| Inbound Relationships | Type | Active | Source | Characteristic | Refinability | Group | 
| Periureteritis | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Pararenal urinoma | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Paraureteric urinoma | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Perirenal and periureteric post-transplant lymphocele | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Perinephritis | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Chronic peri-aortitis | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Peripancreatic hematoma | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of retroperitoneum | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of periadrenal tissue | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of perirenal tissue | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal lymphadenopathy | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal abscess | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal fibrosis | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Mass of retroperitoneal structure | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Benign neoplasm of retroperitoneum | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Primary malignant neoplasm of retroperitoneum | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of uncertain behavior of retroperitoneum | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal edema | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal hemorrhage | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal fat necrosis | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Cyst of retroperitoneal compartment | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Pneumoretroperitoneum | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Injury of retroperitoneum with open wound into abdominal cavity | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Injury of retroperitoneum without open wound into abdominal cavity | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Perirenal pseudocyst | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Retroperitoneal infection | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Cyst of retroperitoneal compartment | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of periadrenal tissue | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of perirenal tissue | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Neoplasm of uncertain behavior of retroperitoneum | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Contracture of iliopsoas | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Perirenal pseudocyst | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Malignant neoplasm of perinephric tissue | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Benign neoplasm of perinephric tissue | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Renal vascular disorder | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Lumbar lymphadenopathy | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Metastatic malignant neoplasm to retroperitoneal lymph nodes | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Acute inflammation of retroperitoneal lymph node | Is a | False | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  | 
| Pancreatic and peripancreatic necrosis | Is a | True | Disorder of retroperitoneal region, excluding major organs | Inferred relationship | Existential restriction modifier |  |