T. Buhr

Chronic Myeloproliferative Disorders in Bone Marrow Biopsies

This Diagnostic Seminar intends to announce that CMPDs can be classified from BMB histologically by a rather simple system, which can be applied by interested histopathologists successfully. The rationale of this classification is to stay within the groups of diseases which are outlined by clinical findings including the peripheral blood and bone marrow smears. The concept of traditional classification as given by the WHO and textbooks, however, has to be revised as follows (1) Primary diseases of CMPDs must be distinguished from advanced disorders. Primary diseases are CML, P. vera, Thrombocythemia, CMGM, and unclassifiable CMPD. (2) Idiopathic, primary myelosclerosis of the bone marrow is a reactive feature consecutive to neoplastic transformation of hematopoiesis, i.e. myeloproliferation. (3) Advanced disorders comprise (3.1.) excess of blasts and blast crisis, and (3.2.) early myelosclerosis, myelosclerosis and myelofibrosis, advanced myelofibrosis. Advanced disorders are designated by a composed term classifying them among the groups of primary disease and specifying the advanced stage by a suffix, so that the underlying disease remains coining the term, even in unclassifiable cases in which only CMPDs can be applied. (4) The CML group must be subtyped into CML of common type versus that with increase or predominance of megakaryocytes. By this system of classification, it seems possible to classify and type the spectrum of variations occurring among CMPDs to a satisfying result.

Histologic findings in bone marrow biopsies of patients with thrombocythemic cell counts

SummaryHistologic diagnoses from bone marrow biopsies were analyzed in a total of 1165 patients presenting with thrombocythemic platelet counts at initial examination. Two cut-off points suggested by the Polycythemia Vera Study Group to define thrombocythemia by platelet counts were compared: the former limiting value of 1000×109/l platelets versus the recently proposed value of 600×109/l. The percentage of all nonproliferative disorders was 41% under the lower, dropping to 11% under the high cut-off point. The respective figures for myeloproliferative disorders increased from 49% under the lower to 74% under the high limiting value. Primary thrombocythemia was included in 72% by the lower, and in only 40% by the high limiting value when classified by its histologic pattern in bone marrow biopsy. A striking decrease of platelet counts occurs, related to fiber increase, among each of three main groups of myeloproliferative disorders: in CML with megakaryocytic predominance from 40% down to 25%, in megakaryocytic-granulocytic myelosis (primary, i.e., agnogenic myelofibrosis) from 36.6% to 10%, and in primary thrombocythemia from 72.6% to 28.6% in cases with reticulin sclerosis.

The impact of megakaryocyte proliferation for the evolution of myelofibrosis Histological follow-up study in 186 patients with chronic myeloid leukaemia

A histological study on sequential bone marrow biopsies in patients with chronic myeloid leukaemia (CML) was performed. We wished to answer the question as to whether a different content of megakaryopoiesis in the bone marrow of CML patients has a prognostic significance for the development of myelofibrosis during the course of disease. In addition, the significance of possible changes in the quantity of megakaryopoiesis in this process was assessed. In 186 patients who had no fibre increase at first diagnosis, the rate of subsequent myelofibrosis varied from 19% for the common or granulocytic subtype (CML.CT) to 40% for patients with features of megakaryocytic increase (CML.MI). No significant differences were found either in the rapidity of progression to fibrosis or in the final rate of osteomyelosclerosis. Whereas in CML.MI most patients (75%) showed an increase of fibres only, this was accompanied by an additional increase of megakaryocytes in CML.CT, changing the histological pattern from CML.CT to MI or MP, respectively. The data therefore revealed a correlation between fibre increase and subtyping of CML as suggested by the Hannover classification of chronic myeloproliferative diseases. Subtypes of CML with megakaryocytic increase could be shown to present a “pre-myelofibrotic” stage of disease and may therefore be conceived as a particular pathway of acceleration.

Immunohistochemical Examination of Routinely Processed Bone Marrow Biopsies

Immunohistochemistry was performed on paraffin sections of 169 bone marrow biopsies fixed in a buffered methanol-formalin solution and decalcified with EDTA. The biopsies included specimens with normal hematopoiesis, and specimens that were affected by various hematological disorders as well as some metastatic carcinomas. The results demonstrate that a wide spectrum of antigens was preserved in routinely processed bone marrow biopsies, even after long-term fixation up to 12 days. Markers for granulopoietic cells were lysozyme, elastase, DAKO-M 1, and MT 1. Megakaryopoiesis was stained with glycoprotein IIIa, von Willebrand factor, and Ulex europaeus agglutinin (UEA), and erythropoiesis with LN 1. Normal lymphocytes as well as lymphoma cells of all non-Hodgkins lymphomas tested were positive for leukocyte common antigen (LCA), and at variable degree, for MB 1, 4 KB 5, LN 1, LN 2, UCHL 1, or MT 1. Reed-Sternberg and Hodgkins cells in Hodgkins lymphomas were reactive with Ber-H 2, LN 2 and Dako-M 1. In plasma cell disorders, staining for immunoglobulin light chains gave best results. Metastatic carcinomas showed predominantly staining with EMA, and KL 1. A selected panel of specific cell markers is proposed, which proved to be helpful in routine bone marrow diagnosis in most cases.

Cytogenetics of chronic myelogenous leukemia (CML) correlated to the histopathology of bone marrow biopsies

SummaryCytogenetic findings were correlated to histopathological bone marrow findings evaluated simultaneously in 103 patients with chronic myelogenous leukemia (CML). CML was subtyped histologically according to the number of megakaryocytes and increase of fibers or blasts within the bone marrow. The Philadelphia chromosome (Ph1) was found in 88.3% of all patients (91/103). Chromosome aberrations additional to the Ph 1-chromosome were noticed in 20 of 91 (22%) cases. The additional karyotype changes occurred significantly more frequently among patients with increase of fibers in the bone marrow compared with patients without increase of fibers or blasts (p<0.05). Karyotype changes associated with increase of fibers in Ph 1-positive cases of CML were trisomy 8 and 19, +Phl, t (1; 11), and i (17q). Ph 1-positive CML patients with additional karyotype changes had a significantly shorter survival (p<0.04) than Ph 1-positive patients without additional chromosome aberrations. Our results suggest that histopathological examination of the bone marrow should be considered in the evaluation of cytogenetic markers in chronic myeloproliferative disorders.

Preleukemia: Bone Marrow Histopathology in Myelodysplasia and Preleukemic Syndrome

Precursors of leukemia have been widely discussed since the term “preleukemia” was introduced by Hamilton-Peterson (1949) and Block et al. (1953). Characteristic cytological features in blood and bone marrow have been defined as common precursors of acute nonlymphocytic leukemia (ANLL) by Saarni and Linman (1973), also termed hemopoietic dysplasia by Linman and Bagby (1978) and preleukemic syndrome (PLS) by Bagby (1985). The occurrence of blasts preceding the clinical symptoms of overt ANLL has long been recognized, with the introduction of various terms such as “smouldering” or “oligoblastic” leukemia, which are also used to designate preleukemic conditions (Rheingold et al. 1963; Seauer et al. 1974; Izrael 1975). The terminology has thus become confused, with many ambiguities and synonyms (Bagby 1985).

Evidence from molecular genetic and cytogenetic analyses that bone marrow histopathology is reliable in the diagnosis of chronic myeloproliferative disorders

SummaryThe reliability of histopathological diagnosis in bone marrow specimens from patients with chronic myeloproliferative disorders (CMPD) was evaluated by correlating the histological findings with molecular genetic and cytogenetic analyses of the Ph1-translocation. A rearrangement of m-bcr was detected only in patients (28/30) diagnosed histologically as chronic myeloid leukemia (CML). This finding was supported by the presence of a Ph1-chromosome in 24/26 patients with CML examined. All the patients with other types of CMPD, including polycythemia vera (PV), primary thrombocythemia (PTH) and chronic megakaryocytic-granulocytic myelosis (CMGM), as well as those with unclassifiable CMPD (CMPD.UC) were Ph1-negative (n = 38). The histopathological discrimination of CML from Ph1-negative varieties of CMPD was also reliable for patients with myelofibrosis complicating CML, CMGM and CMPD.UC. The results demonstrate that bone marrow histopathology allows a reliable diagnosis of CML. This is in contrast with hematological data such as high platelet counts which show considerable overlapping in the various forms of CMPD.

Das histologische Bild der Anämien in Knochenmarksbiopsien

ZusammenfassungDie Auswertung von 6 366 Untersuchungen, die wegen unklarer Anämie im Knochenmarksregister in den Jahren 1989 bis Juni 1994 untersucht worden sind, zeigt eine eindeutige Zunahme des Anteils der Anämien an den Einsendungen: 1989 waren es nur 7,2 %, im ersten Halbjahr 1994 aber 18,9 %, der Durchschnittswert beträgt rund 15 % in den insgesamt 41 553 in dieser Zeit untersuchten Biopsien. Die Zunahme ist v. a. auf die Zahl von Untersuchungen bei den über 50 jährigen zurückzuführen, die 73 % der 5 011 untersuchten Patienten ausmachen. Dies hängt besonders mit dem auf das Alter konzentrierten myelodysplastischen Syndrom zusammen, das mit fast 32 % Anteil die weitaus häufigste Ursache einer Anämie im Register ist. Neben dem myelodysplastischen Syndrom sind die Anämien infolge einer Entzündung oder infolge eines Mangels an Speichereisen im Knochenmarksregister mit 23,5 bzw. 22,7 % Anteil besonders häufig. Weitere, jedoch mit einem Anteil zwischen 3 und 7,2 % weit weniger bedeutende Ursachen einer Anämie sind in absteigender Häufigkeit die vielschichtige Gruppe der hämolytischen Anämien, die aplastische Anämie sowie die Gruppe der megaloblastären bzw. echten periziösen Anämie und die Anämie bei Blutung. Die einzelnen Anämieformen können durch typische histologische Veränderungen in der Biopsie des Knochenmarks unterschieden werden. Die Histopathologie der 6 wesentlichen Hauptgruppen wird beschrieben.SummaryA total of 41,553 bone marrow biopsies were collected for the Bone Marrow Registry from January 1989 to June 1994 included 6,366 taken from 5,011 patients referred because of unexplained anemia. An increasing percentage of biopsies submitted for examination are designated anemic: this rose from 7.2 % in 1989 to 18.9 % within the first 6 months of 1994, reflecting an increased need to find the reasons for anemic conditions. Histologically, seven main groups have been found: (1) myelodysplastic syndrome (MDS) accounting for 32 % of all anemia patients seen, (2) infectious anemia (23.5 %), (3) iron deficiency anemia (22.7 %), (4) hemolytic anemias (7.2 %), (5) aplastic anemia (6.8 %), (6) megaloblastic/pernicious anemia (5.0 %), and (7) anemia due to bleeding (3.0 %). These seven groups of anemia can be diagnosed in core biopsies on the basis of their particular histopathology, so that films of bone marrow smears are not always needed.

Histopathologie der Ph1-negativen Chronischen Myeloproliferativen Erkrankungen

ZusammenfassungDie großen Gruppen der chronischen myeloproliferativen Erkrankungen (CMPE) können histopathologisch ziemlich sicher unterschieden werden. Die Aussage stützt sich auf die Auswertung von 2 331 CMPE, die in den Erst-Biopsien von 34 160 Patienten zwischen 1989 und 1994 festgestellt worden sind. Die diagnostischen Biopsien dieser 2331 Patienten verteilen sich auf die 4 Hauptgruppen der CMPD wie folgt: CML 23,2 %; primäre Thrombozythämie 22,1 %; echte Polyzythämie 20,4 %; Chronische megakaryozytäre granulozytäre Myelose 22,3 %, und unklassifizierbare Fälle 12 %. Das Fortschreiten der chronischen Erkrankungen wird durch Zunahme und Pleomorphie der Megakaryozyten, zunehmende Myelofibrose und auch durch Auftreten von Blasten bestimmt. Diese 3 histologischen Leitveränderungen können in diagnostischen Biopsien vor jeder Behandlung beobachtet werden. Deshalb empfiehlt sich, diese Veränderungen semiquantitativ anzugeben. Dazu wird eine Einteilung in jeweils 4 Stadien von 0 bis 3 angegeben, womit jeder Patient durch seine diagnostische Biopsie, ähnlich der FAB-Klassifikation beim MDS, charakterisiert werden kann.SummaryThe Ph1-negative groups of chronic myeloproliferative diseases (CMPD) are described, and histopathological criteria that distinguish them from each other are given. These are based upon observations in primary biopsies from 2,331 patients with CMPDs among a total of 34,160 patients referred between 1 January 1989 and 30 June 1994 to the Bone Marrow Registry. These cases of CMPD break down into the main groups as follows: CML 23.2 %, megakaryocytic myelosis consistent with agnogenic myeloid metaplasia 22.3 %, essential thrombocythemia 22.1 %, and polycythemia vera 20.4 %; 12.0 % of cases were unclassifiable. Histological progress in each group is characterized by (1) increasing number and pleomorphy of megakaryocytes, (2) increasing fibrosis, and (3) excess of blasts. These three features can be observed in diagnostic biopsies before any therapy. Therefore, it is recommended that such alterations be reported semiquantitatively. A staging system with four stages from 0 to 3 for each of the three features is introduced. Its application allows staging for the individual patient on the basis of diagnostic biop-sies.

Histopathologie der chronischen myeloischen Leukämie in diagnostischen Biopsien vom Knochenmark

ZusammenfassungDie Histopathologie der chronischen myeloischen Leukämie (CML) wird aus den diagnostischen Biopsien des Knochenmarks von 412 Philadelphia-positiven Patienten beschrieben. Besonders berücksichtigt wird die Verteilung der Megakaryozyten, die Vermehrung von Fasern, von Blasten und von speichernden Histiozyten, nämlich der Pseudo-Gaucher-Zellen. Die Megakaryozyten waren eindeutig vermehrt bei 31,6 % der Patienten am Tag der Diagnose. Eine erkennbare Myelofibrose wiesen 15,8 % auf, eine deutliche Blastenvermehrung 2,4 % der Patienten. Speichernde Histiozyten vom Typ der Pseudo-Gaucher-Zellen zeigten 57,8 % im Knochenmark. Die Veränderungen werden als morphologische Kriterien der fortschreitenden Erkrankung interpretiert. Es bietet sich an, die CML semiquantitativ einzuteilen, was einfach und sicher durchgeführt werden kann. Damit wird die Erkrankung aus der Knochenmarkbiopsie heraus besser verständlich und für Verlaufsuntersuchungen definiert.SummaryHistopathology of the bone marrow of diagnostic biopsies prior to any therapy is described in a total of 412 Ph1-positive patients. Special attention is paid to the distribution of megakaryocytes, increase of fibres and blasts, and occurrence of storing histiocytes of pseudo-Gaucher type. Megakaryocytes were significantly increased in 31.6 % of diagnostic biopsies, myelofibrosis was found in 15.8 %, significant increase of blasts in 2.4 %. Pseudo-Gaucher cells were detected in 57.8 % of a total of 412 biopsies. These histiological features are considered as an indication of the progress of the disease. A semiquantitative specification of CML by this criteria is described which can be performed rather reliably and defines the stage of CML at diagnosis prior to substantial treatment.