Transthyretin related amyloid in a saphenous vein. Histological diagnosis in a patient undergoing coronary artery by-pass surgery

Abstract Amyloidosis is an under-diagnosed and challenging disease with clinical and etiologic heterogenicity, requiring amyloid sub-typing because of the distinctive prognostic and therapeutic impact. Transthyretin amyloidosis is more common in elderly patients and in such population undergoing cardiovascular surgery it could be worthy to be investigated. We herein describe an unusual case of transthyretin related vascular amyloidosis in an 81 y.o. man undergoing coronary artery by-pass surgery. Diagnosis was done after histology showed an intimal eccentric thickening in a remnant segment of the right saphenous vein that was harvested for grafting. Transthyretin related amyloidosis was demonstrated by histochemical Congo Red staining under polarized light and by immunohistochemistry, corresponding to the intimal thickening. The thorough histological analysis was crucial for the diagnosis of a previously unknown transthyretin related vascular amyloidosis.