Transthyretin amyloid goiter in a renal allograft recipient.

Amyloid deposition in the follicular, perifollicular blood vessels, and thyroid stroma can occur in systemic forms of amyloidosis, although diffuse enlargement of the thyroid is generally not present. Marked, widespread enlargement of the thyroid gland with amyloid deposits or amyloid goiter is a rare condition reported in association with primary and secondary amyloidosis but has not been described in association with transthyretin amyloid deposition. Senile transthyretin amyloidosis is primarily associated with amyloid deposits in the heart, while the familial forms of amyloidosis due to transthyretin gene mutations are associated with deposits of amyloid in multiple tissues, classically giving rise to polyneuropathy. In this report, we describe the findings of parathyroid and lymph node amyloid deposits and amyloid goiter with transthyretin reactivity in a recipient of a kidney allograft, reportedly for renal amyloidosis, initially assumed clinically to be due to inflammatory bowel disease-related secondary amyloid deposition. This case underscores the importance of routine immunohistochemical classification of amyloid deposits for accurate diagnosis and to guide clinical management decisions.