1. eMedicine - Hepatoblastoma : Article by Mary Elizabeth McCarville
Prior to contrast administration, an epithelial-type tumor appears as a homogeneous hypodense mass, while a mixed mesenchymal-epithelial tumor demonstrates a more heterogeneous appearance. On gross inspection, the epithelial type tends to be...
http://www.emedicine.com/radio/topic331.htm

2. Desmoplastic Small Round Blue Cell Tumor
The neoplasm was interpreted as a mixed mesenchymal and primitive neuroectodermal tumor (PNET) with histologic features reminiscent of a recently described intraabdominal desmoplastic small cell tumor.
http://www.thedoctorsdoctor.com/diseases/desmoplastic_srbct.htm

3. Uterine Sarcoma
Other rare forms of uterine sarcomas also fall under the WHO classification of mesenchymal and mixed tumors of the uterus. Sarcomas arising in the endometrial stroma, with a peak incidence occurring before menopause for the low-grade tumors and...
http://www.meb.uni-bonn.de/cancer.gov/CDR0000062938.html