title: Essential thrombocythemia or chronic idiopathic myelofibrosis? A single-center study based on hematopoietic bone marrow histology.
abstract: We reviewed a large series of patients with essential thrombocythemia diagnosed on the basis of the Polycythemia Vera Study Group criteria, and reclassified them by evaluating their major morphologic features and clinical course using the World Health Organization classification. The morphologic review of the bone marrow biopsies of 116 patients (44 males and 72 females; aged 19 - 83 years, median 55 years; median follow-up 121 months) led to 22 cases (19%) being classified as essential thrombocythemia (ET), 24 (21%) as chronic idiopathic myelofibrosis (CIMF)-0, 44 (37%) as CIMF-1, 13 (12%) as CIMF-2, 9 (8%) as latent phase polycythemia vera, and four (3%) as chronic myeloproliferative disorder, unclassifiable. There was a significant difference in the median age of the ET and fibrotic CIMF patients (54.7 +/- 13.55 vs. 59.13 +/- 15.05 years; P = 0.03). Histologic analysis showed that the simultaneous presence of loose clusters of large/giant megakaryocytes and nuclear hyperlobulation was significantly different between the ET and the prefibrotic CIMF (P<0.01) and fibrotic CIMF patients (P<0.01), and that the association of dense clusters of megakaryocytes with maturation defects and bulbous nuclei also distinguished the prefibrotic CIMF (P<0.05) and fibrotic CIMF patients (P<0.001) from those with ET. The association of cellularity, granulocytic proliferation and reticulin fibers was helpful in distinguishing prefibrotic from fibrotic CIMF (P<0.001).
authors.affiliation: II Cattedra di Anatomia Patologica, Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, A.O. San Paolo, Via Di Rudini 8, 20142 Milan, Italy, umberto.gianelli@alice.it
authors.forename: Umberto
authors.initials: U
authors.lastname: Gianelli
authors.forename: Claudia
authors.initials: C
authors.lastname: Vener
authors.forename: Paola Rafaniello
authors.initials: PR
authors.lastname: Raviele
authors.forename: Alessia
authors.initials: A
authors.lastname: Moro
authors.forename: Federica
authors.initials: F
authors.lastname: Savi
authors.forename: Claudio
authors.initials: C
authors.lastname: Annaloro
authors.forename: Francesco
authors.initials: F
authors.lastname: Somalvico
authors.forename: Franca
authors.initials: F
authors.lastname: Radaelli
authors.forename: Vito
authors.initials: V
authors.lastname: Franco
authors.forename: Giorgio Lambertenghi
authors.initials: GL
authors.lastname: Deliliers
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000473:pathology*; D001856:Bone Marrow Examination; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005260:Female; D006098:Granulocytes / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011087:Polycythemia Vera / Q000175:diagnosis* / Q000209:etiology; D055728:Primary Myelofibrosis / Q000175:diagnosis* / Q000209:etiology; D013920:Thrombocythemia, Essential / Q000175:diagnosis* / Q000209:etiology