GLIOMATOSIS PERITONEI COMBINED WITH MATURE OVARIAN TERATOMA - IMMUNOHISTOCHEMICAL OBSERVATIONS

Gliomatosis peritonei (GP) is the metastatic implantation of glial cel ls within the peritoneal cavity of patients with ovarian teratomas. Th e case of a young woman is presented who initially developed a mature teratoma in the left ovary that was surgically removed. Nine years lat er a mature teratoma in the right ovary was excised: upon which GP was found in the greater omentum. To identify the cellular composition of the ovarian teratoma and of the omental implants, immunostainings wer e performed using antibodies against glial and neuronal antigens as we ll as against determinants of hematopoietic cells. In the teratoma the neuroectodermal part was strongly HNK-1-positive and contained GFAP- and vimentin-positive astrocytes and some NSE-positive neuron-like cel ls. In addition, neuroectodermal tissue was infiltrated by numerous CD 68-positive macrophages/histiocytes and CD20-positive B lymphocytes. T he omental nodules consisted of astrocytes, which expressed GFAP, vime ntin and desmin. The implants also contained macrophages/histiocytes, which exhibited morphologic features reminiscent of microglial cells. In GP, macrophages might release glia-promoting trophic factors, which could allow the neural component of ovarian teratoma to implant in th e peritoneal cavity and survive there for many years. Macrophage-deriv ed factors might induce astroglial differentiation, which could explai n why the peritoneal implants are mostly mature even when they origina te from immature teratomas.