E2092. Perirenal Lymphatics: Anatomy, Pathophysiology, and Imaging Spectrum of Diseases
  1. Jeffrey Guccione; The University of Texas Health Sciences Center
  2. Christine Menias; Mayo Clinic
  3. Akram Shaaban; University of Utah
  4. Corey Jensen; MD Anderson Cancer Center
  5. Ajaykumar Morani; MD Anderson Cancer Center
  6. Khaled Elsayes; MD Anderson Cancer Center
The perirenal and intrarenal lymphatics are rarely taught or discussed but play an important role in the pathogenesis of many renal and perirenal diseases. Although these lymphatics follow the general architecture of the vasculature, they have unique features and communication, directing the spread of disease, especially malignancy. Their small size makes direct imaging difficult but they may be seen indirectly as a result of pathology. Therefore, understanding of lymphatic anatomic form and function is helpful in recognition and diagnosis of several renal and perirenal disease processes.

Educational Goals / Teaching Points
The renal and perirenal lymphatic anatomy is important for understanding how diseases involve and spread to the perirenal space. Evaluation of perirenal pathology can be performed with a number of imaging techniques and it’s important to understand the benefits and limitations of each. These lymphatics themselves are occasionally indirectly seen on imaging, but several techniques may aid in direct visualization. A wide range both neoplastic and non-neoplastic pathology can involve the renal lymphatics and understanding their imaging features helps create a relevant differential and an accurate diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
The intrarenal and perirenal lymphatics are involved and implicated in a large number of disease processes. Several are benign and are a result of lymphatic malformation or dysfunction, such as peripelvic cysts and lymphangiomatosis. Many of these have specific imaging features, which are thoroughly detailed, and appearances as a result of the lymphatic involvement. For example, perinephric stranding is a manifestation of intestinal fluid and dilated lymphatics. The standing can be smooth, seen in the setting of infectious or inflammation disorders, or nodular, present with metastasis or malignancy. Although these lymphatics are occasionally indirectly seen, direct imaging is difficult, and has only recently been described with new techniques on MRI.

Although usually ignored in discussing renal and perirenal pathology, the lymphatics are involved in a wide range of both neoplastic and non-neoplastic processes. These include lymphangiomatosis, metastasis, lymphoma, and leukemia, to name a few. A thorough understanding of these diseases and the lymphatic involvement is crucial to create a relevant differential and an accurate diagnosis.