We performed a multicentric study to assess the impact of two different culture procedures on the detection of chromosomal abnormalities in 217 consecutive unselected cases with chronic lymphocytic leukemia (CLL) referred for routine analysis either at the time of diagnosis (n = 172) or during disease evolution (n = 45). Parallel cultures of peripheral blood or bone marrow were set up with the addition of either the conventional B-cell mitogen 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or a combination of CpG oligonucleotide (CpG) and interleukin-2 (IL-2). Cytogenetic analyses were performed on both cultures. Clonal abnormalities were identified in 116 cases (53%). In 78 cases (36%), the aberrant clone was detected in both cultures. Among these, the percentages of aberrant metaphases were similar in both conditions in 17 cases, higher in the CpG/IL-2 culture in 43 cases, and higher in the TPA culture in 18 cases. Clonal aberrations were detected in only one culture, either in CpG/IL-2 or TPA in 33 (15%) and 5 (2%) cases, respectively. Taken together, abnormal karyotypes were observed in 51% with CpG/IL-2 and 38% with TPA (P < 0.0001). Application of FISH (n = 201) allowed the detection of abnormalities not visible by conventional cytogenetic analysis in 80 cases: del(13q) (n = 71), del(11q) (n = 5), +12 (n = 2), del(14q) (n = 1), and del(17p) (n = 1). In conclusion, our results confirm that CpG/IL-2 stimulation increases the detection rate of chromosomal abnormalities in CLL compared with TPA and that further improvement can be obtained by FISH. However, neither conventional cytogenetics nor FISH detected all aberrations, demonstrating the complementary nature of these techniques.

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Plasmacytoid dendritic cells (PDC) belong to a subtype of dendritic cells that are normally absent in healthy skin. In some inflammatory diseases of the skin, especially lupus erythematosus (LE), these cells are occasionally recruited in great amounts, which can be used as a helpful clue for diagnosis. Rarely, PDC may also accumulate in the skin of patients with myeloid leukemia, a yet poorly known condition currently called 'tumor-forming PDC associated with myeloid neoplasms'. In this study, we describe a patient with unsuspected chronic myelomonocytic leukemia who developed cutaneous lesions characterized by a dermal infiltrate rich in PDC. Similarly to LE, such neoplastic PDC were accompanied by interface dermatitis-like changes, but displayed an aberrant phenotype and shared the same chromosomal abnormality with the leukemic cells identified in the bone marrow, thus revealing the neoplastic nature of the process. This observation illustrates that tumor-forming PDC associated with myeloid neoplasms may microscopically mimic LE in some patients. Accordingly, a hematologic workup is recommended in any skin lesion featuring excessive numbers of PDC, even if morphological alterations suggestive of interface dermatitis are found.

Key Clinical MessageMaternal uniparental disomy of chromosome 14 (upd(14)mat) is responsible for a Prader–Willi‐like syndrome with precocious puberty. Although upd(14) is often hypothesized to result from trisomy rescue mechanism, T14 cell lines are usually not found with postnatal cytogenetic investigations. We report the coexistence of both chromosomal abnormalities in a 15‐year‐old girl.

We report a new case of giant cell ependymoma (GCE) of the thoracic spinal cord. Ependymomas predominate in children and young adults and are frequently intracranial and infra-tentorial. However, a second age peak at 30-40 years is reported for spinal tumours. Microscopically, ependymomas show a large variety of histological features, among which a rare variant with giant cells. This 59-year-old woman presented with a 6-month history of numbness and burning sensation affecting the left lower limb and hemi-trunk. A cervico-thoracic MRI revealed a solid intra-medullary tumour at the level of T1-T3, slightly T1-hypointense, T2-hyperintense and contrast enhancing. A complete surgical resection was carried out through a C7 to T4 laminectomy. Recovery was complete with no sign of recurrence at 18-month follow-up. The initial histological diagnosis of glioblastoma was challenged on the basis of the imaging and operative findings of a well-circumscribed tumour. The case was sent to us for second opinion and we diagnosed a GCE, WHO grade II, with a biphasic pattern including a predominant giant cell component (>90%), with genetic evidence of polyploidy, and a very limited classic component, showing a characteristic loss of chromosome 22. Our report adds to the clinical, imaging, pathological and genetic characterisation of GCE and brings the first genetic evidence that these rare tumours are at least bi-clonal. It also suggests that GCE have a good prognosis after complete surgical resection.