Familial amyloidotic
polyneuropathy (FAP), a hereditary form of systemic
amyloidosis with clinically significant neuropathy and
cardiomyopathy, is caused by a genetic defect of the
transthyretin gene, which is mostly synthesized in the liver. Orthotopic
liver transplantation (OLT) is thought to eliminate the
amyloidogenic protein and currently is the only definitive treatment for this disorder. The aim of this study was to define the distribution and extent of
amyloid deposition in tissues from these patients and evaluate the suitability of the resected FAP livers for
transplantation into non-FAP patients. Surgical specimens from 14 patients removed at the time of OLT and autopsy tissues from 3 of the 14 were examined histologically using
hematoxylin and
eosin and
Congo red-stained sections. The extent of
amyloid deposits was evaluated, semiquantitatively graded from negative to marked, and correlated with
clinical course and patient outcome.
Amyloid deposits were consistently seen in hilar and vagus nerves. Liver lobular involvement was minimal in 1 and absent in the other 13 cases, with portal arterial
amyloid deposits seen in 7 cases. At autopsy, extensive
amyloid deposition in the heart was seen in all 3 cases with involvement of the conduction system. The extent of
amyloid deposition at OLT did not correlate with the duration of symptoms before OLT or patient outcome after OLT. In conclusion, liver parenchymal involvement in FAP is minimal, and these explants are suitable for grafting in non-FAP patients. The recipients of such grafts must be carefully observed for the development of any
amyloid-related disease, particularly
cardiomyopathy. Of the tissues removed at OLT, the histopathologic confirmation of FAP is most consistently made by the examination of hilar and vagus nerves.