Temporal artery involvement in AL amyloidosis: an important differential diagnosis for giant cell arteritis. A case report and literature review

Abstract

AL amyloidosis (AL) is a systemic disorder due to extracellular tissue deposition of amyloid fibrils, composed of immunoglobulin light chains. Since the description of AL involving temporal arteries in 1986, this disorder has been known as one of the differential diagnoses of giant cell arteritis (GCA). We encountered a case of an elderly female presenting with headache and tender and enlarged temporal arteries, that was pathologically diagnosed with temporal artery involvement of AL due to Bence–Jones-type MM. To our knowledge, this was the first case of AL with temporal artery involvement in Japan, that presented with GCA-like features. Literature review of AL cases with temporal artery involvement showed close similarity between these disorders, but suggested that vasculature involvement (extremity claudication, kidney or heart), macroglossia, carpal tunnel syndrome and normal or low (<0.5 mg/dL) CRP levels may predict AL rather than GCA. Physicians should keep in mind that AL involving temporal arteries can be a pitfall in the diagnosis of GCA, as seen in our and previous cases.

Keywords:

• AL amyloidosis
• giant cell arteritis
• multiple myeloma
• Bence–Jones protein
• temporal artery

Acknowledgements

We thank the distinguished internists, Kei Araki and Yoshiko Okigawa for their help for this study.

Patient consent

A written informed consent for this case report was obtained.

Conflict of interest

None.