Most authors distinguish: (i) parapelvic cysts: originating in the renal parenchyma extending into, and primarily expanding within, the renal sinus, and (ii) peripelvic cysts: originating in sinus structures which presumably represent mostly lymphatic collections.
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A renal cyst is a fluid collection in or on the kidney. There are several types based on the Bosniak classification. The majority are benign, simple cysts that can be monitored and not intervened upon. However, some are cancerous or are suspicious for cancer and are commonly removed in a surgical procedure called nephrectomy.
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