American Board of Pathology (ABPath) Practice Test 2025 - Free Pathology Exam Practice Questions and Study Guide

The most common cystic mass found in the spleen is indeed the acquired pseudocyst. Acquired pseudocysts often arise after an episode of splenic trauma or infarction, and they can be formed from fluid accumulation that develops in the spleen's tissue. Unlike true cysts, which have a defined epithelial lining, pseudocysts are characterized by their lack of such a lining, making them a collection of fluid surrounded by fibrous tissue. This feature is particularly relevant in the spleen, where trauma or infection can lead to the formation of these cystic collections.

In contrast, simple cysts and congenital cysts are generally much less common in the spleen. Simple cysts are usually asymptomatic fluid-filled sacs and are often congenital in nature, while congenital cysts generally refer to those present from birth. Hemangiomas are benign vascular tumors often found in the spleen, but they are more solid in nature and not classified as cystic masses. Therefore, the context of acquired pseudocysts being more frequently encountered after splenic injury or disease underscores its prevalence as the most common cystic mass in the spleen.