Concurrent wild‐type transthyretin amyloidosis and psoriasis vulgaris in an elderly man

Concurrent wild-type transthyretin amyloidosis and psoriasis vulgaris in an elderly manSystemic amyloidosis encompasses several types, including lightchain (AL) amyloidosis, inflammatory (AA) amyloidosis, and transthyretin amyloidosis (ATTR).The last is subdivided into a hereditary form (ATTRv) and a wild-type form (ATTRwt). 1 Because psoriasis vulgaris (PV) is an inflammatory keratinization disorder, there have been occasional reports of AA amyloidosis associated with psoriasis.However, few reports have addressed ATTR with PV.A 90-year-old male patient's history included longstanding PV, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, and bilateral macular degeneration with glaucoma.There was no family history of amyloid-related diseases.He presented with NYHA class II heart failure symptoms and was on diuretics and cardioprotective medications.Blood tests showed elevated | e 547 LETTER TO THE EDITOR M protein nor Bence-Jones protein, ruling out multiple myeloma and other monoclonal gammopathies.An examination showed characteristic PV lesions (Figure 1b-d).No cutaneous signs suggestive of cutaneous amyloidosis, papules, or nodules were observed.Skin biopsies from a psoriatic lesion and from two randomly selected non-lesional abdominal sites demonstrated amyloid deposits in direct fast scarlet staining, which were subsequently confirmed by anti-transthyretin antibody immunohistochemistry to be transthyretin deposits (Figure 1e,f).Immunohistochemical staining was negative for serum amyloid A and for immunoglobulin kappa and lambda light chains.Following approval from the medical ethics committee of the Nagoya University Graduate School of Medicine and informed consent, variant analysis did not reveal pathogenic variants in TTR, confirming the diagnosis of ATTRwt.In autopsy studies of systemic amyloidosis, amyloid deposition in the heart was found in 22%-25% of people over age 80. 2 Despite the absence of overt skin manifestations, the present case highlights the importance of considering ATTRwt in elderly patients who show suggestive systemic findings.A skin biopsy is considered a valuable diagnostic tool in such cases, especially for patients who are unable to undergo cardiac biopsy.The association between PV and ATTRwt is not well-documented.The prevalence of PV in the Japanese population is 0.34%, 3 and reports from overseas suggest a prevalence of 0.46% for ATTRwt in people aged 65-90 years. 4The coexistence of ATTRwt and PV is rare but statistically possible, as ATTRwt prevalence increases with age.Transthyretin remains stable as a tetramer, but with age, it dissociates into monomers, promoting amyloid fibril formation. 5This may result from post-translational changes or reduced hepatic chaperone activity, impairing the liver's ability to prevent misfolding. 5However, the interaction between psoriatic inflammation and ATTR in the skin remains uncertain.Severe psoriasis is associated with an elevated risk of cardiovascular events also due to systemic inflammation and metabolic abnormalities.The present case suggests the need for further research on the potential relationship between ATTRwt and PV.