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

Amyloidosis is an underdiagnosed and challenging disease with clinical and etiologic heterogenicity, requiring amyloid subtyping 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-year-old man undergoing coronary artery bypass surgery. Diagnosis 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. •Amyloidosis is an under-diagnosed and clinically heterogeneous disease•Amyloid sub-typing is mandatory because of distinctive prognosis and treatment•Transthyretin-related amyloidosis is more common in elderly patients•Histology may be crucial for diagnosing previously unknown vascular amyloidosis In a saphenous vein harvested for coronary artery bypass surgery, an eccentric intimal thickening that was evidenced by routine histology (A, E; hematoxlyin–eosin staining) is shown to correspond to amyloid deposits by Congo Red histochemical staining (B, F with apple green birefringence under polarized light in C, G) and to be strongly immunoreactive for transthyretin (D, H). [Display omitted]