Paraovarian cysts likely arise from vestigial remnants of the mesonephric and paramesonephric ducts. Paraovarian cysts are not connected to the ovary; they are adjacent to the ovary in the mesovarium or mesosalpinx (Figure 1, Figure 2, Figure 3 and Figure 4). Paraovarian cysts are lined by flattened, cuboidal or columnar epithelium, and the epithelium may be ciliated. A connection to paraovarian structures in the mesovarium may be seen. The presence of smooth muscle in the wall of the cyst is variable.
Paraovarian cysts should be diagnosed, but cysts occurring as background lesions need not be graded. In the case of paraovarian cysts, the diagnosis should include the type of cyst/location as a modifier (i.e., Ovary, Paraovarian tissue - Cyst). If the cysts are thought to be treatment related, they may be graded to fully characterize the treatment effect. If applicable, the terms "bilateral" and "multiple" may be included in the diagnosis.
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