Haematologica 2002; 87:(08)ELT39
[Medline] [prev] [index] [next]

Spurious thrombocytosis associated with cryoglobulinaemia: a case report
Mª Encarnación Pérez-Vila,^1,4 Carme Pedro,² Leonardo Mellibovsky³, Soledad Woessner,⁴ Sergi Serrano,¹ Lourdes Florensa^1,4
1Laboratori de Citologia Hematològica/Servei de Patologia; ²Servei d'Hematologia Clínica, ³Servei de Medicina Interna; and ⁴Escola de Citologia Hematològica S. Woessner-IMAS4, Hospital del Mar, IMAS, IMIM. Barcelona. Spain.
Correspondence: Mª Encarnación Pérez-Vila, Laboratori de Citologia Hematològica, Servei de Patologia, Hospital del Mar, Pg Marítim, 25-29, Barcelona 08003, Spain. Tel. 34/932483521. Fax. 34/932483131. E-mail: e0038@imas.imim.es

---

Spurious thrombocytosis (ST) associated with cryoglobulinaemia is an infrequent phenomenon triggered by cold.^1-5 It is caused by anomalous protein precipitates what are counted as platelets, when automated cell counters are used. We report a patient with an essential mixed type cryoglobulinaemia (EMTC) in whom spurious thrombocytosis of 1004x10⁹/L was detected.

A 45-years old male patient was remitted to our hospital to study of a chronic myeloproliferative syndrome; in a full blood count control in an automated cell counter (Advia 120, Bayer), was detected a thrombocytosis of 1004x10⁹/L. With antecedents of moderate enolic habit, occasional consumer of inhaled cocaine and parenteral heroin, hepatitis C virus, vitiligo and leucocytoclastic vasculitis, he had been diagnosed of EMTC a year before. Examination of the peripheral blood smear, did not confirm the thrombocytosis. The blood sample was incubated in a 37ºC bath and when newly was processed a valour of 107x10⁹/L platelet was obteined, which was confirmed by manual count in a Fuchs-Rosenthal camera. The pseudothrombocytosis coincided with an increase of his IgM k monoclonal gammopathy.
The automated cell counters can give spureous values in some pathologic states. False increases of the platelet number have been reported in presence of Howell-Jolly and Pappenheimer bodies, erythrocytes fragments, hairy cells cytoplasmic fragments in hairy cell leukaemia,^6,7 and, as in our case, by the existence of cryoglobulines. We emphasize, the importance of testing samples at 37ºC, when abnormal histograms were observed, as well as to perform a simultaneous observation of a peripheral blood smears and a manual count to highlight the discrepancy and to avoid unnecessary explorations (Figure 1).

References

1. Di Giovanni S, De Matteis MA, Ciocca D, et al. Pseudothrombocytosis and pseudoleukocytosis in a case of essential mixed cryoglobulinemia (type II). Clin Exp Rheumatol 1986; 2:143-5.
2. Patel KJ, Hughes CG, Parapia LA. Pseudoleucocytosis and pseudothrombocytosis due to cryoglobulinaemia. J Clin Pathol 1987; 40:120-1.
3. Pagliuca A, Hambley H, Mufti GJ. Coulter S Plus STKR histograms detect spurious elevation of leucocyte and platelet counts associated with cryoglobulinaemia. Blut 1989; 59:396-7.
4. Zandecki M, Dupriez B, Fenaux P, et al. Cytological and ultrastructural assesment of free crystals or precipitates associated with pseudoleucocytosis and pseudothrombocytosis in cryoglobulinemia. Nouv Rev Fr Hematol 1989; 31:397-402.
5. Ogawa M, Kabutomori O, Koh T, et al. Mixed type cryoglobulinemia discrepancy of platelet count measured with an automated cell counter and by manual count method. Rinsho Byori 1991; 39:1229-32.
6. Ballard HS, Sindhu G. Cytoplasmic fragments causing spurious platelet counts in hairy cell leukemia: ultrastructural characterization. Arch Intern Med 1981; 141:942-4.
7. Berkessy S. Cytoplasm fragmentation of malignant lymphoma cells. Folia Haematol Int Mag Klin Morphol Blutforsch 1983; 110:651-5.