The incidence of primary thyroid lymphoma in thyroid malignancies

We investigated the incidence of primary thyroid lymphoma in thyroid malignancies.

A total of 304 patients whose diagnoses were made as thyroid malignancies between January 1990 and December 2000 were retrospectively evaluated. Of these, primary thyroid lymphoma was documented in four female patients (1.3%; mean age 56.2 years; range 40 to 65 years). Findings from history, physical examination, blood biochemistry, thyroid hormone levels (T3, T4, TSH, thyroglobulin), thyroid scintigraphy, fine-needle aspiration biopsy, and cervical computed tomography (CT) were evaluated. Histopathologic results were evaluated according to the Revised European-American Lymphoma (REAL) classification.

The most common complaints on admission were a rapidly growing cervical mass, hoarseness, and dyspnea. In all the cases, thyroid hormone levels were normal, but thyroglobulin levels were 5 to 10 times as high as normal. Preoperative fine-needle aspiration was not helpful in two cases, whereas cervical CT was diagnostic. Pathologic diagnosis was diffuse large B cell lymphoma in all the cases. Postoperatively, three cases underwent chemotherapy and one case chemotherapy combined with radiotherapy. All the patients were operated on before 1997; one patient died, the remaining three patients have been under follow-up with no recurrences.

In our cases, treatment of localized thyroid lymphoma by surgery combined with chemotherapy or/and radiotherapy was effective.