Primary retroperitoneal seminoma - embryology, histopathology and treatment particularities.

INTRODUCTION: Retroperitoneal seminoma is a very rare form of cancer, with embryological origin represented by primordial germ cells from the urogenital ridges left behind during the fetal development. Extragenital germ cell tumors can also occur in the mediastinum or the pineal gland. The aim of this paper is to outline the particularities and draw embryological, histopatological and treatment conclusions regarding extragonadal germ cell tumors. PATIENT AND METHODS: A 43-year-old patient without any additional pathology was admitted for anemia of unknown etiology. The clinical examination revealed through deep abdominal palpation a mass in the left flank, and normal testes. Thoraco-abdomino-pelvic computed tomography (CT) scan showed a large retroperitoneal tumor adjacent to the great vessels in the left lumbo-iliac region. The blood work revealed just a low hemoglobin and hematocrit. With the established diagnosis of retroperitoneal tumor, radical surgical removal was decided. During the surgery, we were required to dissect a large solid encapsulated tumor mass from the aorta and the common iliac artery, starting at the renal pedicle all the way to the left iliac bifurcation. The surgical access was obtained through a transperitoneal left subcostal incision prolonged pararectally. Histopathological and immunohistochemical studies revealed a seminoma of the usual type. After the histological findings, the patient's tumor markers were investigated (LDH - lactate dehydrogenase, ßHCG - beta-human chorionic gonadotropin, αFP - alpha-fetoprotein), all values being within normal ranges. In addition, the left testicle was thoroughly reexamined, clinically, through ultrasound and magnetic resonance imaging (MRI) scans, and no abnormalities were observed. After the surgery, the patient followed three courses of chemotherapy (BEP - Bleomycin, Etoposide and Cisplatin). RESULTS: The CT scan done 24 months after surgery found no signs of local or distant tumor recurrence. The patient entered a follow-up schedule consisting of periodical clinical, serological and imagistic evaluations. CONCLUSIONS: Primary retroperitoneal seminoma is a rare entity that must be taken into account when treating a retroperitoneal tumor. It develops out of the urogenital ridge, while the testes are normal. Thorough testicular evaluation (clinical, ultrasound and serum markers) is mandatory in all retroperitoneal tumors. The histopathological analysis is crucial for an accurate diagnosis and a proper management strategy. Through radical surgery and chemotherapy, the patients that are diagnosed prior to massive visceral metastatic dissemination can be cured.

Neuroblastoma in monozygotic twins with distinct presentation pathology and outcome: is it familial or in utero metastasis.

To date ten sets of monozygotic twins with neuroblastoma have been reported in the literature. Twin-to-twin in utero metastasis have been proposed as the mechanism of tumor development in the second twin; based on similar pathology, presence of metastatic disease, absence of a primary tumor, and/or later presentation in the second twin. Hereditary neuroblastoma has not been described in this context. We propose that primary neuroblastoma can occur in monozygotic twins without twin-twin transmission; due to the different ages of presentation, histology, ploidy, and tumor behavior.

[Prenatal diagnosis of retroperitoneal neuroblastoma. Case report]. / Diagnóstico prenatal de neuroblastoma retroperitoneal. Reporte de un caso.

Neuroblastoma is the foremost malignant neoplasm of the fetus and neonate. It is a tumor of the sympathetic nervous system that originates from the neural crest which etiology is largely unknown. Due to its general variability in outcome, neuroblastoma has long been considered one of the most enigmatic of cancers. Although technological advances in ultrasonography have possible intrauterine detection, prenatal diagnosis is still a rare event. This kind of tumor has a high morbidity and mortality rate due to the metastatic risk. Early detection of the tumor is critical to improve outcome. We report a case of retroperitoneal neuroblastoma diagnosed at 32 week of gestation.

Origin and mechanisms of formation of fetus-in-fetu: two cases with genotype and methylation analyses.

Fetus-in-fetu (FIF) is a condition in which a host infant has a fetus-like mass(es) within its body. We describe here results of molecular genetic analysis in two cases of FIF. In FIF-1, a male host had two retroperitoneal fetiform masses each with a vertebral column, and in FIF-2, a fetiform mass with vertebral column was present in the cranial cavity of a male host. Genotyping of each case using microsatellite markers showed that the host infant and its fetus(es) inherited one copy each of parental alleles and shared identical genotypes. These findings were confirmed by single nucleotide polymorphism (SNP) analysis using Affymetrix GeneChip Human Mapping 50K Array, and supported a monozygotic twin theory of FIF. Analysis of the methylation status was done in both cases at the differentially methylated region (DMR) within the human IGF2-H19 locus after bisulfite treatment, methylation-specific PCR, and cloning of PCR products. Normally, only the paternal allele is methylated and the maternal allele unmethylated in DMR. However, in FIF-1, 7 (46.7%) of 15 clones from a fetiform mass and 6 (66.7%) of 9 clones from the other mass showed an unmethylated paternal allele, while the methylation status of a host infant and its fetiform mass in FIF-2 was the same in all clones examined with normal patterns. These data suggest that in FIF-1, two isolated blastocysts originated from one zygote, one of the two was implanted into (or included by) the other blastocyst during the process of methylation, and such abnormal implantation may have occurred in FIF-2 after the establishment of methylation. This is the first case of FIF showing different methylation patterns between a host infant and fetiform mass.

Prenatal diagnosis, pathology, and genetic study of fetus in fetu.

We report the prenatal diagnosis, pathology, cytogenetics, and molecular studies of a retroperitoneal fetus in fetu. Prenatal ultrasonography of the host fetus in the third trimester showed an anencephalic, acardiac mass with identifiable extremities and spine within an intra-abdominal cystic mass. Pathological examination revealed a fetiform mass weighing 20 g with four extremities, digits, vertebral bodies, an oral cavity with developing teeth, primitive male external genitalia, a urinary bladder, a cloaca with an external opening, large intestines, a membranous capsule, and an umbilical cord with one artery, one vein, and Wharton's jelly. Histological examination demonstrated nerve bundles in the fibrocollagenous tissue below the cuboidal surface epithelium of the membranous capsule, and absence of lamina elastica interna and vasa vasorum in the single artery of the umbilical cord. Both the host infant and the fetus in fetu had a normal 46,XY karyotype. Molecular analysis using informative genetic markers showed no genetic difference between the host infant and the fetiform mass. We report this case as an unusual example of fetus in fetu in co-existence with an amnion-like membrane containing nerve bundles and with a well-formed umbilical cord. We demonstrate that fetus in fetu can be diagnosed prenatally if the fetiform mass has well-developed limbs and spine. We emphasize the necessity for suspicion of fetus in fetu when a well-defined encapsulated cystic mass with calcified solid components is detected prenatally in a fetus by ultrasonography.

Retroperitoneal cystic neuroendocrine tumor. A case report.

A 21 cm retroperitoneal cystic mass was excised from a 71 year old woman. The cyst was filled with a hemorrhagic fluid and contained a 5 cm parietal hemorrhagic nodule. On histology, the nodule was composed of a uniform population of round cells arranged in trabeculae and nests. The neoplastic cells were immunoreactive to cytokeratin, EMA, NSE, chromogranin A, pancreatic polypeptide (PP) and Gastrin (G). Ultrastructural observation of neurosecretory granules confirmed the neuroendocrine nature of the tumor. No other lesions were detected and a diagnosis of primary epithelial neuroendocrine tumor was rendered. The histogenesis of the tumor including the possibility of a paraganglionic origin is discussed.

The association of congenital neuroblastoma and congenital heart disease. Is there a common embryologic basis?

Several authors have reported an association between neuroblastoma and congenital heart disease; others contend that, unlike specific well-known associations between malignancy and congenital defects (Wilm's tumor and aniridia, leukemia and Down's syndrome), no real relationship exists. We present three cases of cyanotic congenital heart disease in which subclinical neuroblastoma was found. We speculate that abnormal neural crest cell migration and development may be a common link between cardiac malformations and congenital neuroblastoma.

Primary retroperitoneal mucinous cystadenocarcinoma.

A case of primary retroperitoneal cystadenocarcinoma is presented as the fourth reported case in the world literature to date. The cyst was removed intact and demonstrated an infiltrating malignant process with nuclear pleomorphism and mitotic activity. No ovarian tissue was identified and a cancer antigen 125 (CA 125) test was normal. The patient underwent a staging procedure subsequently that included peritoneal washings, hysterectomy, bilateral salpingoophorectomy, and iliac node dissection. No metastases were found and the patient is without recurrence 22 months postoperative. The literature is reviewed to better define the origin and prognosis of these tumors.

Retroperitoneal embryonal carcinoma/yolk sac tumor. A case report and a review of the histogenesis.

A case of 26-year old man, with a large primary retroperitoneal tumor which showed the pattern of embryonal carcinoma as well as yolk sac tumor, is reported. The disease ran an aggressive course and led to death within 8 months from the onset of clinical symptoms. Characteristic histological and ultrastructural patterns with Schiller-Duval bodies and adenocarcinomatous differentiation were accompanied by diffuse expression of alpha-fetoprotein and human chorionic gonadotropin expression in isolated cells, as well. The histogenesis of the tumor may be interpreted in terms of the reflection of the very early stages of the embryonal development rather than by the totipotent-neoplastic-germ-cell approach.

Retroperitoneal urogenital ridge transitional cell carcinoma.

A rare case of retroperitoneal transitional cell carcinoma arising from primitive urogenital remnants is described in a 50-year-old female. The patient had a 15 X 12 cm firm to cystic mass in the left iliac fossa which was markedly adherent to retroperitoneal structures and which could not be excised. Biopsy from the mass revealed transitional cell papillary carcinoma. Intravenous pyelogram and cystoscopy were normal. Cystogram done postoperatively did not show any communication with any adult organ. Radiotherapy resulted in only partial regression, and the patient died about 2 years later.

Developmentally heterotopic urogenital tissues in a retroperitoneal lipoma with hematopoiesis.

This report concerns an unusual retroperitoneal lipoma with hematopoiesis in a 49-year-old male. A unique feature is the presence of well differentiated male urogenital tissues, such as the prostatic gland, urethra and urinary bladder in part of the tumor. The process of the differentiation of these tissues is also illustrated. Although this lipoma attained a large size weighing 1,500 g, it is apparently a kind of malformation derived from the sequestered retroperitoneal Wolffian vestige. No similar cases have so far been reported in the world literature.