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Highly malignant non-Hodgkin lymphomas (HM-NHL) may sometimes develop clinical features simulating an epithelial carcinoma with metastatic dissemination. Conventional histopathological study may be insufficient to differentiate between both conditions. Two patients with HM-NHL are reported with a rapid general deterioration; one of them had osteolysis and hypercalcemia. In both cases a diffuse bone marrow infiltration by large sized cells with blastic appearance was found. The initial suspected diagnosis was occult epithelial neoplasia with metastatic dissemination. The morphological study with optic microscopy and the ultrastructural analysis did not establish the origin of these cells. The definitive diagnosis was obtained by immunohistochemical techniques. In both cases, the cells were positive for the CD 45 (common leukocyte antigen) monoclonal antibody (MoAb), and for several MoAbs of lymphoid B differentiation. In one of them, the B lymphoid lineage was confirmed by monoclonal reordering of the gene that synthetises the immunoglobulin heavy chain.

A patient is presented in whom the diagnoses of chronic myelomonocytic leukaemia (CMML) and erythroblastopenia were simultaneously established. Besides the conventional criteria for both haemopathies, the culture of bone-marrow precursor cells showed lack of growth of the erythroid stem cells. 6-Mercaptopurine given as therapy for CMML failed to induce any favourable changes in erythroblastopenia, which in turn improved with prednisone. Nevertheless, the patients died five months after diagnosis due to acute transformation of the CMML.

Studies dealing with the number or size of individual adipose cells in human bone marrow are lacking. To ascertain whether the age-related variations in fat tissue fraction depend on the size of individual adipocytes or their number or both, a stereological study of 20 normal human bone marrow specimens was performed. A total number of 17,039 adipose cell profiles was measured and two stereological parameters were obtained in each specimen: mean diameter and number of cells per mm3 of bone marrow. With increasing age, an increasing fat tissue fraction was observed (r = 0.61; p = 0.004). The fat tissue fraction correlated positively with the size (r = 0.81; p less than 0.001) and the number/volume (r = 0.59; p = 0.006) of adipocytes. The significance of both adipocyte size and adipocyte number/volume was confirmed by stepwise multiple regression, in which the size alone explained 66.2% of fat tissue fraction and both size and number/volume explained 97.2% of fat tissue fraction. These results are discussed from a pathophysiological point of view.

It has been established that cytogenetic findings at the time of diagnosis of acute myeloid leukemia (AML) are powerful prognostic indicators. Pericentric inversion of chromosome 16 and translocation t(16;16) resulting in chimeric fusion of CBFB and MYH11 genes are typically seen in the M4-Eo FAB classification subset of AML and are associated with low-risk disease. These subtle chromosomal abnormalities may be difficult to detect in poor-quality metaphase preparations and if missed could lead to incorrect assignment to risk groups and influence the therapy decision-making process.We prospectively studied, at diagnosis, 10 patients with AML-M4 Eo by cytogenetics and fluorescent in situ hybridization (FISH) with two cosmids (36 and 40). As a control group, 7 patients (5 with a diagnosis of AML other than M4 Eo and two cases of reactive eosinophilia) were analyzed. In addition reverse transcriptase chain reaction (RT-PCR) studies were carried out in 6 cases.Karyotypic analysis detected the inv(16) in all but one of the patients with M4-Eo while none of the control cases showed any abnormality on chromosome 16. FISH studies showed that all 10 patients had abnormalities on chromosome 16; the patient with normal karyotype showed an inv(16) by FISH, while a case with inv(16) by cytogenetics had a t(16;16) by FISH. RT-PCR demonstrated amplification of the CBFB/MYH11 product in all cases analyzed.In patients with M4Eo and rearrangements of chromosome 16, FISH studies may afford more complete information than conventional cytogenetics and can be an alternative to RT-PCR studies.

To assess whether the variations in the number and size of the adipocytes are proportional, or not, to the changes of the fat tissue fraction (FF) associated to different degrees of hematopoietic cellularity of the bone-marrow.The material was made up of 28 specimens of bone marrow biopsy, from which 265 microscopic fields representing a wide range of FF were obtained. As index of proportionality, the ratio N/S (adipocyte number/size) was employed.The parameters FF and N/S showed a highly significant correlation (r = 0.89; p = 0.00000003) at low-normal FF range (40%), whereas at high FF range (40%), such a correlation was lacking (r = 0.01; p = 0.86).At low-normal FF the adipocyte number and size vary proportionally. Conversely, at high FF, in some cases a more marked increase of number and in other instances of adipocyte size is detected. Further investigations are needed to find out the responsible factors for this different behaviour.

Abnormalities of the long arm of chromosome 3 (3q) involving bands 3q21 and/or 3q26 occur in 2-6% of myeloid malignancies. Trilineage myelodysplasia, especially in the megakaryocytic line, is a characteristic feature. Additional abnormalities of chromosomes 5 and 7 are usually present. The response to treatment and prognosis are poor.The main clinical, cytologic (bone marrow aspirate and biopsy) and cytogenetic characteristics as well as the response to the treatment in 10 patients with 3q abnormalities diagnosed in a single hospital in a period of 8 years are referred.Eight patients had acute non-lymphoblastic leukemia, being de novo in five of them. The median value of hemoglobin was 87 g/l (range: 51-148), white blood cells count 5.8 x 10(9)/l (1.2-47.1) and platelet count 34 x 10(9)/l (5-182). The morphological findings in the study of the bone marrow were: dyserythropoietic features (7 patients), dysgranulopoietic abnormalities (5 patients) and small-sized megakaryocytes with hypolobulated nuclei (8 patients). Fibrosis was observed in the 4 cases in which a bone marrow biopsy was performed. In addition to the 3q alteration, abnormalities of chromosomes 7 (4 patients), 5q (2 patients) and +8 (2 patients) were present. Four patients received intensive chemotherapy and in two of them a complete remission was achieved, but relapse occurred at 3 and 5 months, respectively. All patients have died, the median survival being 7 months.3q abnormalities define a subtype of myeloid malignancies with characteristic clinical and morphological features. The response to therapy and survival are poor.