Primary Immune Thrombocytopenia (ITP) Guidelines for Bone Marrow Aspirate Reduce the Diagnostic Rate of Myelodysplastic Syndromes

Primary immune thrombocytopenia (ITP) is an acquired immune-mediated disorder characterized by isolated thrombocytopenia, defined as a peripheral blood PLT count <100 Gi/L, and the absence of any obvious initiating and/or underlying cause of the thrombocytopenia (Rodeghiero et al, Blood, 2009). Guidelines consider bone marrow (BM) aspirate informative in patients with thrombocytopenia > 60 years of age, those with systemic symptoms or abnormal signs or in some cases where splenectomy is considered (Provan et al, Blood, 2009).

We performed a retrospective chart analysis between January 2008 and June 2010 of all patients referred to our clinic for isolated thrombocytopenia but with a PLT count 100– 149 Gi/L. According to recent guidelines, these patients are not to be considered thrombocytopenic and do not require further investigation. The aim of the study was to evaluate the validity of omitting BM analysis in these cases.

Twenty-three cases (13 males/10 females) of mean age 58 ± SD 19 years were evaluated at our clinic for a PLT count below normal lab range values. At the time of evaluation none had bleeding symptoms. PLT counts ranged from 101 to 149 Gi/L, mean 123 Gi/L. Four patients had an enlarged spleen. After initial screening, 2 patients had a complex autoimmune disorder and 1 case had HCV hepatitis. The remaining 20 patients had a bone marrow (BM) aspirate performed: a diagnosis of myelodysplastic syndrome (MDS, WHO classification refractory thrombocytopenia) was obtained in 13 cases (65%) and BM biopsy was performed in 12, completed by cytogenetics in 9 cases (7 normal, 1 del20q, 1 –Y). Patients diagnosed with MDS were significantly older (66 ± SD 13 vs 47 ± SD 21 years, p = 0.017), but 4 cases (31%) were < 60 years of age (44, 49, 51 and 55 years of age, respectively).

The most recent guidelines, which lower the PLT threshold to 100 Gi/L from 150 Gi/L for the investigation of causes of thrombocytopenia, reduce the diagnostic rate of MDS. In our retrospective review, 65% of patients would not have had an early diagnosis of MDS. Furthermore, BM aspirate should be considered irrespective of age, since one third of the patients in our case review had MDS with PLT > 100 Gi/L as a single cytopenia and age under 60.

No relevant conflicts of interest to declare.