Background: Massive amyloid deposition in the thyroid to the point of goiter formation is rare. Here we describe the clinical presentation and outcomes of five patients with amyloid goiter (radiographically confirmed goiter in the context of tissue-proven thyroid amyloidosis) encountered in the past 23 years at our institution.
Methods: Mayo Clinic archives were searched between 1987 and 2010 for a diagnosis of "thyroid amyloidosis," "amyloid deposits," "amyloid deposition," or "liquid chromatography consistent with amyloid." Inclusion criteria were symptomatic thyromegaly; tissue confirmation of thyroid enlarged by amyloid deposits; and radiologic confirmation of thyroid enlargement.
Results: Five patients were identified who met all inclusion criteria. Amyloid goiter etiology included both primary and secondary amyloidosis, and the goiters ranged in weight from 50 to 130 g each. Diagnosis was made by fine-needle aspiration biopsy with Congo red staining and, if needed, spectrophotometry. All five patients had histories of persistent hoarseness for several years before presentation with compressive symptoms referable to their enlarging thyroids, and all had some degree of thyroid dysfunction (both hypothyroidism and hyperthyroidism) by the end of our follow-up period, which ranged from 5 months to 13 years. Two patients underwent surgical interventions, two were managed conservatively, and in one, the goiter shrank after systemic therapy for amyloidosis.
Conclusions: Our clinical observations suggest slower goiter progression and a higher prevalence of thyroid dysfunction than previously thought.