Cytogenetic abnormalities in pediatric myelodysplastic syndrome: a report of three cases

Three consecutive cases of pediatric myelodysplastic syndrome (MDS) diagnosed over a three-year period in Queen Mary Hospital, Hong Kong, were described. Depending on the classification system used, they comprised two cases of chronic myelomonocytic leukemia (CMMoL) of which one can be reclassified as juvenile chronic myeloid leukemia (JCML) and one cases of refractory anemia with excess of blasts (RAEB) or an alternative diagnosis of atypical CML. Cytogenetic abnormalities were detected in all of them on examination of bone marrow cells. Of the two CMMoL, one had monosomy 21, whereas the other had hypodiploidy. The patient with RAEB had a complex karyotype of 46,X,del(X)(q24),t(1;7) (p22;q32),add(15)(q26)(8). The balanced translocation (1;7) seen in this patient was exceedingly rare and, to the best of our knowledge, was reported only twice in the literature. The karyotypic abnormalities that we saw in our patients were not well recognized in pediatric MDS. This report emphasizes the importance of cytogenetic study in children suspected of suffering from MDS, which remains a rare disorder of childhood, and a need to rationalize current classification schemes.

Aggressive pleomorphic CD2+, CD3-, CD56+ lymphoma with t(5;9)(q31;q34) abnormality

CD56-positive lymphoma is a recently described entity which is characterized by predominantly extranodal involvement and an aggressive clinical course. We report one such case with involvement of the bone marrow and spinal cord at presentation, and associated with reactive hemophagocytic syndrome. The lymphoma cells had a highly pleomorphic appearance which is uncommon in CD56-positive lymphoma. Cytogenetic studies revealed a t(5;9)(q31;q34) abnormality. Analysis of more cases is required to determine if this is a recurring chromosomal translocation characteristic of the group of aggressive CD56-positive lymphoma.

Hepatosplenic gamma delta T-cell lymphoma. A distinctive aggressive lymphoma type

The T-cell receptor (TCR) expressed on the surface of most T-lymphocytes is of alpha beta type, and only a minority bear the gamma delta-TCR. Similarly, postthymic T-cell lymphomas rarely express gamma delta-TCR. Hepatosplenic gamma delta T-cell lymphoma is an uncommon entity that has so far not been widely recognized. We report one such case that has been comprehensively studied by multiple modalities and showed the unique occurrence of leukemic picture at presentation. The 39-year-old man presented with fever, marked weight loss, and massive splenomegaly. Peripheral blood showed thrombocytopenia and a white cell count of 5.8 x 10(9)/l, with 66% medium-sized lymphoid cells that had a round or folded nucleus, condensed chromatin and a moderate amount of pale blue cytoplasm. Splenectomy was performed and histologic examination of the spleen, bone marrow, liver, and abdominal lymph nodes demonstrated lymphoma infiltration with a predominantly sinusoidal pattern. Immunohistochemical studies of the lymphoma cells showed a T-cell phenotype: CD2+ CD3+ CD5+ CD7+ gamma delta-TCR+ alpha beta-TCR- CD56+ CD4- CD8- CD16- CD57-. Cytogenetic studies showed complex clonal chromosomal abnormalities of 44,X, -Y, -11, -22, + mar in 3/16 cells. Rearrangement of the TCR gamma chain gene was demonstrated by polymerase chain reaction; the TCR beta chain gene was partially chain reaction; the TCR beta chain gene was partially rearranged. The patient did not respond to single agent chemotherapy, but achieved clinical remission with combination chemotherapy. Based on the available data in the literature, hepatosplenic gamma delta T-cell lymphoma exhibits distinctive clinicopathologic features, and probably represents the neoplastic counterpart of splenic gamma delta T-lymphocytes. This disease is associated with a poor prognosis and usually relapses despite initial response to chemotherapy.

Refractory cytopenia with t(1;7),+8 abnormality and dysplastic eosinophils showing intranuclear Charcot-Leyden crystals: a fluorescence in situ hybridization study

A case of refractory cytopenia and marrow eosinophilia showing t(1;7) translocation and concomitant trisomy 8 is reported. The eosinophils were dysplastic, and showed the unique feature of intranuclear Charcot-Leyden crystal formation, giving rise to a 'lip-like' appearance. We speculate that this unusual cytologic feature resulted from abnormal precipitation of Charcot-Leyden crystal protein in the eosinophils. By fluorescence in situ hybridization using a chromosome 8 specific alpha-satellite probe, the abnormal eosinophils were shown to have derived from the abnormal clone. We postulate that the dysplastic clone might have retained a differentiation potential and be responsive to normal haemopoietic stimuli.

B-cell small lymphocytic lymphoma with circulating granular prolymphocytes and a novel trisomy 15 anomaly

A 53-year-old man presented with cervical lymphadenopathy and massive splenomegaly. Peripheral blood examination showed many prolymphocytes with cytoplasmic azurophilic granules, giving an initial impression of large granular lymphocytosis. The lymph node biopsy and immunohistochemical study findings, however, were more compatible with a diagnosis of B-cell small lymphocytic lymphoma. The circulating prolymphocytes showed restricted kappa light chain expression similar to the lymphoid infiltrate in the lymph node. Karyotypic analysis revealed trisomy 15, a chromosomal abnormality that has rarely been described in small lymphocytic lymphoma or chronic lymphocytic leukemia.

Megakaryoblastic transformation of polycythemia vera associated with hypercalcemia

Leukemic transformation is not uncommon in polycythemia vera, particularly after treatment with chemotherapeutic agents. The leukemias that supervene are mostly of myeloid type but megakaryoblastic transformation is distinctly uncommon. We report a case of polycythemia vera terminating in megakaryoblastic leukemia with associated hypercalcemia.

Acquired immunodeficiency syndrome presenting as marrow cryptococcosis

Disseminated cryptococcal infection is an uncommon initial manifestation in patients with the acquired immunodeficiency syndrome. The most common sites of involvement by cryptococci are the central nervous system and the lungs, and involvement of the marrow is rare. There are few descriptions in the literature on the cytologic findings of marrow cryptococcosis. We report a patient with disseminated cryptococcosis in which cytologic examination of the marrow provides the first clue to the diagnosis.

Solid tumour with initial presentation in the bone marrow--a clinicopathologic study of 25 adult cases

This study reviews the clinicopathologic features of 25 adult patients without a known history of malignancy presenting with metastatic carcinoma in the bone marrow. The disease mainly affected middle-aged to elderly males (mean age, 61.6 years). Bone pain, generalized or confined to the back, was a common presenting complaint. Organomegaly was often absent. Laboratory abnormalities included anaemia, leukocytosis, thrombocytopenia and a leukoerythroblastic blood picture. Serum alkaline phosphatase level was raised in the majority of cases. In about one-third of the cases, malignancy was not suspected clinically, and bone marrow aspiration was carried out because of incidental finding of abnormal blood counts. The marrow aspirate findings were characterized by numerous to sparse cohesive tumour clusters with nuclear moulding. Over two-thirds of the patients had metastatic adenocarcinoma, and the lung was found to be the commonest site of primary disease. We conclude that since the marrow infiltration can be subtle, marrow smears should be carefully scrutinized for tumour cells in patients with leukoerythroblastic blood picture, in particular those with an elevated serum alkaline phosphatase level.

Concurrent acute myeloid leukemia and systemic mastocytosis

A 51-year-old woman presented with concurrent systemic mastocytosis and acute myeloid leukemia associated with a clonal karyotypic anomaly of t(8;21). Cytochemical, histologic, and cytogenetic studies helped in the distinction from a recently described entity: acute myeloid leukemia with marrow basophilia. Although the leukemia responded well to aggressive chemotherapy, the mastocytosis component worsened, illustrating the inherent resistance of mastocytosis to chemotherapy.

Turbidimetric ultracentrifugation. Application to the study of human serum very low density lipoprotein distributions

In this communication it is shown that the sedimentation coefficient distribution may be accurately measured for very large particles using turbidimetric techniques and the ultraviolet-scanning analytical ultracentrifuge. A principal advantage is that turbidity is a function of the product of concentration and molecular weight; thus, large particles may be observed even when present in very small amounts. We propose to call this method of analysis "turbidimetric ultracentrifugation." We have used turbidimetric ultracentrifugation ot determine the sedimentation coefficient distribution for a sample of human serum very low density lipoproteins. This distribution is compared to that found with conventional schlieren techniques with good agreement.

Binding of [3H]atropine by cardiac plasma membrane-enriched fractions

The binding of [3H]atropine by the primary subcellular fractions and plasma membrane-enriched fractions from atria and ventricles of various species was measured by the Millipore filtration technique. Although all of the primary particulate fractions exhibited binding activities, the bulk of the total homogenate binding activity was associated with the washed particles sedimenting at the lower gravitational forces; this was observed with either atria or ventricles of dog, guinea pig, rabbit, hamster, and rat. Plasma membrane-enriched fractions isolated from the right atrium of guinea pig exhibited atropine binding activities with characteristics similar to dog atrial membranes; binding activity was moderately enriched in these membranes with respect to the starting material.