The Effect of Botulinum Toxin-A on the Survival of Random-Pattern Cutaneous Flap in Rat

PURPOSE: Botulinum toxin type A(BoTA) can block the release of vasoconstriction cotransmitters as well as acetylcholine in nerve terminal. The authors observed that BoTA increases flap survival by preventing sympathetic collapse of peripheral vessels. METHODS: 10 Sprague Dawley rats were divided into control(n=5), and BoTA group(n=5). 3x10cm sized random pattern cutaneous flaps were elevated on the dorsal side in both groups. In BoTA group, BoTA was injected into the flap via intradermal to subdermal route, 7 days before the flap elevation. Flap survival rates (survival area/total area) were measured 7 days after the elevation. Cutaneous blood flow was measured in proximal, middle and distal compartments of the flap using laser Doppler flowmetry initially, preoperatively, at immediate postoperation, and 7 days after flap elevation, respectively. Histological examination was performed 7 days after the flap elevation. The number and shape of the vessels were evaluated under microscope. RESULTS: Mean flap survival was 53.18+/-6.58% in control group and 93.79+/-6.06% in BoTA group, displaying statistically significant difference(p=0.0008, p< 0.05). In the control group, blood flow to the middle and distal compartments of the flap decreased significantly immediately after flap elevation. In the BoTA group, blood flow to the middle compartment did not decrease(p=0.002) and slightly decreased in the distal compartment(p=0.001). Cutaneous blood flow was significantly higher in all compartments of the flap in BoTA group than in control group, 7 days after the flap elevation. In histopathologic examination, greater number of vessels were noted in the BoTA group than in the control group. CONCLUSION: Botulinum toxin A can increase the survival of the random pattern cutaneous flap in rats by preventing the sympathetic collapse of peripheral vessels.

Microcystic Adnexal Carcinoma of the Lower lip: A Case Report

PURPOSE: Microcystic adnexal carcinoma is a rare malignant appendage tumor, first described by Goldstein et al in 1982. Here, we present our experience in treatment of a case on the lower lip. METHODS: A 52-year-old female with an asymptomatic nodule on the chin, previously misdiagnosed as trichoadenoma by needle aspiration biopsy, was treated by wide excision combined with multiple circumferential frozen biopsies. RESULTS: Pathological examination revealed typical features of microcystic adnexal carcinoma, such as basaloid and squamous cells forming nests and cord-like patterns, horn cysts, and minimal cytologic atypia. The patient has been followed up for 6 months. No sign of recurrence is noted to date. CONCLUSION: Differentiation from other benign adnexal neoplasms is important for its appropriate treatment. Differentiation can be difficult histologically because it is difficult to acquire an adequate biopsy due to its invasiveness, and clinically due to its asymptomatic and slow growing features. Complete excision is the key treatment, but it may not always be the best solution considering the huge defect that may result and the low incidence of metastasis & deaths owing to the tumor. We add this case to the approximately 300 cases reported worldwide with a review of literature.