Thyroid diffuse large B cell lymphoma (DLBCL) following thyroid medullary cancer: long-term complete remission with R-CHOP therapy

Abstract

Dear Editor, We present here a case of thyroid diffuse large B cell lymphoma (DLBCL) arising on the background of thyroid medullary cancer, which was treated with thyroid lobectomy 10 years ago, and highlight its excellent response to treatment with rituximab-based CHOP chemotherapy (RCHOP). To our knowledge, this is the first case of primary thyroid lymphoma following thyroid medullary cancer. A 63-year-old Chinese womanwas admitted to our hospital with the complaints of neck mass, slight cough and dyspnea for 2 weeks in Aug 2005. She had a previous history of thyroid mass in the right lobe and received lobectomy 10 years ago. At that time, histopathological examination of the biopsy specimen from the thyroid mass was reported as thyroid medullary cancer (Fig. 1a). Immunohistochemical and special stainings displayed Cal (+), CK (+), Syn (+), TG (−), EMA (−), Congo red (+) and NSE (+) (Fig. 1b), which were consistent with the diagnostic features of thyroid medullary cancer. She had not undergone any chemotherapy or radiotherapy, and kept in a good condition after the surgical operation. Regular examinations including thyroid function tests and ultrasonic scan for thyroid showed no abnormality. Two weeks before admission, she found a mass up to 6 cm in diameter in the thyroid, with slight cough and dyspnea. Physical examination showed III grade enlargement in thyroid with deviation of trachea. No lymphadenopathy and hepatosplenomegaly was found. Laboratory examinations revealed that, blood cell counts, urine routine, stool routine, serum electrolytes, liver function, and renal function were within normal limits; serum lactate dehydrogenase (LDH) was 360 u/L, serum β2-microglobulin (BMG), immunoglobulin, and calcitonin were normal. Thyroid functional profile included a T3 of 0.89 nmol/L (0.7–2.7), T4 of 73.6 nmol/L (58.1–164.8), FT3 of 1.80 pmol/L (2.1– 6.2), FrT4 of 13.7 pmol/L (9.0–23.9), TSH of 3.8 mIU/L (0.35–5.5). The anti-microsomal antibody (MCA) and thyroglobulin antibody (TGA) were detected as negative titers with a radio-immunity (RI) method. Bone marrow smear showed normal cellular morphology and cellular ratio. A computerized tomography (CT) scan of the neck showed a mass in thyroid with trachea compressed. Chest and abdomen CT showed no lymph node or organ involvement. With the dyspnea progressed, a tracheal intubation subsequently a surgical operation was performed. The surgery was palliative just for relieving the airway obstruction and mass biopsy. Histopathological examination from thyroid mass biopsy showed diffuse proliferation of lymphoma cells with large nuclei (Fig. 2a). Immunohistochemically staining indicated MUM1(−), CD45R0(−), EMA(−), LCK(−), CaL(−), TG(−), LCA(++), Bcl-6(+), CD10 (+), and CD20(++) (Fig. 2b). A diagnosis of diffuse large B cell lymphoma (DLBCL), stage IE, was made. The international prognostic index (IPI) portrayed a lowintermediate risk. The patient was treated with CHOP (cyclophosphamide, doxorubicin, vincristin, and prednisolone) combined with rituximab (MabThera). After six courses of R-CHOP regimen, the mass in thyroid completely disappeared and she is still in complete remission after a 34 month follow-up. Non-Hodgkin’s lymphoma (NHL) of the thyroid gland is uncommon, accounting for only 1–5% of all thyroid malignancies, and classified as non-epithelial thyroid tumors [1–3]. In this report, we present the case that developed a DLBCL in the thyroid site where a thyroid Ann Hematol (2009) 88:701–702 DOI 10.1007/s00277-008-0639-9