Primary cutaneous large B-cell lymphoma shows activation of nuclear factor kappa B and low incidence of Epstein-Barr virus.

Primary cutaneous lymphomas are defined as lymphomas, which are present in the skin without evidence of extracutaneous disease at the time of diagnosis. Primary cutaneous large B-cell lymphoma (PCLBCL) is a subtype of primary cutaneous B-cell lymphoma with a female predominance, occurring in elderly patients and known to have unfavorable prognosis. We evaluated 10 cases of PCLBCL in immunocompetent patients between 2005 and 2008. A panel of immunoperoxidase stains; CD3, CD10, CD20, BCL2, BCL6, and MUM1 were performed on all cases. Nuclear factor kappa B (NF-kappaB) pathway activation was evaluated using an immunostain for P65. The presence of Epstein-Barr virus (EBV) was assessed using Epstein-Barr virus encoded RNA (EBER) in situ hybridization probe. All cases were CD20 positive and CD3 negative. CD10, BCL6, BCL2, and MUM1 were positive in 4/10 (40%), 6/10 (60%), 7/10 (70%), and 7/10 (70%) cases, respectively. NF-kappaB activation was detected in 7/10 (70%) cases. One (10%) case was positive for EBV by in situ hybridization. Interestingly, the EBV positive case was also positive for MUM1 and negative for CD10, indicating an activated immunophenotype. In conclusion, majority of PCLBCL shows activation of NF-kappaB pathway with a low incidence of EBV.

Real time analysis of the affinity regulation of alpha 4-integrin. The physiologically activated receptor is intermediate in affinity between resting and Mn(2+) or antibody activation.

This work examines the affinity of alpha(4)beta(1)-integrin and whether affinity regulation by G protein-coupled receptor (GPCR) and chemokines receptors is compatible with cell adhesion mediated between alpha(4)-integrin and vascular cell adhesion molecule-1. We used flow cytometry to examine the binding of a fluorescent derivative of an LDV peptide (Chen, L. L., Whitty, A., Lobb, R. R., Adams, S. P., and Pepinsky, R. B. (1999) J. Biol. Chem. 274, 13167-13175) to several cell lines and leukocytes with alpha(4)-integrin ranging from about 2,000 to 100,000 sites/cell. The results support the idea that alpha(4)-integrins exhibit multiple affinities and that affinity changes are regulated by the dissociation rate and conformation. The affinity varies by 3 orders of magnitude with the affinity induced by binding mAb TS2/16 plus Mn(2+) > Mn(2+) ' TS2/16 > activation because of occupancy of GPCR or chemokines receptor > resting receptors. A significant fraction of the receptors respond to the activating process. The change in alpha(4)-integrin affinity and the corresponding change in off rates mediated by GPCR receptor activation are rapid and transient, and their duration depends on GPCR desensitization. The affinity changes mediated by IgE receptor or interleukin-5 receptor persist longer. It appears that the physiologically active state of the alpha(4)-integrin, determined by inside-out signaling, has similar affinity in several cell types.

Phakomatous choristoma: a case report and review of the literature.

Phakomatous choristoma is a rare congenital lesion of the eyelid that can be clinically and/or histologically mistaken for a cyst, cutaneous adnexal neoplasm, or an ocular adnexal oncocytoma. Only 13 such cases have been previously described, mostly in the English language ophthalmic literature. Zimmerman reported the first case in 1971 and proposed the lesion to be of lenticular anlage origin, a theory that has been widely accepted. We report an additional case occurring in an 8-week-old male infant with a firm nodule of the right lower eyelid that was present since birth. A 15 x 12 x 2 mm circumscribed solid nodule with a homogenously white cut surface was surgically excised. Histologically, this lesion was comprised of cuboidal cells forming cystically dilated and irregularly branched ducts and cords within a densely fibrotic stroma. Also present were eosinophilic basement membranelike material, psammoma body-like calcifications and intraluminal degenerated ghost cells. The immunohistochemical profile of the epithelial cells included strong immunoreactivity for vimentin, focal weak staining for S-100, and negative staining for cytokeratin, epithelial membrane antigen, synaptophysin, and chromogranin. The irregularity of the ducts and cords of epithelial cells within the densely fibrotic stroma resembled an infiltrative neoplasm of cutaneous adnexal or lacrimal duct origin. However, the site of involvement, the peculiar basement membrane material, ghost cells, and immunohistochemical profile were features that helped to distinguish phakomatous choristoma from an infiltrative carcinoma. The correct identification of this lesion is essential to avoid an aggressive surgical excision, thus sparing the eyelid and lacrimal system. The purpose of this article is to bring attention to this rare entity, because it has not been described in either the dermatology or dermatopathology literature and furthermore, is not mentioned in any of the major dermatopathology texts.