Primary Malignant Lymphoma of the Thyroid

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Primary Malignant Lymphoma of the Thyroid

Case 96-3

 

History/Physical Findings:

A 62-year-old white woman presented with stridor due to a neck mass which was clinically suspicious for multinodular goiter. The patient was placed on Synthroid, however, the gland continued to enlarge over the course of three weeks as evidenced by increased stridor and dysphagia. She reported a 40 pound weight loss over the previous six months. Additional symptoms included chronic fatigue and occasional chills. She reported a 36 pack year history of tobacco use.

Thyroid studies performed at the initial consultation included: total thyroxine 19.0 ug/dL (normal range=4.5-10.9 ug/dL), TSH 0.04 uIU/mL (normal range = 0.4-6.0 uIU/mL) and thyroid hormone uptake 27% (normal range = 25-35%).

Due to the compression of the trachea a total thyroidectomy was performed. The gland measured 14 x 12 x 7 cm and weighed 460 grams.

 

thyroid1 The entire gland is shown, with asymmetrical enlargement of the right side.

 

thyroid2 The cut section of the right lobe showed a necrotic center surrounded by tan fleshy tissue.
thyroid3 thyroid4

 

  thyroid5 thyroid6

 

What is your diagnosis?

Discussion:

H&E stained sections are shown identifying a diffuse large lymphocytic infiltrate with rare residual thyroid follicles identified. A B cell marker, CD 20 (L26), marked the lymphocytes. The T cell markers, CD 3 and CD 45RO, were negative. Kappa and lambda were non-contributory. A cytokeratin cocktail highlighted the residual thyroid follicles but the lymphocytes were negative.

 

Primary lymphoma of the thyroid consists of approximately 8 percent of all thyroid malignancies whereas involvement of the thyroid by systemic lymphoma or leukemia can be found in approximately 10 % of cases.

 

Primary thyroid lymphoma is usually seen in patients in their sixties with a female to male ratio varying from 2:1 to 8:1. The duration of symptoms is usually short and include hoarseness, dysphagia and or dyspnea. These symptoms are usually due to extra-thyroid extension. Most patients are euthyroid.

 

Upon gross examination, the tumor presents as a solid mass with a homogenous bulging surface exhibiting the characteristic fish-flesh appearance. The interface between normal gland and tumor is usually ill-defined. Necrosis and hemorrhage are unusual findings in lymphomas of the thyroid.

 

The majority of primary thyroid lymphomas are non-Hodgkins lymphomas and are usually large cell lymphomas with a B cell phenotype. The second most common lymphoma is the immunoblastic type although poorly differentiated and intermediate types have also been reported.

 

In approximately 80% of the cases of thyroid lymphoma the residual uninvolved gland exhibits features of autoimmune thyroiditis (Hashimotos's or lymphocytic type). It is speculated that the presence of thyroiditis predisposes the patient to lymphoma as opposed to the thyroiditis occurring after the lymphoma. However, the percentage of patients with thyroiditis who develop lymphoma is low.

 


Diagnosis:

Primary malignant lymphoma of the thyroid


References:

  • Shimaoka K, Sokal JE, Pickren JW. Metastatic neoplasms in the thyroid gland. Cancer 1962; 15:557-65.

     

  • Heimann R, Vannineuse A, DeSloover C, Dor P. Malignant lymphomas and undifferentiated small cell carcinoma of the thyroid: a clinicopathological review in light of the Kiel classification for malignant lymphomas. Histopathology 1978, 2:201-213.

     

  • Rosai J, Carcangiu ML, Delellis RA. Tumors of the Thyroid Gland. Atlas of Tumor Pathology, Third Series Fascicle 5, pp267-278. Published by the Armed Forces Institute of Pathology, Washington DC.

Contributors:

David C. Winston, M.D., PhD
Department of Pathology
University of Virginia Health System

Donald J. Innes, Jr., M.D.
Department of Pathology
University of Virginia Health System

 

Questions should be addressed to dji@virginia.edu