Amyloid goiter. A clinicopathologic study of 14 cases and review of the literature.

The authors report the clinicopathologic features of 14 cases of amyloid goiter (AG). Eleven patients were males and three females with ages ranging from 23 to 75 years (median, 54 years). Eight patients had secondary amyloidosis and six had primary amyloidosis. Nine cases were identified at autopsy. In symptomatic patients (n = 5), the clinical presentation included a nontender, rapidly enlarging neck mass with associated dysphagia, dyspnea or hoarseness. Clinical or laboratory evaluation failed to detect evidence of thyroid dysfunction. The histologic appearance of the thyroid predominantly consisted of diffuse amyloid deposition surrounding thyroid follicles. In two cases, a nodular pattern of amyloid deposition was seen resulting in compression and distortion of the follicular architecture. Areas of mature adipose tissue and focal lymphocytic thyroiditis with or without foreign-body type-giant cells were seen in approximately one third of the cases. Confirmation of amyloid was made by the presence of congophilia and apple-green birefringence under polarized-light microscopy. Immunohistochemical evaluation demonstrated the presence of amyloid A immunoreactivity. No Immunoreactivity was seen with calcitonin or thyroglobulin. Fine-needle aspiration may facilitate the diagnosis, as occurred in one the patients. In symptomatic patients, thyroidectomy is warranted to alleviate pressure symptoms.