Difficulties in the Diagnosis of Fibrinogen Aα-Chain Amyloidosis-Literature Review and Case Report of a Patient After Kidney Transplantation.

BACKGROUND: Amyloidosis is a very heterogeneous disease. Correct diagnosis is extremely important because of the various treatment options for different types of amyloidosis. This study presents a case report and literature review of the misdiagnosis of fibrinogen Aα-chain amyloidosis (AFib amyloidosis).

CASE PRESENTATION: We report a 65-year-old man diagnosed with proteinuria in 2009. The kidney biopsy revealed the presence of Congo red-stained amyloid deposits. During differential diagnosis, amyloid deposits were discovered in adipose tissue and gingiva. Bone marrow trephine biopsy showed a predominance of lambda chains presenting plasmocytes. Based on performed medical examination, light chain amyloidosis was identified. Therefore, the patient received high-dose melphalan and underwent successful autologous peripheral blood stem cell transplantation. However, proteinuria, worsening of the kidneys' function, and incorrect levels of free light chains were still observed. In 2019, due to continuous treatment failure, a previously acquired kidney biopsy was examined by mass spectrometry, and numerous fibrinogen deposits were identified. Recommended DNA analysis revealed that the patient had AFib amyloidosis. Therefore, chemotherapy treatment was abandoned, and successful kidney transplantation was performed.

CONCLUSION: Today, it is essential for medical practitioners to remember the possibility of rare and hereditary types of amyloidosis. There are multiple cases where a diagnosis was wrong or delayed because of the atypical course of the disease, the coexistence of another disease, and the rarity of AFib amyloidosis, and all of these reasons may result in the wrong treatment that will delay the right therapy. However, with the new, more precise diagnostics methods, such situations will become rare.