Tumor-infiltrating lymphocytes and histocompatibility antigens in primary intracranial germinomas

Case Report: From epilepsy and uterus didelphys to Turner syndrome-associated dysgerminoma

Dysgerminoma is a rare occurrence in Turner syndrome patients without Y chromosome mosaicism or hormone therapy during puberty. We present a unique case of a 33-year-old nulliparous Chinese woman with intermittent epilepsy and Mullerian anomalies carrying a double uterus, cervix, and vagina. The patient is also characterized as having Turner syndrome accompanied by 46,X, del(Xp22.33-11.23) and del(2)(q11.1-11.2). MRI exhibited a 17.0 cm × 20.0 cm × 10.5 cm solid ovarian lesion. Radical surgery and pathology revealed dysgerminoma at stage IIIc with lymphatic metastases and a KIT gene mutation identified in exon 13. Furthermore, the tumor microenvironment (TME) displayed robust expression of CD4+ T lymphocytes and PD-1, whereas the distribution of CD8+ T lymphocytes and PDL-1 was sporadic. Despite the administration of enoxaparin to prevent thromboembolism, the patient experienced multiple cerebral infarctions during chemotherapy. Subsequently, the patient chose to decline further treatment and was discharged. This exceptional case imparts several noteworthy lessons. First, the coexistence of Mullerian anomalies, although rare, is not incompatible with Turner syndrome. Second, screening for KIT mutations is imperative to reduce the risk of dysgerminoma in Turner syndrome, especially for patients with Y mosaicism who are recommended for hormone replacement therapy. Lastly, comprehensive anticoagulation therapy is crucial for Turner syndrome patients undergoing cisplatin-based chemotherapy.

PD-1/PD-L1 expression in a series of intracranial germinoma and its association with Foxp3+ and CD8+ infiltrating lymphocytes

One histopathological characteristic of intracranial germinoma is abundant tumor-infiltrating lymphocytes (TILs) showing a two-cell pattern with large undifferentiated tumor cells. The programmed cell death 1 (PD-1)/programmed cell death 1 ligand (PD-L) axis has recently been recognized as an anti-tumor immune system. To evaluate intratumor immune status in intracranial germinoma, we examined expressions of PD-1 and PD-L1 (clone 28-8) and subtypes of TILs. Expressions of PD-1 and PD-L1 were detected immunohistochemically in 25 formalin-fixed, paraffin-embedded tumor specimens from 24 patients with intracranial germinoma consisting of 22 primary and 3 recurrent tumors. To evaluate subtypes of TILs, quantification of lymphocytes with CD3, CD8, CD4, and Foxp3 was performed. Statistical analyses were performed among PD-1, PD-L1 and subtypes of TILs. In 25 tumor tissue, expressions of PD-1 in TILs and PD-L1 in tumor cells were identified in 96% (24/25) and 92% (23/25), respectively. Expression of PD-1 was associated with CD3+ TIL density. Expression of PD-1 correlated with Foxp3+ TIL density and CD8+ TIL density, but not with CD4+ TIL density. Furthermore, expression of PD-1 correlated strongly with Foxp3+/CD4+ ratio. Taken together, increase of PD-1+ expression is associated with accumulation of Foxp3+ and CD8+ TILs. These findings intimate that PD-1/PD-L1 axis might shape the immune infiltration suggesting a modulation of the immune response and subsequent tumor growth in intracranial germinoma. Anti-PD-1 and anti-PD-L1 are potential immune therapeutic strategies in intracranial germinoma.

Genome-wide methylation profiles in primary intracranial germ cell tumors indicate a primordial germ cell origin for germinomas

Intracranial germ cell tumors (iGCTs) are the second most common brain tumors among children under 14 in Japan. The World Health Organization classification recognizes several subtypes of iGCTs, which are conventionally subclassified into pure germinoma or non-germinomatous GCTs. Recent exhaustive genomic studies showed that mutations of the genes involved in the MAPK and/or PI3K pathways are common in iGCTs; however, the mechanisms of how different subtypes develop, often as a mixed-GCT, are unknown. To elucidate the pathogenesis of iGCTs, we investigated 61 GCTs of various subtypes by genome-wide DNA methylation profiling. We showed that pure germinomas are characterized by global low DNA methylation, a unique epigenetic feature making them distinct from all other iGCTs subtypes. The patterns of methylation strongly resemble that of primordial germ cells (PGC) at the migration phase, possibly indicating the cell of origin for these tumors. Unlike PGC, however, hypomethylation extends to long interspersed nuclear element retrotransposons. Histologically and epigenetically distinct microdissected components of mixed-GCTs shared identical somatic mutations in the MAPK or PI3K pathways, indicating that they developed from a common ancestral cell.

Pituitary and systemic autoimmunity in a case of intrasellar germinoma

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient's serum recognized antigens expressed by the patient's own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis.

Immunohistochemical characterization of 'small, lymphoid-like cell populations' within germinomas: immunologic and molecular approaches to diagnosis

Little is known to date about the biological and molecular characteristics of 'small lymphoid cells' within intracranial germinomas. Frozen sections from three germinoma specimens were evaluated immunohistochemically in order to identify phenotypic markers expressed on human lymphoid cells as well as intercellular adhesion molecules. In addition, T-cell receptor (TCR) variable alpha- and beta-chain mRNA expression was analyzed by polymerase chain reaction (PCR). The small cells stained faintly with anti-CD5 in two specimens, but were negative for the T cell specific markers, CD2, CD3, CD7, and CD8. In addition, these cells were weakly positive for CD11b (Mac-1) and CD54 (ICAM-1), but were negative for lymphocyte-specific CD11a (LFA-1) and CD11c (p150,95). No TCR V alpha or V beta gene expression was detected by PCR within these germinoma specimens. The small cells of germinomas with the cytologic appearance of lymphocytes are not derived from T-cells or other lymphocytic lineages.

Complete disappearance of giant intracranial germinoma after irradiation

Intracranial germinomas are lesions with a varying, rather benign growth potential, and account for only 0.3 to 1.5% of all brain tumors. About 70% of the patients with these tumors are between 10 and 21 years of age at diagnosis. Germinomas are radiosensitive and respond well also to chemotherapy. The case of a 22-year-old male patient with a giant primary intracranial germinoma originating in the pineal region is presented. Clinical signs and symptoms are described together with neuroradiological, light-microscopic, and immunohistochemical findings. The tumor was irradiated with a total dose of 46 Gy and disappeared completely already after an effective tumor dose of 30 Gy. No recurrence was seen during a follow-up of three years. The patient's quality of life could be preserved and a complete cure was achieved.

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.

Immunohistochemical study of natural killer cells in tumor-infiltrating lymphocytes of primary intracranial germinomas

A monoclonal antibody against the surface marker IOT-10 of natural killer (NK) cells was used to investigate the presence and distribution of these cells in a series of nine primary intracranial germinomas. In all of these tumors, IOT-10-positive NK cells were found in small numbers, mainly distributed among the tumor cells. The data obtained in the present study suggest that the presence of NK cells in primary intracranial germinomas can be influenced by factors other than the mere quantity of tumor-infiltrating lymphocytes.

An immunohistochemical analysis of T cells in primary B cell malignant lymphoma of the brain

An immunohistochemical study was performed on small lymphoid cells present in frozen tissue sections of seven cases of primary B cell malignant lymphomas of the brain by using monoclonal antibodies to T cell (Leu-1, OKT-11, Leu-3a, and Leu-2a) and B cell (BA-1 and Leu-12) surface markers. In all the seven cases, positive reaction for Leu-1 and OKT-11 was seen in the majority of the small lymphoid cells which were dispersed among the lymphoma cells or clustered around blood vessels. The large neoplastic cells were unstained by these antibodies. Staining for T cell subsets with antibodies to Leu-3a and Leu-2a showed heterogeneous staining in each case. The ratio of Leu-3a+ to Leu-2a+ cells was less than one in six cases, demonstrating a suppressor/cytotoxic phenotype predominance. Most of these small lymphoid cells were negatively stained by antibodies to BA-1 and Leu-12. From these findings, it was shown that the small lymphoid cells observed in primary B cell lymphomas of the brain were of T cell lineage, distinct from the neoplastic cells, and probably reactive in nature. The implications of these findings are discussed.