Dysgerminoma of the ovary. An immunohistochemical study of tumor-infiltrating lymphoreticular cells and tumor cells.

BACKGROUND

Human neoplasms often are accompanied by an inflammatory infiltrate. It has been proposed that this represents an immunologic response to the tumor. Dysgerminoma, a germ cell tumor of the ovary, is a classic example of this phenomenon. The authors investigated the immunophenotype of the tumor-infiltrating lymphoreticular cells (TIL) and tumor cells in this rare malignancy.

METHODS

Tissue from seven dysgerminomas of the ovary was fixed in formaldehyde solution and embedded in paraffin and investigated immunohistochemically with a broad panel of monoclonal antibodies. In one case, additional immunohistochemical investigations were performed on cryopreserved tumor tissue.

RESULTS

All seven tumors showed a marked cellular stromal reaction with formation of disseminated granulomas similar to that seen in the closely related testicular seminoma. The TIL were preponderantly T-cells (CD43+, CD45RO+, OPD4+) and macrophages/epithelioid cells (MAC387+, CD68+), B-cells (CD20+, Ki-B3+), natural killer cells (CD57+), and immune-accessory cells (CD1+, CD35+) were rare in most cases. In the one case in which cryopreserved tissue was available, most of the intratumoral T-cells belonged to the CD8+ (cytotoxic/suppressor) subtype, and most of the intratumoral T-cells expressed the alpha/beta heterodimer of the T-cell antigen receptor; gamma/delta + T-cells were exceedingly rare. Some of the macrophages/epithelioid cells were found to express activation antigens (interleukin-2 receptor, transferrin receptor, HLA-DR2). Antibodies against placental alkaline phosphatase and pancytokeratin each stained tumor cells in six cases. Virtually no tumor cells were found to express major histocompatibility complex (MHC) Class II antigens.

CONCLUSIONS

The immunohistochemical findings concerning the tumor cells and TIL in dysgerminoma of the ovary provide additional evidence of a close relation to seminoma of the testis.