Robot-Assisted Thoracoscopic Resection of a Posterior Mediastinal Mullerian Cyst

Figure 2

(a) 4-micron, H&E-stained, formalin-fixed, paraffin-embedded sections at 20x demonstrate a simple cystic lining with no epithelial complexity, bland fibrous tissue, and no significant associated inflammation or hemorrhage

(b) Immunohistochemical stain for estrogen receptor reveals diffuse nuclear positivity of most lining epithelial cells (immunoperoxidase, 200x)

(c) 600x H&E shows simple Mullerian tubal-type columnar epithelium with mostly secretory cells and some ciliated cells

(d) 100x 4-micron formalin-fixed paraffin-embedded sections stained with PAX8 immunoperoxidase preparation highlights diffuse epithelial nuclear reactivity with the PAX8 antibody, confirming Mullerian differentiation