Perinatal (fetal and neonatal) germ cell tumors

Neoplasias neonatales: experiencia de un centro

INTRODUCTION

Malignant tumors are uncommon in the neonatal period and benign tumors may have malignant potential.

OBJECTIVES

To describe the neoplasms diagnosed and treated in newborns (</= 28 days of life) in the Hospital Universitario de Canarias and their association with congenital abnormalities and to evaluate prenatal diagnosis of these tumors.

PATIENTS AND METHODS

The medical records of patients with neoplasms diagnosed during the neonatal period in the previous 25 years in our hospital were retrospectively reviewed. The variables analyzed were the percentage of neonatal neoplasms among the total number of cancer cases in children aged less than 14 years, their incidence among all the newborns in our hospital, sex, year of diagnosis, age at clinical diagnosis, the presence or absence of prenatal diagnosis, type of tumor (histologic diagnosis), association with syndromes or other congenital anomalies, treatment, and long-term outcome.

RESULTS

Of 260 neoplasms diagnosed in our unit from 1980, 16 (6.1 %) were diagnosed in the neonatal period. The incidence of neonatal neoplasms was estimated to be 276.5 per million live births. Males accounted for 43.8 % and females for 56.2 %, with a mean age at diagnosis of 5.5 days (range 1-28 days). Five neonates (31.2 %) had a prenatal diagnosis, 60 % of which were made in the last 7 years of the study period. A further five newborns were diagnosed at the initial neonatal examination. Histologic diagnoses were neuroblastoma (n = 5; 31.2 %), teratoma/ germ cell tumor (n = 4; 25 %), soft tissue sarcoma (one fibrosarcoma of the thigh and two hemangiopericytoma of the back and heart; 18.8 %), and one case each of mesoblastic nephroma, cerebral tumor (ependymoblastoma), melanoma (associated with giant congenital melanocytic nevi), and acute leukemia (associated with Down syndrome). Treatment consisted of surgery alone (n = 10; 62.5 %) and surgery plus chemotherapy (n = 5; 31.2 %); one patient received no treatment. The overall actuarial survival rate was 87.5 %. Sequelae were observed in 33.3 % of survivors.

CONCLUSIONS

The neoplasms most frequently diagnosed in the neonatal period were solid tumors, mainly neuroblastoma and teratomas/germ cell tumors; 12.5 % were associated with syndromes or congenital anomalies. In the last 7 years, the prenatal diagnosis of these entities has improved. Most of the neoplasms responded to therapy, mainly surgery, and long-term outcome was favorable.

Complement-dependent control of teratoma formation by embryonic stem cells

The fetus has pluripotent stem cells that when transferred to mature individuals can generate tumors. However, for reasons yet unknown, tumors form rarely in the fetus and/or the mother during normal gestation. We questioned whether the complement system might protect against tumor formation by pluripotent stem cells. Murine embryonic stem cells were notably more susceptible than cardiomyocytes differentiated from those cells to lysis by complement in heterologous and homologous sera. Treatment of embryonic stem cells with heterologous serum averted tumor formation after residual cells were transplanted into mice. Confirming the importance of homologous complement in preventing formation of tumors, untreated embryonic stem cells formed tumors more quickly in C3-deficient than in wild-type mice. Susceptibility of embryonic stem cells to complement required an intact alternative pathway and was owed at least in part to a relative deficiency of sialic acid on cell surfaces compared with differentiated cells. Susceptibility to complement and resistance to tumors was inversely related to the number of cells transferred. These findings show that formation of tumors from embryonic stem cells is controlled in part by the alternative pathway of complement and suggest that susceptibility to complement might represent a general property of pluripotent stem cells that can be exploited to prevent tumor formation.

Factors associated with recurrence and metastasis in sacrococcygeal teratoma

Background

Sacrococcygeal teratoma (SCT) is a relatively uncommon tumour, with a high risk of recurrence and metastasis. The factors associated with recurrence and metastatic disease were studied.

Methods

A retrospective review was conducted of 173 children with SCT treated between January 1970 and February 2003 at the paediatric surgical centres in the Netherlands. Risk factors were identified by univariate and multivariate analysis.

Results

Eight children died shortly after birth or around the time of operation. Nine children, all over 18 months old, had metastases at presentation. Four teratomas with metastasis showed mature histology of the primary tumour. Nineteen children had recurrence of SCT a median interval of 10 months (range 32 days to 35 months) after primary surgery. Risk factors for recurrence were pathologically confirmed incomplete resection (odds ratio (OR) 6·54 (95 per cent confidence interval (c.i.) 2·11 to 20·31)), immature histology (OR 5·74 (95 per cent c.i. 1·49 to 22·05)) and malignant histology (OR 12·83 (95 per cent c.i. 3·27 to 50·43)). Size, Altman classification, age and decade of diagnosis were not risk factors for recurrence. One-third of the recurrences showed a shift towards histological immaturity or malignancy, compared with the primary tumour. Seven patients died after recurrence, five with malignant disease.

Conclusion

This national study showed that SCT recurred in 11 per cent of the children within 3 years of operation. Risk factors were immature and malignant histology, or incomplete resection. Mature teratoma has the biological capability to become malignant.

Pediatric presacral masses

Various types of masses may affect the presacral area in children. A presacral mass may be congenital or developmental or may arise from inflammation. The mass may have neural, vascular, lymphatic, or mesenchymal origins and may be primary (as in focal disease) or systemic (as in multifocal disease). Because the clinical manifestations of presacral masses are often nonspecific, imaging plays an important role in the detection and differentiation of these masses. Information obtained from imaging is also critical for management, especially for surgical planning. For these reasons, it is important that radiologists be familiar with the anatomy of the presacral region and with the imaging features of the various lesions that may occur in this region in children. For the accurate interpretation of findings, radiologists also must know the specific advantages and limitations of each of the imaging modalities used to evaluate this category of abnormalities.

Pluripotent stem cells and their niches

The ability of stem cells to self-renew and to replace mature cells is fundamental to ontogeny and tissue regeneration. Stem cells of the adult organism can be categorized as mono-, bi-, or multipotent, based on the number of mature cell types to which they can give rise. In contrast, pluripotent stem cells of the early embryo have the ability to form every cell type of the adult body. Permanent lines of pluripotent stem cells have been derived from preimplantation embryos (embryonic stem cells), fetal primordial germ cells (embryonic germ cells), and malignant teratocarcinomas (embryonal carcinoma cells). Cultured pluripotent stem cells can easily be manipulated genetically, and they can be matured into adult-type stem cells and terminally differentiated cell types in vitro, thereby, providing powerful model systems for the study of mammalian embryogenesis and disease processes. In addition, human embryonic stem cell lines hold great promise for the development of novel regenerative therapies. To fully utilize the potential of these cells, we must first understand the mechanisms that control pluripotent stem cell fate and function. In recent decades, the microenvironment or niche has emerged as particularly critical for stem cell regulation. In this article, we review how pluripotent stem cell signal transduction mechanisms and transcription factor circuitries integrate information provided by the microenvironment. In addition, we consider the potential existence and location of adult pluripotent stem cell niches, based on the notion that a revealing feature indicating the presence of stem cells in a given tissue is the occurrence of tumors whose characteristics reflect the normal developmental potential of the cognate stem cells.

Teratomas of the neck and mediastinum in children

This retrospective study reviews a series of teratomas of the neck and mediastinum aiming at defining the features of these particular locations. We recorded prenatal diagnosis, perinatal management, clinical and radiologic features, pathology, surgical strategies and results in cervical and mediastinal teratomas treated over the last 10 years. During this period we treated 66 children with teratoma of which 11 (6 male and 5 female) had cervicomediastinal locations. Five babies had cervical teratomas extended into the anterior mediastinum in two cases. Prenatal diagnosis was made in three (two with polyhydramnios). Four babies were born by C-section and only one had a successful EXIT procedure. The diagnosis was confirmed by imaging and increased AFP. Surgical treatment involved total tumor removal and in one case subsequent removal of lymph node metastases. All children survived except one in whom airway could not be cleared at birth. Two children bear mild hypothyroidism. During the same period six patients aged 0-17 years were treated for mediastinal teratoma. Only one was prenatally diagnosed and only two had some dyspnea. Removal was performed either by median sternotomy, thoracotomy, or thoracoscopy. They all survive and are free of disease. Teratomas of the neck may cause fetal disease and unmanageable neonatal airway obstruction. Prenatal diagnosis and planned multidisciplinary management are mandatory at birth. In contrast, only some mediastinal tumors cause respiratory embarrassment. Although benign, these tumors are sometimes immature and may metastasize to regional lymph nodes. Total surgical removal is curative. Thyroid insufficiency may be present at birth in cervical teratomas and may be aggravated by surgery.

Squamous cell carcinoma arising in a pediatric intra- and paravertebral teratoma

A 7-year-old boy presented with a 1-year history of back pain radiating to his left scapula and arm, with tenderness to palpation over the area. Laboratory studies were unremarkable. Computed tomographic scan showed a mixed lytic and sclerotic process at the T5-T6 level of the vertebral column in continuity with an adjacent paravertebral soft tissue mass. Nuclear medicine scan demonstrated increased uptake in the T5 vertebral body. Histology revealed invasive squamous cell carcinoma infiltrating mature, gliotic neural tissue, with areas of necrosis and prominent perivascular space involvement. Associated vertebral fragments showed bone destruction, reactive bone formation, and fibrosis. By immunohistochemistry, the carcinoma cells were positive for cytokeratin AE1/AE3, cytokeratin 5/6, EMA, and MIC-2 (membranous staining). The mature neural tissue was positive for GFAP; immature neural elements were not identified. Based on morphologic, immunohistochemical, and clinical features, this lesion was diagnosed as invasive squamous cell carcinoma arising within an intravertebral and paravertebral teratoma.

Extreme levels of alpha-fetoprotein in a newborn with a benign intrapericardial teratoma

We report a neonate presenting with an intrapericardial benign teratoma and an exceptionally high level of alpha-fetoprotein. Such severe elevation of alpha-fetoprotein in a neonate with a teratoma is usually associated with the presence of immature or malignant elements, compromising the prognosis. The tumour in our patient, however, proved to be completely benign. We discuss recent findings with regard to normal levels of alpha-fetoprotein levels in preterm infants, and in children with neonatal teratomas.

Intraplacental choriocarcinoma: experience from a tertiary referral center and relationship with infantile choriocarcinoma

The development of persistent gestational trophoblastic disease following an apparently uncomplicated term pregnancy is well-recognized; however, reports of confirmed intraplacental choriocarcinoma are rare. We report four cases of histologically reviewed intraplacental choriocarcinoma occurring in third-trimester pregnancies from the files of a regional trophoblastic disease unit. In all cases, macroscopic examination of the placenta appeared unremarkable, with small nondescript lesions being identified, thought to be fresh infarcts or intervillus thrombi. Histological examination demonstrated the presence of focal intraplacental choriocarcinoma. Review of the literature demonstrates primary intraplacental choriocarcinoma rarely may be associated with obstetric complications such as intrauterine death or fetal distress. But in most cases, the disease is initially asymptomatic, the diagnosis only being made following histopathological placental examination for other indications. Intraplacental choriocarcinoma may therefore manifest as a spectrum of clinical disease ranging from an incidental lesion diagnosed on placental pathological examination with no adverse effects on mother or baby, through to metastatic maternal disease that is present in about half of the cases, to disseminated fatal infantile choriocarcinoma.

Identification of recurrent chromosomal aberrations in germ cell tumors of neonates and infants using genomewide array-based comparative genomic hybridization

Human germ cell tumors (GCTs) of neonates and infants comprise a heterogeneous group of neoplasms, including teratomas and yolk sac tumors with distinct clinical and epidemiologic features. As yet, little is known about the cytogenetic constitution of these tumors. We applied the recently developed genomewide array-based comparative genomic hybridization (array CGH) technology to 24 GCTs derived from patients under the age of 5 years. In addition, we included seven tumors derived from children and adolescents older than 5 years. In the series from those under the age of 5 years, most teratomas displayed normal profiles, except for some minor recurrent aberrations. In contrast, the yolk sac tumors displayed recurrent losses of 1p35-pter and gains of 3p21-pter and of 20q13. In the GCTs of patients older than 5 years, the main recurrent anomalies included gains of 12p and of whole chromosomes 7 and 8. In addition, gains of the 1q32-qter region and losses of the 6q24-qter and 18q21-qter regions were frequent in GCTs of varied histology, independent of age. We concluded that array CGH is a highly suitable method for identifying recurrent chromosomal anomalies in GCTs of neonates and infants. The recurrent anomalies observed point to chromosomal regions that may harbor novel diagnostic/prognostic identifiers and genes relevant to the development of these neoplasms.

Establishment of oocyte population in the fetal ovary: primordial germ cell proliferation and oocyte programmed cell death

Strict control of cell proliferation and cell loss is essential for the coordinated functions of different cell populations in complex multicellular organisms. Oogenesis is characterized by a first phase occurring during embryo-fetal life and in common with spermatogenesis, during which mitotic proliferation of the germline stem cells, the primordial germ cells (PGC), prevails over germ cell death. The result is the formation of a relatively high number of germ cells depending on the species, ready to enter sex specific differentiation. In the female, PGC enter into meiosis and become oocytes, thereby ending their stem cell potential. After entering into meiosis in the fetal ovary, oocytes pass through leptotene, zygotene and pachytene stages before arresting in the last stage of meiotic prophase I, the diplotene or dictyate stage at about the time of birth. The most part of oocytes die during the fetal period or shortly after birth. It is widely accepted that in mammals a female is born with a fixed number of oocytes within the ovaries, which over the years progressively decreases without possibility for renewal. Once the oocyte reserve has been exhausted, ovarian senescence, driving what is referred to as the menopause in women, rapidly ensues. The fertile lifespan of a female depends by the size of the oocyte pool at birth and the rapidity of the oocyte pool depletion. Which mechanisms control PGC proliferation? Why do most of the oocytes die during fetal life and what are the mechanisms of such massive degeneration? Is it possible to prolong the lifespan of a female by reducing oocyte lost during the fetal life? This review reports some of the most recent results obtained in an attempt to answer these questions.