Suppression and azimuthal anisotropy of prompt and nonprompt J/psi production in PbPb collisions at root S-NN=2.76 TeV

The nuclear modification factor RAA and the azimuthal anisotropy coefficient v2 of prompt and nonprompt (i.e. those from decays of b hadrons) J/ψ mesons, measured from PbPb and pp collisions at sNN−−−√=2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pT>6.5 GeV/c and rapidity |y|<2.4 , extending down to pT=3 GeV/c in the 1.6<|y|<2.4 range. The v2 of prompt J/ψ is found to be nonzero, but with no strong dependence on centrality, rapidity, or pT over the full kinematic range studied. The measured v2 of nonprompt J/ψ is consistent with zero. The RAA of prompt J/ψ exhibits a suppression that increases from peripheral to central collisions but does not vary strongly as a function of either y or pT in the fiducial range. The nonprompt J/ψ RAA shows a suppression which becomes stronger as rapidity or pT increases. The v2 and RAA of open and hidden charm, and of open charm and beauty, are compared

Challenging diagnostic issues in adenomatous polyps with epithelial misplacement in bowel cancer screening: five years' experience of the BCSP Expert Board

The diagnostic difficulties of differentiating epithelial misplacement from invasive cancer in colorectal adenomatous polyps have been recognised for many years. Nevertheless, the introduction of population screening in the UK has provided extraordinary diagnostic problems. Larger sigmoid colonic adenomatous polyps, those most likely to show epithelial misplacement, are specifically selected into such screening programmes because these polyps are likely to bleed and screening is based on the detection of occult blood. The diagnostic challenges associated with this particular phenomenon have necessitated the institution of an "Expert Board": this is a review of the first five years of its practice, during which time 256 polyps from 249 patients have been assessed. Indeed, the constitution of the Board has been with three pathologists because those pathologists do not necessary agree and a consensus diagnosis is required to drive appropriate patient management. However, this study has shown substantial levels of agreement between the three Expert Board pathologists whereby the ultimate diagnosis has been changed, from that of the original referral diagnosis, by the Board in half of all the polyps, in the substantial majority from malignant to benign. In 3% of polyp cases, the Expert Board consensus has been the dual diagnosis of both epithelial misplacement and adenocarcinoma, further illustrating the diagnostic difficulties. The Expert Board of the Bowel Cancer Screening Programme in the UK represents a unique and successful development for an extraordinary diagnostic conundrum created by the particular characteristics of bowel cancer screening

Desmoplastic Trichilemmoma of the Facial Region Mimicking Invasive Carcinoma

Trichilemmoma is a hamartomatous proliferation arising from cells of hair follicle. Its desmoplastic variant simulates an invasive carcinoma. In this tumor, the cell of origin seems to be located in the superficial level of the hair follicle just below the basement membrane at the sebaceous gland level. We present a similar case which presented with an asymptomatic nodular lesion in the region above the upper lip on left side. Fine needle aspiration cytology raised the cytological possibility of a malignancy for which the lesion was excised. On histopathology the lesion was diagnosed as desmoplastic trichilemmoma. The case highlights the difficulty encountered in differentiating a benign adnexal tumor from malignant lesion based on cytology alone. Moreover, the extensive desmoplasia on histopathology raises the suspicion of invasive malignancy which requires to be carefully excluded. The superficial features of trichilemmoma and lack of cellular atypia is a useful diagnostic clue in such a situation. Positivity of CD34 can also be used to differentiate from basal cell carcinomas. The case reported here had a solitary lesion, but follow up is required for development of more lesions or multiple hamartomas in other organs as a part of Cowden’s disease