 receptor was slightly elevated (639 U/mL). The clinical stage was IE, and the patient was classified as being at low-intermediate risk according to the international prognostic index. She was successfully