Clinical and cytogenetic studies of two cases of Klinefelter syndrome with hereditary retinoblastoma and rhabdomyosarcoma.

Two children with Klinefelter syndrome (KS), one associated with bilateral hereditary retinoblastoma (RB) and the other with rhabdomyosarcoma (RMS) are reported. Both were boys and chromosomally mosaic for KS. The hereditary retinoblastoma case yielded 46,XY,del(13)(q12q14.2)/47, XXY(c),del(13)(q12q14.2) in PHA-stimulated lymphocytes. The rhabdomyosarcoma case yielded 46,XY/ 47,XXY(c) in peripheral blood cells whereas tumor revealed trisomy 8, trisomy 7, and t(7;13)(q33;q32) in addition to 46,XY/47,XXyc mosaicism.

Anaplastic large cell lymphoma of true histiocytic origin in an infant: unusual clinical, hematological, and cytogenetic features.

We report here the case of a 7-month-old boy who developed anaplastic large cell lymphoma of true histiocytic origin or malignant histiocytosis, with fever, bone and bone marrow infiltration. Usual clinical features were absent. The neoplastic nature of the disease was supported by the presence of clonal chromosomal abnormalities [t(6;8)(p23;p21),der(8)del(8)(q11aq13), der(22) t(11;22) (q13;13)]. Neither B nor T lineage could be demonstrated here. Morphology, ultrastructural analysis, surface antigens expression, and cytogenetics were more specific for the monocyte-macrophage lineage.

Chromosomal findings in cultured melanocytes from a giant congenital nevus.

A giant congenital pigmented nevus was observed in a newborn male. A melanocyte culture was established from nevus fragments removed at age 6 days. Analysis of 136 metaphases harvested from the primary culture showed 74% normal mitoses, 22% polyploids, and 4% mitoses with chromosome rearrangements involving in particular 1p, 12q, and 19p. In addition, the culture showed a high level of HLA-DR expression. Although histology showed no sign of malignancy, these findings may illustrate one of the first events which might eventually progress toward malignancy.