Primary thyroid lymphoma: evaluation with CT.

The appearance of primary thyroid lymphoma on computed tomographic (CT) scans and clinical data for 15 patients were analyzed. The CT appearances were classified into three types: 12 patients (80%) had a solitary nodule (type 1), two (13%) had multiple nodules (type 2), and one (7%) had a diffuse goiter (type 3). In 47% of cases, both lobes were involved. The tumors had a strong tendency to compress (80%) or infiltrate (53%) the surrounding structures. The frequency of calcification (7%) or necrosis (7%) was low. Most patients (87%) had a rapidly enlarging thyroid mass, and six (40%) complained of symptoms from obstruction. All patients had coexistent Hashimoto thyroiditis. In 13 of 15 patients (87%), a highly probable diagnosis of thyroid lymphomas was determined with CT and clinical findings. A staging workup with CT and clinical findings confirmed at biopsy will allow appropriate therapy and may lead to improved prognosis for patients with this condition.