Waldenström's macroglobulinemia associated with serum amyloid A protein amyloidosis: pitfalls in diagnosis and successful treatment with melphalan-based autologous stem cell transplant

Intestinal Reactive Amyloid A (AA) Amyloidosis in a Patient With Multiple Myeloma: A Case Report and Literature Review

Amyloidosis is a rare group of disorders characterized by the extracellular deposition of misfolded protein aggregates that interfere with the function of the tissue affected. In some patients, the presenting symptom of monoclonal gammopathies, such as multiple myeloma, can be a gastrointestinal bleed with a further report of amyloidosis in gastrointestinal samples. In all the cases the pathology report is read as AL (light chain) amyloidosis. We present a case of a 57-year-old male patient with no medical history who debuted with gastrointestinal bleeding. A colonoscopy revealed a colonic ulcer with a pathologic diagnosis of amyloid A (AA) amyloidosis. Further investigation led to the finding of multiple myeloma (MM) with no evidence of systemic amyloidosis. Although there is little evidence in the literature of the association or even causative relationship between multiple myeloma and AA amyloidosis, our case highlights the importance of searching for an underlying monoclonal gammopathy like MM in a patient with a confirmed diagnosis of AA amyloidosis.

AA amyloidosis complicating monoclonal gammopathies, an unusual feature validating the concept of "monoclonal gammopathy of inflammatory significance"?

INTRODUCTION

AL amyloidosis is caused by the proliferation of an immunoglobulin-secreting B cell clone. AA amyloidosis is a rare complication of chronic inflammation. However, some patients present with diseases combining monoclonal immunoglobulin production and chronic inflammation. The aim of this work was to describe cases of AA amyloidosis associated with monoclonal gammopathies.

PATIENTS AND METHODS

We reviewed all patients reported in French national amyloid centres presenting with AA amyloidosis and monoclonal gammopathy and performed a literature review. The quality of AA amyloidosis diagnosis and the causal relationship with monoclonal gammopathy were assessed.

RESULTS

In total, four patients from our centres and eight from the literature fulfilled the inclusion criteria. The haematological disorders presenting with monoclonal gammopathy were as follows: Waldenström macroglobulinaemia (n = 8), Schnitzler syndrome (n = 2), multiple myeloma (n = 1) and monoclonal gammopathy of undetermined significance (n = 1). Treatment strategies varied among the cases, with the treatment of the haematological disorder in 4 and anti-inflammatory treatment in 2.

CONCLUSION

Monoclonal gammopathies might be a rare and poorly known cause of AA amyloidosis. Such monoclonal gammopathies could be named "monoclonal gammopathies of inflammatory significance."

Causes of AA amyloidosis: a systematic review

From a clinical perspective, there is a need for a reliable and comprehensive list of diseases causing AA amyloidosis. This list could guide clinicians in the evaluation of patients with AA amyloidosis in whom an obvious cause is lacking. In this systematic review, a PubMed, Embase and Web of Science literature search were performed on causes of AA amyloidosis published in the last four decades. Initially, 4066 unique titles were identified, but only 795 full-text articles and letters were finally selected for analysis. Titles were excluded because of non-AA type of amyloidosis, language, no full-text publication or irrelevance. Hundred and fifty diseases were initially reported to be associated with the development of AA amyloidosis. The presence of AA amyloid was proven in 208 articles (26% of all) of which 140 (67%) showed a strong association with an underlying disease process. Disease associations were categorized and 48 were listed as strong, 19 as weak, 23 as unclear, and 60 as unlikely. Most newly described diseases are not really unexpected because they often cause longstanding inflammation. Based on the spectrum of identified causes, a pragmatic diagnostic approach is proposed for the AA amyloidosis patient in whom an obvious underlying disease is lacking.