Leuco-Thrombocytopenia Due to Splenomegaly in a Patient Affected by Retroperitoneal Fibrosis

Abstract

Idiopathic retroperitoneal fibrosis (RPF) is a rare clinical entity characterized by the progressive proliferation of connective tissue in the retroperitoneum. The chronic inflammatory process can entrap the retroperitoneal structures, mainly the ureters and the great vessels. Although the causes are unknown, immunogenetic factors and immunopathologic/autoimmune mechanisms are probably involved. The pathogenesis appears to be related to IgG4 autoimmune mechanisms (“hyper-IgG4 disease”). Surgical treatments are frequently performed such as ureterolysis and aneurysm repair; steroids and immunosuppressive agents are also used. In January 2008 a 62-year-old Caucasian man was referred to our institution for mild leucopenia and progressive thrombocytopenia. In 1999 he had a diagnosis of RPF treated surigically and complicated by chronic renal failure. He did not undergo regular follow-ups during the following years. When he came to our attention his peripheral blood count showed: Hb 14.5 g/dl, WBC 3.800/uL (N 60%, L 28%, M 8%), Plt 79.000/uL, confirmed by numerous measurements. He did not present signs or symptoms of cutaneous or mucosal bleeding and he did not report any recurrence of infectious episodes. At physical examination the spleen was palpable at 5 cm from the ribs, neither liver enlargement nor superficial lymphoadenopathies were noted. A peripheral blood (PB) smear showed only anisocytosis of red blood cells. To exclude an underlying hematologic disorder a bone marrow (BM) aspiration and a BM trephine biopsy were performed, both demonstrating a regular representation of the three hematopoietic series without any pathologic patterns. Cytogenetic examination revealed normal karyotype and molecular biology analyses resulted negative for Bcr/Abl rearrangement and for mutation V617F of JAK2 gene. Routine laboratory tests including liver function, LDH, Beta2 microglobulin serum levels, autoimmune tests, PB mononuclear cell immunophenotyping, viral sierology resulted within normal range. Abdominal ultrasound showed about 95 cm2 homogeneous splenomegaly and revealed an hyperechogenic rounded mass measuring 5–6 cm that completely embraced the splenic hilum. Splenic vein at the source was not visible and splenic flow was not measurable because of the hilum compression. Splenic vein in the retropancreatic site was measurable only partially: it presented thin caliber with normal directed blood flow inside. The abdominal CT exam confirmed the presence of a 5.6×7 cm solid tissue mass embracing the pancreatic tail and the splenic vessels and it extended across the spleno-pancreatic ligament. Moreover, the mass also involved the upper part of the left adrenal gland expanding until peri-renal space. Radiologically the mass was considered as RPF. In this case the retroperitoneal fibrotic tissue compresses the splenic hilum reducing the blood flow through the spleen thus causing congestive splenomegaly. The increase size of the spleen is responsible for thrombocytopenia as well as for leucopenia. The mechanism underlying splenomegaly-related thrombocytopenia is an induction of a reversible pooling of up to 90 percent of total body platelets. Both platelet production and the survival of platelets within the spleen are normal. Pooling is the major factor responsible for thrombocytopenia in uncomplicated splenomegaly. In this patient no hematologic specific treatment is indicated since neither thrombocytopenia nor leucopenia have clinical relevance. The aim of the therapy should be to reduce the progression of the fibrotic tissue to prevent further organ-related damages.