Diffuse embryoma of the testis. An immunohistochemical study of two cases

A Precious Diagnostic "Pearl": The Necklace Pattern in Germ Cell Tumors of the Testis

Diffuse embryoma is a rare pattern of nonseminomatous germ cell tumor of the testis originally described in 1983. We report a case with this predominant pattern in an 18-year-old male with a painless palpable testicular mass. Although it is relatively common to see a diffuse embryoma pattern focally in mixed nonseminomatous germ cell tumors of the testis, it is rarely the predominant pattern and can represent a diagnostic pitfall on routine hematoxylin and eosin stain. We emphasize the importance of recognizing the individual components within the diffuse embryoma pattern, review the literature, and briefly discuss the ancillary immunohistochemical stains that may be utilized to help support the diagnosis.

Potential application and prevalence of the CD30 (Ki-1) antigen among solid tumors: A focus review of the literature

BACKGROUND

CD30 (Ki-1) is a cell membrane protein derived from the tumor necrosis factor (TNF) receptor family. The CD30 antigen has been associated primarily with Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL). Brentuximab vedotin (BV) is an antibody-drug conjugate targeting the CD30 antigen. FDA approval for BV includes relapsed and refractory HL and sALCL. The CD30 antigen also has been identified in many solid tumors, predominantly of germ cell origins and early clinical data is promising.

OBJECTIVE

Perform a focus literature review evaluating the prevalence of the CD30 antigen among nonlymphomatous tumors with a potential correlate for CD30 targeted therapy.

ELIGIBILITY CRITERIA

Inclusion criteria: all retrospective reviews and case reports citing CD30 positivity or negativity in non-lymphomatous malignancies in which data were presented based on location.

EXCLUSION CRITERIA

studies with hematopoetic malignancies, cutaneous malignancies, non-human populations, and non-english publications.

INCLUDED STUDIES

A total of 119 articles met these criteria and are summarized in this manuscript.

CONCLUSION

The CD30 antigen has shown variable prevalence among non-hematopoetic tumors, most notably among germ cell tumors and mesothelioma. With additional, preclinical and properly powered clinical studies, CD30 targeted therapy such as that of BV, alone or in combination with other agents may prove to be a strong candidate in the treatment of various CD30⁺ malignancies.

Oncofetal protein glypican-3 in testicular germ-cell tumor

The expression of an oncofetal protein, the glypican-3 (GPC3), was immunohistochemically evaluated in a wide variety of primary testicular germ-cell tumors (GCTs) in comparison with other markers, alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG)-beta, and OCT3/4. Eighty-nine cases of GCT including 22 cases of mixed GCT were evaluated with reference to each tumor component. GPC3 expression was observed in neoplastic cells of yolk-sac tumor (YST) (25/25), teratoma (2/10), components of syncytiotrophoblastic giant cells (STGCs) (10/14), and choriocarcinoma (1/3), but none in intratubular germ-cell neoplasias, unclassified type (0/33), seminomas (0/61), or embryonal carcinoma (0/19). All cases of YST showed diffuse labeling of neoplastic cells in cytoplasmic and membranous patterns, and the positive area of GPC3 was much larger than that of AFP. Glandular structures in teratomas showed GPC3 immunostaining as well as AFP. Although the number of GPC3-positive cells was smaller in STGC components and choriocarcinoma, there was no diffusion artifact in GPC3 immunostaining, as was frequently encountered in hCG-beta staining. Thus, GPC3 is a unique oncofetal protein, which is useful as an immunohistochemical marker for GCT differentiated to extraembryonic tissue, especially YST.

Ber-H2 (CD30) immunohistochemical staining of human fetal tissues

OBJECTIVE: CD30 antigen has long been considered to be restricted to the tumour cells of Hodgkin's disease and of anaplastic large cell lymphoma as well as to T and B activated lymphocytes. It is now apparent that the range of normal and neoplastic cells, which may express CD30 antigen, is much wider than was at first thought. In order to gain insight into the physiological function of CD30 antigen, we studied the distribution of its expression in the tissues of fetuses from week 8^th to week 16^th.

MATERIALS AND METHODS: We investigated the immunohistochemical expression of CD30 antigen in paraffin-embedded tissue samples representing all systems from 30 fetuses after therapeutic abortion at 8^th to 10^th and 12^th to 16^th week of gestation, respectively, using the monoclonal antibody Ber-H2.

RESULTS: Our results demonstrated that CD30 is expressed early in human fetal development (8^th to 10^th week of gestation) in several fetal tissues derived from all three germ layers (gastrointestinal tract, special glands of the postpharyngeal foregut, urinary, musculoskeletal, reproductive, nervous, endocrine systems), with the exception of the skin and hematolymphoid system (thymus), in which the antigen is expressed later on (10^th week onwards). Expression of CD30 was restricted to the hematolymphoid system in the 12-16 weeks of gestation. No expression of the marker was observed in the respiratory and cardiovascular systems during the entire period examined.

CONCLUSIONS: CD30 antigen is of importance in cell development, and proliferation. It is also pathway-related to terminal differentiation in many fetal tissues and organs.

Human embryonal epithelial cells of the developing small intestinal crypts can express the Hodgkin-cell associated antigen Ki-1 (CD30) in spontaneous abortions during the first trimester of gestation

BACKGROUND

Ki-1 (CD30) antigen expression is not found on peripheral blood cells but its expression can be induced in vitro on T and B lymphocytes by viruses and lectins. Expression of CD30 in normal tissues is very limited, being restricted mainly to a subpopulation of large lymphoid cells; in particular, cells of the recently described anaplastic large cell lymphoma (ALCL), the Reed-Sternberg (RS) cells of Hodgkin's lymphoma and scattered large parafollicular cells in normal lymphoid tissues. More recent reports have described CD30 expression in non-hematopoietic and malignant cells such as cultured human macrophages, human decidual cells, histiocytic neoplastic cells, mesothelioma cells, embryonal carcinoma and seminoma cells.

RESULTS

We investigated the immunohistochemical expression of CD30 antigen in 15 paraffin-embedded tissue samples representing small intestines from fetuses after spontaneous abortion in the 8th, 10th and 12th weeks using the monoclonal antibody Ki-1. Hormones had been administered to all our pregnant women to support gestation. In addition, a panel of monoclonal antibodies was used to identify leukocytes (CD45/LCA), B-lymphocytes (CD20/L-26) and T-lymphocytes (CD3). Our findings were correlated with those obtained simultaneously from intestinal tissue samples obtained from 15 fetuses after therapeutic or voluntary abortions.

CONCLUSIONS

The results showed that: (1) epithelial cells in the developing intestinal crypts express the CD30 (Ki-1) antigen; (2) CD30 expression in these epithelial cells is higher in cases of hormonal administration than in normal gestation. In the former cases (hormonal support of gestation) a mild mononuclear intraepithelial infiltrate composed of CD3 (T-marker)-positive cells accompanies the CD30-positive cells.

Testicular mixed germ cell tumor with polyembryoma component in brothers

We report the case of a 17-year-old male with a testicular tumor and high serum levels of alpha-fetoprotein. The patient was treated with surgery followed by combination chemotherapy with bleomycin, etoposide, and cisplatin. Histologic examination showed features of a mixed germ cell tumor composed of mature teratoma, immature teratoma, embryonal carcinoma, yolk sac tumor, and polyembryoma. He is currently well, and his serum levels of alpha-fetoprotein have been normal more than 5 months after treatment. His brother, aged 17 years at the time, had a similar tumor removed from the right testicle 5 years previously.

Expression of the CD30 antigen in non-lymphoid tissues and cells

Originally, expression of the CD30 antigen was shown to be typical of the tumour cells of Hodgkin's disease (HD) and of anaplastic large cell lymphomas (ALCLs). In reactive lymphoid tissue, CD30 is expressed only in a small population of activated lymphoid blasts. Since then, several reports have been published describing CD30 expression in non-lymphoid tissues and malignancies, such as embryonal carcinomas (ECs), seminomas, cultivated macrophages, two histiocytic neoplasms, decidual cells, and mesotheliomas. As CD30 detection is important in the differential diagnosis of HD and ALCL, the expression of CD30 in different non-lymphoid tissues was re-evaluated by immunohistology and in situ hybridization. Extra-lymphoid CD30 expression was found in 48/51 cases of EC or EC components of germ cell tumours, in decidual cells of 1/10 cases, in activated mesothelium in 16/28 pleural and peritoneal effusions, and in small foci of tumour cells in 2/8 mesotheliomas. CD30 expression was not confirmed in 27 germ cell tumours of the testis without an EC component nor in cultivated macrophages and 17 histiocytic malignancies. The knowledge of these CD30 expression patterns is important for the immunohistological differential diagnosis of anaplastic tumours. The absence of CD30 expression in reactive and neoplastic macrophages does not favour the concept that HD and ALCL are derived from these cells.