Thrombotic Thrombocytopenic Purpura Triggered by Inflammatory Pseudotumor: A Report of a Rare Case
Authors: de Andrade Orsi Fernanda Loureiro , Benevides Thais , Moura Muriel S , Maria Maria A , Percout Priscila O. , Mazetto Bruna m , Ozelo Margareth C , Colella Marina Pereira , de Paula Erich V , Annichino-Bizzachi Joyce 
Published: October 2019

Abstract
Abstract 4660

Introduction:
Thrombotic thrombocytopenic purpura (TTP) is a rare disease characterized by microangiopathic anemia, thrombocytopenia and neurological or kidney damage. TTP occurs due to the deficiency of ADAMTS13, mainly because of autoantibodies against the enzyme. Treatment requires combination of plasmapheresis and steroids. Underline diseases must be ruled out and treated when present. Although well established in the literature, diagnosis and clinical management can be difficult because of the rarity of the disease.

Case report:
J.C.S., male, 41 years old, previously healthy. In March 2012 he developed malaise, abdominal pain, jaundice, fever, headache and hematuria, being initially treated as having leptospirosis. During the clinical course, he presented renal failure requiring dialysis, transient ischemic attack and thrombocytopenia. Tests showed microangiopathic hemolytic anemia, thrombocytopenia (< 10.000/uL) and increase of lactate dehydrogenase (3 times). The ADAMTS 13 plasma activity was 8% and autoantibody against ADAMTS 13 was positive, confirming the diagnosis of TTP. Plasmapheresis and steroid therapy (prednisone 1mg/kg) were started. Patient achieved clinical remission after seven daily sessions of plasmapheresis and the therapy was discontinued. At this time, the ADAMTS13 activity was 4.4% and the antibody was positive. After extensive etiological investigation, there was no evidence of any associated disease; serological tests, autoimmunity tests and tumor screening were negative. The bone marrow biopsy and CT scan of the thorax were normal and total abdominal ultrasound revealed slight splenomegaly. Ten days after the withdrawn of plasmapheresis therapy, patient had a clinical exacerbation and therapy was intensified with vincristine and a new cycle of plasmapheresis. However, patient did not achieve sustained clinical response to treatment and ADAMTS 13 was 7.8%. A CT scan of the abdomen showed a 15 cm retroperitoneal tumor, whose center was highly vascularized and the periphery was calcified, which was surgically resected. The pathological analysis concluded that it was a primary inflammatory pseudotumor, the hypotheses of Castleman's disease, lymphoma or other neoplasia were all ruled out. After tumor resection, patient had complete TTP remission and ADAMTS 13 normalization (105%), with sustained response during the follow-up (more than 40 days after surgery).

Conclusion:
In this report, we showed a case of TTP caused by a primary and localized inflammatory pseudotumor. This tumor probably triggered the formation of autoantibodies against ADAMTS 13, leading to the picture of TTP. The evidence that the patient had sustained clinical remission and normalization of ADAMTS 13 only after tumor removal supports this hypothesis. Many cases of TTP triggered by systemic infectious, autoimmune diseases or metastatic neoplasia have been reported before. However, of our knowledge, there are no published cases of TTP secondary to a localized and benign disease so far. This report highlights the importance of a comprehensive etiological investigation in cases of TTP, the role of plasmapheresis as adjuvant therapy and the need for specific treatment of the underlying disease.

Disclosures:
No relevant conflicts of interest to declare.