Localization

 epididymis
 tunica albuginea
 testicule
 ovary
 myometrium
 fallopian tube
 parafallopian region
 mediastinum (#14707875#)
 adrenal gland (#14506647#)

Synopsis

 cystic spaces lined by flattened or cuboidal epithelial cells
 walls of the cysts: proliferation of small canalicular structures lined by round to polygonal epithelioid cells with vacuolated eosinophilic cytoplasm
 +/- infarction (#14707867#)
 fibrous tissue
 numerous slit-like and pseudotubular spaces
 thread-like bridging strands crossing the pseudotubular spaces (#14571427#)

Immunohistochemistry

 AE1/AE3 cytokeratin+
 CK5/CK6 cytokeratin+
 calretinin+
 CK7-
 CK20-
 alpha-fetoprotein-
 CD31-
 carcinoembryonic antigen-
 MOC-31-
 chromogranin-

Electron microscopy

 numerous long microvilli on the cell surface and abundant tonofilaments/desmosomal plaques in the tumor cells, characteristic of mesothelial cells