The treatment of hypertrophic scar (HS) has thus far been a clinical challenge. We evaluated the therapeutic effect of CO ₂ fractional laser combined with 5-fluorouracil ethosomal gel (5-FU EG) in rabbit HS model. HS model was established as standardized scars on the ventral surface of rabbit ears, divided into four groups: control (no intervention), EG treatment, laser treatment, and combined treatment group (laser plus 5-FU EG). Clinical macroscopic and H&E-stained microscopic observations were conducted to assess HS improvement. The mRNA levels of types I and III collagen, transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) were detected by real-time PCR. After 14 days, H&E staining shows that the thickness of HS in treatment groups was significantly lower compared with the control group, and the thickness in laser treatment group and combined treatment group was significantly lower compared with the EG treatment group. The mRNA levels of types I and III collagen, TGF-β1 were significantly low in all treatment groups, whereas IL-6 was highest in the laser treatment group at day 14. The macro- and microscopic effects of the combined and CO ₂ fractional laser treatment were better compared with 5-FU EG only. Inhibition of types I and III collagen, TGF-β1 are the possible underlying mechanism of action, whereas the function of IL-6 remains to be further studied. Our study suggests that the effect of combined 5-FU EG and laser, as well as laser-only treatment are superior to 5-FU EG monotreatment. The mechanism of HS improvement is related to reduction of collagen I/III and the inhibition of TGF-β1 expression.

Background: Dermatofibrosarcoma protuberans (DFSP) is a rare, low to intermediate-grade sarcoma, which needs imaging examination. Small series of ultrasound findings in DFSP have been published; however, the usefulness of elastography and contrast-enhanced ultrasound (CEUS) in DFSP has not been studied. We aim to study multimodal ultrasound findings and report the correlation between imagings and tiny extension in DFSP for preoperative evaluation. Methods: Two-D ultrasound, 3-D color ultrasound, elastography, and CEUS findings were retrospectively evaluated. Forty histopathologically confirmed DFSPs were studied. Results: On 2-D ultrasound, 26(65%) appeared as mostly hypoechoic lesions with occasional hyperechoic dots within the tumor matrix and lobulated lateral borders. Eight (20%) lesions were multilayered. Ninety-five percent of lesions showed increased vascularity. On 3-D ultrasound, DFSPs showed branch-shaped, striped, and wrapped color patterns. Power Doppler showed mainly artery of a moderate arterial peak systolic blood flow and low resistance index. DFSP is hard on elastography. On CEUS, DFSPs showed a long peak time, low peak and a small amount of perfusion around the tumor, 73.7% (14/19) of lesions showed a heterogeneous contrast enhancement and 89.5% (17/19) of lesions showed hyper-enhancement. CEUS showed better concordance than US with histology on the maximum diameter and depth (P < 0.05). Conclusions: Multimodal ultrasound showed significant characteristics in DFSP, which would improve diagnostic accuracy. CEUS could be an effective tool to determine tiny tumor extension.