Prevalence and clinicopathological characteristics of lipomatous neurofibromas in neurofibromatosis 1: An investigation of 229 cutaneous neurofibromas and a systematic review of the literature.

BACKGROUND: Lipomatous neurofibroma (Lnf) is a histopathological variant with adipocytes noted among cells of cutaneous neurofibromas. We aimed to investigate the prevalence and clinicopathological features of Lnfs of neurofibromatosis 1 (NF1)-associated cutaneous neurofibromas and to review the literature systematically. We also evaluated the expression of leptin (a hormone involved in lipid metabolism) in neurofibromas to better understand the pathogenesis of Lnfs. METHODS: A prospective histologic study was conducted on 229 cutaneous neurofibromas from 85 NF1 individuals. Leptin expression was immunohistochemically evaluated in 111 cutaneous neurofibromas. To systematically review the literature, two authors independently performed literature searches without year restriction. RESULTS: Forty (17.5%) neurofibromas were lipomatous. Lnfs were significantly larger lesions and associated with females. Eighteen (7.9%) of all neurofibromas had multinucleated floret-like giant cells, and these were associated with Lnfs. All neurofibromas expressed leptin. We systematically reviewed 13 articles. Three large studies investigated Lnfs mainly in sporadic neurofibromas and suggested that 0.3% to 8.0% of tumors (NF1 and sporadic) are Lnfs. CONCLUSION: In NF1, Lnfs are common, mainly in larger tumors and women. All cutaneous NF1-neurofibromas express leptin. It is unknown if the expression of leptin accounts for the lipomatous variant, but it may have a role in the pathogenesis of cutaneous neurofibroma.

Effect of tamoxifen on fibrosis, collagen content and transforming growth factor-ß1, -ß2 and -ß3 expression in common bile duct anastomosis of pigs.

End-to-end anastomosis in the treatment for bile duct injury during laparoscopic cholecystectomy has been associated with stricture formation. The aim of this study was to experimentally investigate the effect of oral tamoxifen (tmx) treatment on fibrosis, collagen content and transforming growth factor-ß1, -ß2 and -ß3 expression in common bile duct anastomosis of pigs. Twenty-six pigs were divided into three groups [sham (n = 8), control (n = 9) and tmx (n = 9)]. The common bile ducts were transected and anastomosed in the control and tmx groups. Tmx (40 mg/day) was administered orally to the tmx group, and the animals were euthanized after 60 days. Fibrosis was analysed by Masson's trichrome staining. Picrosirius red was used to quantify the total collagen content and collagen type I/III ratio. mRNA expression of transforming growth factor (TGF)-ß1, -ß2 and -ß3 was quantified using real-time polymerase chain reaction (qRT-PCR). The control and study groups exhibited higher fibrosis than the sham group, and the study group showed lower fibrosis than the control group (P = 0.011). The control and tmx groups had higher total collagen content than the sham group (P = 0.003). The collagen type I/III ratio was higher in the control group than in the sham and tmx groups (P = 0.015). There were no significant differences in the mRNA expression of TGF-ß1, -ß2 and -ß3 among the groups (P > 0.05). Tmx decreased fibrosis and prevented the change in collagen type I/III ratio caused by the procedure.

Tamoxifen decreases the myofibroblast count in the healing bile duct tissue of pigs.

OBJECTIVE: The aim of this study was to evaluate the effect of oral tamoxifen treatment on the number of myofibroblasts present during the healing process after experimental bile duct injury. METHODS: The sample consisted of 16 pigs that were divided into two groups (the control and study groups). Incisions and suturing of the bile ducts were performed in the two groups. Tamoxifen (20 mg/day) was administered only to the study group. The animals were sacrificed after 30 days. Quantification of myofibroblasts in the biliary ducts was made through immunohistochemistry analysis using anti-alpha smooth muscle actin of the smooth muscle antibody. Immunohistochemical quantification was performed using a digital image system. RESULTS: In the animals treated with tamoxifen (20 mg/day), there was a significant reduction in immunostaining for alpha smooth muscle actin compared with the control group (0.1155 vs. 0.2021, p = 0.046). CONCLUSION: Tamoxifen reduced the expression of alpha smooth muscle actin in the healing tissue after bile duct injury, suggesting a decrease in myofibroblasts in the scarred area of the pig biliary tract. These data suggest that tamoxifen could be used in the prevention of biliary tract stenosis after bile duct surgeries.

Tamoxifen decreases the myofibroblast count in the healing bile duct tissue of pigs

OBJECTIVE: The aim of this study was to evaluate the effect of oral tamoxifen treatment on the number of myofibroblasts present during the healing process after experimental bile duct injury. METHODS: The sample consisted of 16 pigs that were divided into two groups (the control and study groups). Incisions and suturing of the bile ducts were performed in the two groups. Tamoxifen (20 mg/day) was administered only to the study group. The animals were sacrificed after 30 days. Quantification of myofibroblasts in the biliary ducts was made through immunohistochemistry analysis using anti-alpha smooth muscle actin of the smooth muscle antibody. Immunohistochemical quantification was performed using a digital image system. RESULTS: In the animals treated with tamoxifen (20 mg/day), there was a significant reduction in immunostaining for alpha smooth muscle actin compared with the control group (0.1155 vs. 0.2021, p = 0.046). CONCLUSION: Tamoxifen reduced the expression of alpha smooth muscle actin in the healing tissue after bile duct injury, suggesting a decrease in myofibroblasts in the scarred area of the pig biliary tract. These data suggest that tamoxifen could be used in the prevention of biliary tract stenosis after bile duct surgeries.