The clinical presentation of lymphoma as a thyroid mass is rare. It has gradually become widely accepted that this entity often represents primary involvement of the gland comparable to that seen in other extranodal sites (1). The clinical picture described in several series is distinct and uniform, but treatment results have been variable (1–5). This paper reviews the radiotherapeutic experience with lymphoma of the thyroid of the Columbia-Presbyterian Medical Center. Materials and Analyses Clinical records were reviewed of the 11 cases of thyroid lymphoma seen from 1934 through 1967 at the Columbia-Presbyterian Medical Center. The diagnosis was histologically confirmed in all instances and reported as reticulum-cell sarcoma in 10 cases and giant follicular lymphosarcoma in one. In this last patient the postmortem diagnosis was also reticulum-cell sarcoma. The median age of the patients was fifty-nine years; the range was from thirty-seven to eighty-three years. Nine were females and two were males. The typical clinical presentation was that of a rapidly enlarging thyroid mass of two to three months duration. Only one patient had a pre-existing goiter. Approximately half the group had symptoms of pressure or invasion of neighboring structures, i.e., dyspnea, choking, dysphagia, or hoarseness. Physical examination in all cases revealed a hard, nontender mass which was often fixed. Clinically positive cervical lymph nodes were present at initial evaluation in 4 cases; an additional patient had involvement of the left axillary nodes. Vocal cord paralysis was present in 2 of the 5 with hoarseness. All patients were considered euthyroid after clinical and laboratory examinations. Thyroid antibody tests were performed in two; one had a weakly positive titer (1:32) and the other a highly positive titer (1:16,000), although neither patient proved to have Hashimoto's thyroiditis. An attempt at exogenous thyroid suppression of the mass was unsuccessful in 2 patients. Thyroid scintiscans were performed in 3 instances and correlated well with the extent of disease. A mass totally replacing thyroid tissue was represented as a “cold” area (Fig. 1), while patchy tumor infiltration was represented by heterogeneity of uptake (Fig. 2). Other routine blood studies were normal. Serum calcium, phosphorus, and alkaline phosphatase values were normal in the 4 patients studied. Chest radiographs were obtained in all patients, and 4 demonstrated tracheal displacement by a large thyroid mass. One patient had a widened superior mediastinum. All three esophagrams obtained showed displacement and narrowing. Intravenous urograms were obtained in the 4 recent cases and were normal. Open surgical exploration was performed in all patients. In 1 patient the disease was found to be confined within the capsule of the thyroid. In seven. local infiltration into fat, muscle, and adjacent structures was present (Table I).