Non-neoplastic adrenal pseudocysts: A clinicopathologic study of 44 cases with potential insights into pathogenesis

Literature on non-neoplastic adrenal pseudocysts (NNAPC) remains limited and to date no large series have been reported. The pathogenesis of these lesions remains poorly defined, however a vascular origin is most often suggested in the literature. We aimed to evaluate the clinicopathological features and the spectrum of vascular changes within NNAPC, in order to better understand the mechanisms and circumstances of their pathogenesis. We reviewed 44 cases of surgically resected NNAPC. There were 30 females and 14 males ranging from 23 to 82 years (median, 53 years). On the basis of histopathologic and immunohistochemical analysis of the vascular changes the following types were defined: pseudocysts with lymphatic-related changes (type 1, n = 16), pseudocysts with large vein-related changes (type 2, n = 15) and pseudocysts with blood vessel microvasculature-related changes (type 3, n = 13). The median patient age of the latter group was higher than that of type 1 and 2 (64 years versus 51 and 50 years, respectively; p = 0.0002). Type 3 pseudocysts were more frequently associated with a history of systemic vascular and vascular-related disorders than type 1 and type 2 pseudocysts (92% versus 33% and 64%, respectively; p = 0.008). Type 1 pseudocysts were more frequently connected with a history of previous intra-abdominal surgical procedures than type 2 and 3 pseudocysts (60% versus 7% and 25%, respectively; p = 0.0079). NNAPC are clinically heterogenous and can arise on a background of various vascular changes. They may represent end-stage processes related to lymphangiomatous lesions, changes in adrenal venous structures or microvasculature. •We evaluated the clinicopathological features of a large series of non-neoplastic adrenal pseudocysts (NNAPC).•On the basis of histopathologic and immunohistochemical analysis of vascular changes, 3 types of pseudocysts were defined•NNAPC most commonly represent end-stage processes related to adrenal lymphangiomatous lesions•They may also form secondary to changes in adrenal venous structures or blood vessel microvasculature•NNAPC are clinically heterogenous lesions forming on a background of various types of vascular changes