Aa Amyloidosis in a Patient with Essential Thrombocythemia and Sclerosing Angiomatoid Nodular Transformation of the Spleen

Abstract

A 42-year-old Caucasian woman presented in 2007 with asymptomatic progressive thrombocytosis. Four years later, she developed a low-grade fever. Her hemoglobin remained normal, but the platelet count continued to increase, and the C-reactive protein (CRP) was significantly elevated (Tab. I).Two years later, she presented with melena and anemia due to hemorrhagic erosive gastroduodenitis. She received omeprazole and oral iron supplementation. The anemia was partially corrected, but severe thrombocytosis persisted. Ultrasound and computed tomography (CT) showed splenomegaly (87.5 mm 2 ) with a splenic mass that measured 68 mm × 65 mm × 68 mm. A bone marrow biopsy demonstrated increased megakaryocytes with atypical features. She was diagnosed with essential thrombocythemia and started on interferon-α. Her fever resolved, and the platelet count decreased to the normal range; she had mild proteinuria, persistent anemia, and elevated CRP (Tab. I).ABSTRACT Introduction: Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a rare condition with unknown pathogenesis, which is sometimes associated with hematological disorders. We present the case of renal and splenic AA amyloidosis associated with SANT and essential thrombocythemia -a previously unreported combination of pathologies. Case description: A 42-year-old Caucasian woman presented with a 6-year history of progressive thrombocytosis, low-grade fever, and elevated C-reactive protein (CRP). An abdominal ultrasound discovered a splenic mass, and a bone marrow biopsy revealed megakaryocytosis with atypical features. Under interferon-α treatment, her fever resolved and her platelet count decreased, but the CRP remained elevated. Within 2.5 years she developed nephrotic syndrome and kidney failure. A kidney biopsy revealed amyloidosis. She was started on hemodialysis and underwent a splenectomy. Splenic pathology revealed SANT and AA amyloidosis of the spleen. Further review of her biopsy specimens confirmed renal AA amyloidosis and myeloproliferative disorder. Polymerase chain reaction studies showed a JAK2 V617F mutation in 1% of nucleated cells. Anti-Epstein-Barr virus (EBV) immunoglobulin G (IgG)-Epstein-Barr nuclear antigen (EBNA) and IgG-viral capsid antigen were >600 U/mL. At the latest follow-up visit 1 year after the splenectomy, she is doing well; her platelet count and CRP are normal. Conclusions: Our patient has SANT and essential thrombocythemia associated with AA amyloidosis. The high titers of anti-EBV IgG suggest that chronic EBV infection may have been causative for the former 2 conditions. The return of her high CRP level to the normal range after surgical removal of the pseudotumor may suggest an association of AA amyloidosis with SANT.

Renal Amyloidosis

“…Moreover, we recently described a patient with sclerosing angiomatoid nodular transformation of the spleen and AA amyloidosis [8], association previously unreported ( Figures 5 and 6).…”