Pediatric renal and adrenal masses

Abstract

Retroperitoneal tumors arising from the kidneys and adrenal glands are among the most common neoplasms in children. Ultrasound is typically the first imaging modality used, and provides valuable diagnostic information without ionizing radiation. While ultrasound findings are often non-specific, knowing the patient’s age along with certain imaging characteristics allows reasonable diagnostic clarity. More importantly, ultrasound allows assessment of vascular invasion or encasement, intra-abdominal extent and involvement of contralateral structures, and vital information for surgical management. This lecture will focus on the sonographic diagnosis of retroperitoneal tumors, as well as their demographics and biological behaviors. Wilm’s tumor is the most common pediatric renal neoplasm, and requires careful evaluation of vascular structures and the opposite kidney. Nephroblastomatosis often coexists with Wilm’s tumors, with characteristically distributed hypoechoic masses. Mesoblastic nephroma is the most common solid renal neoplasm of newborns, with imaging features not distinguishable from Wilm’s tumor. Similarly, multilocular cystic nephroma cannot be reliably differentiated from a cystic Wilm’s tumor by imaging alone. Renal cell carcinoma, clear cell sarcoma, and rhabdoid tumors are uncommon pediatric neoplasms, which will be briefly discussed. Renal lymphoma can produce a variety of sonographic appearances, which are important to recognize as this is one of the few non-surgical renal mass lesions. Neuroblastoma is the most common adrenal neoplasm in the younger child, and can usually be diagnosed from its characterisitc vascular encasement, site of origin, and calcifications. Adrenal cortical neoplasms are less common, and are usually suspected from patient symptoms. Retroperitoneal tumors arising from the kidneys and adrenal glands are among the most common neoplasms in children. Ultrasound is typically the first imaging modality used, and provides valuable diagnostic information without ionizing radiation. While ultrasound findings are often non-specific, knowing the patient’s age along with certain imaging characteristics allows reasonable diagnostic clarity. More importantly, ultrasound allows assessment of vascular invasion or encasement, intra-abdominal extent and involvement of contralateral structures, and vital information for surgical management. This lecture will focus on the sonographic diagnosis of retroperitoneal tumors, as well as their demographics and biological behaviors. Wilm’s tumor is the most common pediatric renal neoplasm, and requires careful evaluation of vascular structures and the opposite kidney. Nephroblastomatosis often coexists with Wilm’s tumors, with characteristically distributed hypoechoic masses. Mesoblastic nephroma is the most common solid renal neoplasm of newborns, with imaging features not distinguishable from Wilm’s tumor. Similarly, multilocular cystic nephroma cannot be reliably differentiated from a cystic Wilm’s tumor by imaging alone. Renal cell carcinoma, clear cell sarcoma, and rhabdoid tumors are uncommon pediatric neoplasms, which will be briefly discussed. Renal lymphoma can produce a variety of sonographic appearances, which are important to recognize as this is one of the few non-surgical renal mass lesions. Neuroblastoma is the most common adrenal neoplasm in the younger child, and can usually be diagnosed from its characterisitc vascular encasement, site of origin, and calcifications. Adrenal cortical neoplasms are less common, and are usually suspected from patient symptoms.