A 21-year-old woman presented with a neck mass, heat intolerance, and palpitations for the previous 2 weeks. She was found to have a diffusely enlarged thyroid gland and tachycardia on examination. Thyroid-stimulating hormone, triiodothyronine (T3), and thyroxine (T4) were elevated, and radioactive iodine uptake study showed poor uptake. Subacute thyroiditis was treated with a nonsteroidal anti-inflammatory drug, which provided symptomatic relief. However, 3 weeks later she presented again with a progressively growing neck mass with new-onset dyspnea, dysphagia, and hoarseness of voice. On examination, her thyroid gland was diffusely enlarged with smooth borders, hard on palpation, and nontender. Computed tomography (CT) scan revealed a large thyroid mass with moderate airway narrowing and substernal extension (Figure). Ultrasound-guided needle biopsy was consistent with high-grade lymphoma with sheets of monomorphic lymphoid cells, mitotic figures, apoptotic cells, and tingle-body macrophages. On immunohistochemical staining, the lymphoma was positive for CD 10, CD 20, and BCL 6. Overnight, she was admitted for respiratory distress. She underwent incisional biopsy of the thyroid gland, which revealed Burkitt’s lymphoma with C-myc/immunoglobulin-H translocation.
A staging positron emission tomography/CT scan showed a 24.6 × 10 × 9.5-cm hypermetabolic mass extending from the suprahyoid to the diaphragm and hypermetabolic cervical lymph nodes. Bone marrow aspirate and cerebrospinal fluid analysis did not show any involvement. Serologic analysis for human immunodeficiency virus was negative. The patient was treated with a hyper-fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone regimen with rituximab chemotherapy. This was accompanied by intrathecal chemotherapy with methotrexate. She tolerated the regimen, and repeat imaging did not reveal any recurrence.
Malignancy accounts for approximately 5% to 10% of palpable thyroid nodules. The most common type is papillary thyroid cancer (80%-85%), followed by follicular carcinoma (8%-10%) and medullary thyroid cancer (5%-10%). Only approximately 1% to 5% of the cases are primary thyroid lymphomas. The most common histologic subtype of thyroid lymphomas is diffuse large B-cell lymphoma. The next most common is mucosa-associated lymphoid tissue lymphoma.2 Burkitt’s lymphoma is found in less than 1% of all primary thyroid lymphomas. In general, primary thyroid lymphoma is more common in the elderly, with a female-to-male ratio of 3:1. Hashimoto’s thyroiditis presents an increased risk for thyroid lymphoma, particularly mucosa-associated lymphoid tissue.
Most patients present with B-symptoms and laboratory evidence of tumor lysis. Bone marrow involvement is present up to 40% of the time, and leptomeningeal involvement may be present in up to 20% of adults at the time of diagnosis. It is essential that Burkitt’s lymphoma be evaluated as early as possible with adequate diagnostic tissue. Additional testing would include CT scan of the chest, abdomen, and pelvis, cerebrospinal fluid analysis, bone marrow biopsy, renal and liver function testing, and human immunodeficiency virus testing. Burkitt’s lymphoma cells are mature B cells, positive for CD19, CD20, CD22, and CD79a. They can also be positive for Bcl 6 and CD38, which are germinal center markers but are not specific for Burkitt’s lymphoma. A defining feature of Burkitt’s lymphoma is the presence of a translocation between c-myc and IgH genes, found in 80% of cases (t[8;14]) or between c-myc and the gene for the kappa or lambda light chain in the remaining 20% (t[2;8] or t[8;22], respectively).
Burkitt’s lymphoma is an exquisitely chemosensitive tumor. The role of surgery is only diagnostic. The addition of rituximab to hyper-fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone therapy has been shown to improve 3-year estimated survival, disease-free survival, and event-free survival.
To read this article in its entirety please visit our website.
-Divya Akshintala, MD, Bhanu T. Paturi, MD, Jijun Liu, MD, Vamsi K. Emani, MD
This article originally appeared in the September 2016 issue of The American Journal of Medicine.
