Cystic lesions of the adrenal gland: our experience over the last 20 years.

Cystic lesions of the adrenal gland are uncommon, often presenting with nonspecific clinical and radiologic findings, and are thus underrecognized. They are occasionally associated with malignant neoplasms, which can greatly mimic benign lesions and carry detrimental clinical consequences if misdiagnosed. Here we present our 20-year experience (1992-2012) with these lesions at an academic medical center. Among more than 4500 adrenal gland specimens, 31 cases of adrenal lesions with a predominant cystic component were identified in 30 patients with an age range of 34 to 86 years (median, 55.5 years) and a male/female ratio of 13:17. Macroscopic descriptions, available histologic and immunostain slides, and available radiologic records were reviewed for all included cases. Radiologic studies and gross examination correlated well, and hemorrhage (26 cases; 84%) and encapsulation (25 cases; 81%) appeared to be nonspecific radiologic/gross features shared across histologic subtypes. Microscopic review identified 12 cases (39%) of pseudocysts, 2 cases (6%) of endothelium-derived cysts, and 17 cases (55%) of epithelium-derived cysts. Among these 31 cystic adrenal lesions, 2 cases (6%) were malignant neoplasms (1 epithelioid angiosarcoma, 1 adrenocortical carcinoma). Radiologic impression and histopathologic diagnosis were concordant in 11 (73%) of the 15 cases for which radiologic records were available. This study represents the second largest case series to date on cystic adrenal lesions and presents a comprehensive review on their demographic, clinical, radiologic, and gross and microscopic pathologic features, as well as their differential diagnoses.