Final answer:
A complex solid tumor that is indistinguishable from other retroperitoneal neoplasms such as pancreatic cancer, brain tumors, breast cancer, and more.
Step-by-step explanation:
This complex solid tumor is indistinguishable from other retroperitoneal neoplasms such as pancreatic cancer, brain tumors, breast cancer, cervical cancer, metastatic prostate cancer, lymphoma, colorectal cancer, kidney cancer, lung cancer, and melanoma.
The retroperitoneal region is located outside the peritoneal cavity, between the parietal peritoneum and the abdominal wall. The kidneys are anchored to the posterior abdominal wall by a tough renal fascia.
One specific retroperitoneal structure worth mentioning is the renal fat pad, which surrounds the kidneys and is enclosed by the renal fascia.