Intraoperative touch imprint cytological analysis of sentinel lymph nodes for the presence of metastases in malignant melanoma.

AIM: Sentinel lymph node (SLN) biopsy has revolutionized lymph node staging in patients with malignant melanoma. Intraoperative evaluation is a new addition to the SLN procedure that allows for a one-step regional lymph node dissection to be performed when the SLN biopsy findings are positive. The discriminatory immunostaining pattern with the S-100 and HMB45 monoclonal antibodies allows intraoperative immunocytochemical evaluation of imprint smears of SLNs for melanoma metastases. METHODS: One hundred twenty eight SLNs from a cohort of 52 patient-cases that had been identified using sulfur colloid as a radioactive tracer and isosulfan blue were bisected for rapid Diff-Quick stained touch preparations. Intraopera-tive evaluation of sentinel node status by imprint cytology was correlated with the histopathological results of permanent sections. Tumor-negative nodes in routine paraffin sections were further investigated with the employment of the S-100 and HMB45 antibodies. RESULTS: Thirty-six of all SLNs harbored metastases in paraffin sections, from which 32 were identified by imprint cytology (sensitivity 88.8%). Three SLNs were positive by imprint cytology and negative by histopathology of paraffin sections. Comparison of the results of the touch preparations with the final histopathology (hematoxylin-eosin and S-100/ HMB45 stains) demonstrated a sensitivity of 83.3% and a negative predictive value of 92.5%. The specificity and positive predictive value were 100% respectively. CONCLUSION: Touch imprint cytology is potentially useful for intraoperative evaluation of SLNs in malignant melanoma patients. Results can be improved if the surface sampled is appropriately enlarged and a rapid immunohistochemical S-100/HMB45 stain on the imprints is utilized.

Normal development of fetal hepatic haematopoiesis during the second trimester of gestation is upregulated by fibronectin expression in the stromal cells of the portal triads.

OBJECTIVE: in midtrimester fetuses the principal site of hematopoiesis is the liver. In hematopoietic organs, stromal cells such as fibroblasts, epithelial cells, and macrophage-like cells develop networks to maintain hematopoiesis, i.e. hematopoietic stem cell self-renewal, proliferation, and growth, by interaction with hematopoietic progenitor cells. ECM glycoproteins produced by the stromal cells are known to play a critical role in the regulation of cell growth and differentiation. Numerous soluble and membrane-bound factors directly regulating haematopoiesis have been documented, but little is known about fetal hepatic stromal cell activity and stromal extracellular matrix protein-fibronectin, on fetal hepatic haematopoiesis. The binding of late stage erythroid cells to fibronectin has been well characterized and is believed to be critical for the terminal stages of erythroid differentiation. The intention of this article is to determine the role of fibronectin in fetal hepatic hematopoietic proliferation and differentiation in different stages of development. MATERIAL AND METHOD: we examined and compared the immunohistochemical expression of fibronectin in the hepatic stromal portal fields in the 1st, 2nd, and 3rd trimester of gestation respectively, in relation to the appearance of CD34 progenitor hematopoietic, stromal progenitor and vascular endothelial positive cells. RESULTS: our results demonstrated a quantitative difference in the second trimester of gestation concerning the expression of fibronectin in the connective tissue stroma of the hepatic portal fields over the equivalent expression of the protein in the first (p < 0.0001, t-test) and third trimester (p < 0.0001, t-test). Similar changes in the above period were found concerning the expression of CD34 during the second trimester of gestation, over the first (p < 0.0001, t-test) and third trimesters (p < 0.0001, t-test), suggesting a direct involvement of fibronectin in the sustaining of hematopoietic activity. CONCLUSIONS: our data provide evidence that an ECM glycoprotein component, fibronectin, plays a relevant role in hematopoiesis through interaction between stromal cells and hematopoietic progenitor cells.

Normal development of fetal hepatic haematopoiesis during the second trimester of gestation is upregulated by fibronectin expression in the stromal cells of the portal triads

Objetivo: en el segundo trimestre de la gestación, el principalfoco de hematopoyesis del feto es el hígado. En los órganoshematopoyéticos, las células del estroma, como fibroblastos,células epiteliales y células de tipo macrófago, desarrollan redespara mantener la hematopoyesis, es decir, la auto-renovación,la proliferación y el crecimiento de las células madre hematopoyéticas,al interactuar con las células progenitoras hematopoyéticas.Se sabe que las glucoproteínas de la MEC producidaspor las células del estroma desempeñan un papel crítico enla regulación del crecimiento y la diferenciación celulares. Sehan documentado numerosos factores solubles y de membranaque regulan directamente la hematopoyesis, pero se sabe pocode la actividad de las células del estroma hepático y de laproteína (fibronectina) de la matriz extracelular en el feto en relacióncon la hematopoyesis hepática. La unión de las célulaseritroides tardías a la fibronectina está bien tipificada y se creeque es crítica para las etapas terminales de la diferenciación eritroide.La intención de este artículo es determinar el papel dela fibronectina en la proliferación y diferenciación hematopoyéticadel hígado fetal en las distintas etapas del desarrollo.Material y método: examinamos y comparamos la expresióninmunohistoquímica de fibronectina en los campos portalesdel estroma hepático durante los trimestres primero, segundoy tercero del embarazo en relación con la aparición decélulas progenitoras hematopoyéticas CD34, progenitoras delestroma y endoteliales vasculares, respectivamente.Resultados: nuestros resultados mostraron una diferenciacuantitativa en cuanto a expresión de fibronectina en el estromadel tejido conjuntivo de los campos portales en el segundotrimestre de embarazo respecto al primero (p < 0,0001, pruebade la t) y respecto al tercero (p < 0,0001, prueba de la t). Sehallaron también cambios similares en cuanto a la expresión deCD34 respecto al primer (p < 0,0001, prueba de la t) y el tercertrimestres (p < 0,0001, prueba de la t), lo que indica la participacióndirecta de la fibronectina en el mantenimiento de laactividad hematopoyética

Objective: in midtrimester fetuses the principal site ofhematopoiesis is the liver. In hematopoietic organs, stromal cellssuch as fibroblasts, epithelial cells, and macrophage-like cells developnetworks to maintain hematopoiesis, i.e. hematopoietic stemcell self-renewal, proliferation, and growth, by interaction withhematopoietic progenitor cells. ECM glycoproteins produced by thestromal cells are known to play a critical role in the regulation of cellgrowth and differentiation. Numerous soluble and membraneboundfactors directly regulating haematopoiesis have been documented,but little is known about fetal hepatic stromal cell activityand stromal extracellular matrix protein-fibronectin, on fetal hepatichaematopoiesis. The binding of late stage erythroid cells to fibronectinhas been well characterized and is believed to be criticalfor the terminal stages of erythroid differentiation. The intention ofthis article is to determine the role of fibronectin in fetal hepatichematopoietic proliferation and differentiation in different stages ofdevelopment.Material and method: we examined and compared the immunohistochemicalexpression of fibronectin in the hepatic stromalportal fields in the 1st, 2nd, and 3rd trimester of gestation respectively,in relation to the appearance of CD34 progenitor hematopoietic,stromal progenitor and vascular endothelial positive cells.Results: our results demonstrated a quantitative difference inthe second trimester of gestation concerning the expression of fibronectinin the connective tissue stroma of the hepatic portalfields over the equivalent expression of the protein in the first (p <0.0001, t-test) and third trimester (p < 0.0001, t-test). Similarchanges in the above period were found concerning the expressionof CD34 during the second trimester of gestation, over thefirst (p < 0.0001, t-test) and third trimesters (p < 0.0001, t-test),suggesting a direct involvement of fibronectin in the sustaining ofhematopoietic activity