adenomatoid tumors

Adenomatoid tumor is a benign, relatively rare neoplasm occurring primarily in the genital tract of both genders.

Adenomatoid tumours most commonly arise in the genital tract, but occasionally occur in the pleura. They are small and solitary and usually discovered as incidental findings.

Histologically, they are composed of vacuolated epithelioid mesothelial cells forming tubular spaces.

Localization

 adenomatoid tumor of the epididymis
 adenomatoid tumor of the tunica albuginea
 adenomatoid tumor of the testicle
 adenomatoid tumor of the ovary
 adenomatoid tumor of the myometrium
 adenomatoid tumor of the fallopian tube
 adenomatoid tumor of the parafallopian region
 adenomatoid tumor of the mediastinum (14707875)
 adenomatoid tumor of the adrenal gland (14506647)
 pleural adenomatoid tumor

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