%0 Journal Article %T Non-Neoplastic Thoracic Cysts: A Clinicopathologic Study of 136 Cases. %A Weissferdt A %J Am J Surg Pathol %V 47 %N 12 %D 2023 12 1 %M 37642507 %F 6.298 %R 10.1097/PAS.0000000000002115 %X Benign cysts of the thoracic cavity represent a group of rare lesions, the spectrum of which is expanding. Most of these are congenital in nature, secondary to abnormal development during embryogenesis while a smaller subset represents acquired lesions. We retrospectively reviewed the clinicopathologic features of 136 patients with thoracic cysts that were treated in our institution over a span of 20 years. The patients were 85 female and 51 male patients with an average age of 51 years. Eighty-four of the patients were asymptomatic (62%), the remainder mainly presented with chest pain, shortness of breath, or cough. Surgical resection was performed in 123 patients while 12 patients were treated with aspiration only and 1 underwent core biopsy. The cyst size ranged from 0.5 to 14.8 cm (mean, 4.4 cm); histologically, the lesions included 50 thymic cysts (28 multilocular; 22 unilocular), 37 bronchogenic cysts, 23 pleuropericardial cysts, 12 unclassified cysts, 6 Müllerian cysts, 5 enteric cysts, and 3 parathyroid cysts. Clinical follow-up revealed that 97 patients were alive and well 4 months to 37 years after initial diagnosis; 25 patients were lost to follow-up and 14 patients died of unrelated causes. The current study is one of the largest studies on the subject with emphasis on clinicopathologic characteristics. This series has a higher incidence of thymic cysts compared with prior publications and covers a wider spectrum of different histologic types than previously reported.