Development of VX-II Carcinoma Model in Rabbit Uterus: Evaluation with MR Imaging and Histopathology

Kang, Byung Chul; Kim, Yoon Kyung; Lee, Min Sun; Lee, Geun Young; Hahn, Soo Yeon

Abstract

PURPOSE: To develop a VX-II carcinoma model in the rabbit uterus and to describe the MR imaging findings of an experimentally induced VX-II uterine carcinoma along with the histopathologic findings.
MATERIALS AND METHODS
13 New Zealand rabbits were included in this study. Two pieces of tissue suspension (1 mm3x2) of VX-II carcinoma were loaded in an 18 gauge disposable needle and the tissue embedded in the wall of each horn of the rabbits' uterus. We obtained the MR images at 2 weeks in group A (n=5), or at 2 and 4 weeks in group B (n=8). T2-weighted images were obtained using an extremity coil. On MR imaging, we measured the signal intensity of the tumor and the uterine wall. We also measured the size and shape of the tumor and we compared this with the histopathologic results.
RESULTS
On MR images obtained 2 weeks after inoculation, all the rabbit uteruses (group A and B, n=13) show a thick tubular wall, and the uteruses demonstrated a high signal intensity on T2-weighted images. The thickened uterine walls were measured as 3-10 mm (mean: 6.5 mm). Peritoneal nodules were observed in 3/13 rabbits (23%), the nodules measured 1.5-1.8x3.0 cm; uterine masses were observed in 3/13 rabbits (23%), and they measured 0.6-1.5x1.3-1.5 cm. On MR images obtained 4 weeks after the inoculations (group B, n=8), rabbit uteruses that had VX-II carcinoma show thick tubular wall in all cases (n=8, 100%) and round uterine masses (n=6, 75%). The thickened uterine walls measured 5-14 mm (mean 7.6 mm) and uterine masses measured 1.3-3.0x1.5-6.0 cm. All the rabbit uteruses having VX-II carcinoma showed high signal-to-noise ratios along the thickened uterine walls or masses on T2WI. On the histopathologic exam after sacrificing the rabbit, a few viable tumor cells were found because of necrosis in the inner portion of the uterine tumors, and abundant viable tumor cells were found at the periphery of the uterine tumors.
CONCLUSION
We can develop an animal model with uterine tumor in rabbit uterus using VX-II carcinoma. Experimentally induced VX-II carcinomas in rabbit uterus demonstrated central necrosis, and MR imagings of experimentally induced uterine VX-II carcinomas were well correlated with the histopathology.