Figure 1

Pseudocyst. Pseudocyst is defined by the lack of an epithelial lining. The constituents of the wall vary depending on the stage of the lesion; in the earlier phase, necrotic debris and precipitated acinar secretions are present in the lumen, and granulation tissue on the wall. Later on, fibrosis becomes more prominent. In this example, histiocytes are prominent adjacent to the lumen of the cyst, and there is a cellular stroma around it. This can mimick ovarian-type stroma of mucinous cystic neoplasms.