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thrombotic thrombocytopenic purpura

Wednesday 21 April 2004

Thrombotic thrombocytopenic purpura (TTP) is a rare haematological disease of unknown aetiology. This thrombotic microangiopathy is characterized by microvascular lesions with platelet aggregation.

Thrombotic thrombocytopenic purpura (TTP) is found in adults and can be associated with pregnancy, cancer, autoimmune diseases, bone marrow transplantation, drugs and bacterial as well as viral infections. Even if TTP is immediately treated in an adequate manner, it still shows a mortality of up to 20%.

Etiology - Associations

- pregnancy-associated thrombotic thrombocytopenic purpura
- cancer-associated thrombotic thrombocytopenic purpura

  • occult adenocarcinoma

- autoimmune diseases
- bone marrow allograft (7806094, 2297591)

- drugs-associated thrombotic thrombocytopenic purpura

  • cyclosporin-associated thrombotic thrombocytopenic purpura
  • statin (15356359)

- bacterial infections

- viral infections

Synopsis

- renal lesions
- pulmonary lesions
- splenic lesions

  • splenomegaly
  • splenic arterial thrombi
  • splenic arteriolar thrombi
  • periodic acid-Schiff-positive diastase-resistant hyaline subendothelial deposits (SEDs)
  • transition between thrombi and SEDs in splenic arterioles
  • platelets or platelet-related material in SEDs and thrombi
  • hyperplasia of white pulp (B-cells and germinal centers)
  • splenic periarteriolar concentric fibrosis (onion-skin appearance)
    - splenic hemosiderosis (siderophages and prominent iron deposits)
  • splenic hemophagocytosis
  • splenic extramedullary hematopoiesis
  • splenic blood lakes
  • splenic infarcts
  • splenic endothelial hyperplasia
  • no splenic microaneurysms

References

- Aster RH. Thrombotic thrombocytopenic purpura (TTP)—an enigmatic disease finally resolved? Trends Mol Med. 2002 Jan;8(1):1-3. PMID: 11796254

- Allford SL, Machin SJ. Current understanding of the pathophysiology of thrombotic thrombocytopenic purpura. J Clin Pathol. 2000 Jul;53(7):497-501. PMID: 10961171

- Saracco SM, Farhi DC. Splenic pathology in thrombotic thrombocytopenic purpura. Am J Surg Pathol. 1990 Mar;14(3):223-9. PMID: 2106272