Postsplenectomy Thrombocythemia: An Unmasked Myeloproliferative Disorder

Abstract

Persistent postsplenectomy thrombocythemia should be differentiated from transient postsplenectomy thrombocytosis, as the former leads to hemorrhagic and thrombotic complications. The authors reviewed 29 cases of "postsplenectomy thrombocythemia" collected from the literature and added 2 of their own. The data on these 31 cases indicate that the disease should be diagnosed and treated as primary thrombocythemia, present in masked form before splenectomy.

The incidence of thrombotic and hemorrhagic disorders in association with extreme thrombocytosis: An analysis of 129 cases

“…Moreover, we found that serious thrombohemorrhagic complications in patients with extreme thrombocytosis were uncommon, even in those with MPD. This agrees with the findings of Kessler et a1 [9] but is contrary to many previous reports [l, 2,6,13]. Of the 129 patients studied, 97 (75 %) had no thrombohemorrhagic symptoms at the time of diagnosis and 83 (64%) were asymptomatic throughout their disease course.…”

Essential Thrombocythaemia

“…The cytogenetic studies performed showed normal karyotypes, as has been reported by others (26,32,35,36,42,70,71). The reported cytogenetic abnormalities in ET have shown a preponderance of C and G group abnormali ties (17,19,29,60) similar to those found in other myeloproliferative syn dromes (16,36,60,72).…”

“…Bone marrow examina tion showed panmyelosis with a striking increase in megakaryocytes which were large and tended to have many lobes, as has been described by others (32,43,55). The NAP scores, serum lysozyme and vitamin Bi2 levels were variably abnormal in our patients, in keeping with the findings of others (13,19,26,29,32,34,43,57).…”

“…The 3 patients described displayed the characteristic clinical and haematological features of ET (25,29,32,43,51,62), and at no time displayed features suggestive of polycythaemia vera, myeloid leukaemia or myelofibrosis. All pa tients had splenomegaly and suffered from both haemorrhage and thrombosis.…”

“…Ultrastructural studies of the platelets showed proliferation of the dense tubular system with deficiency of the surface-connected canalicular system. Megakaryocyte electron microscopy showed abnormal distribution of demarcation membrane complex and granules.The precise functional abnormality of the platelets in ET has not yet been defined, but a release defect of variable severity with corresponding morphological abnormalities of the dense tubular and surface-connected canalicular systems, seems the most likely explanation.Essential thrombocythaemia (ET) is now a well-recognised entity within the spectrum of the myeloproliferative disorders, and the clinical picture and general laboratory features are reasonably well defined (19,25,29,32,43,51,62). However, investigations of the bleeding tendency using qualitative platelet func tion tests and studies of platelet and megakaryocyte morphology and ultrastruc ture have not shown consistent abnormalities.…”