Schwannoma with rhabdomyoblastic differentiation: a unique variant of malignant triton tumor

A 54-year-old woman presented with intractable perianal, bilateral buttock, and radiating thigh/calf pain. An MRI scan showed an intradural, contrast-enhancing, ovoid mass in the cauda equina region at L1-L2. At laminectomy, the ovoid mass arose from a nerve root and, intact, was gross totally resected. Histologically, the dominant pattern was that of schwannoma. One year thereafter, the symptoms recurred. An MRI scan demonstrated an irregular, heterogeneously enhancing tumor recurrence. A repeat laminectomy disclosed a large fleshy tumor involving multiple nerve roots. The lesion was subtotally resected and showed pluridirectional differentiation toward embryonal rhabdomyosarcoma, primitive neuroectodermal tumor, and rare malignant epithelial cells. Review of the original tumor disclosed only foci of embryonal rhabdomyosarcoma and primitive neuroectodermal tumor. Based upon available data regarding divergent differentiation in peripheral nerve sheath tumors, this is a unique, previously undescribed tumor demonstrating rhabdomyosarcomatous, primitive neuroectodermal tumor and scant epithelial differentiation in a schwannoma. In essence, it is a variant of malignant Triton tumor because of its origin in a tumor consisting of well-differentiated Schwann cells. It supports the contention that the Schwann cell is the source of a variety of heterologous elements in nerve sheath tumors.     

The tanycytic ependymoma of the lateral ventricle: case report.

The tanycytic ependymoma is an extremely rare, primitive neuroectodermal tumor, arising from the ependymoglial cells or tanycytes. Such cells are generally seen in the primitive nervous system instead of the mature ependymal cells. The tanycytic ependymoma described in this report was found in a 42-year-old man. Histological analysis strongly suggested that this tumor originated from a primitive progenitor cell, the ependymoglia or the tanycyte in the lateral ventricle.     

Wilms' tumor metastatic to bilateral testes at presentation: case and review of the literature

A 7-year-old male with bilateral palpable testicular masses was found to have metastatic stage IV Wilms' tumors associated with both left renal and lung lesions. The patient was treated successfully with testicular-sparing bilateral partial orchiectomies, radical nephrectomy, chemotherapy, and radiation, with 8 years free of recurrence. This is the only reported case of bilateral testicular tumors from metastatic Wilms' tumor that were present at the initial presentation. A review of the literature of all previous reported cases of metachronous or related testicular metastatic Wilms' tumors is reported.     

Unbalanced translocation of chromosome 3p in Wilms' tumor.

Genetic studies in Wilms' tumor have most commonly shown a deletion involving band 13 on the p arm of chromosome 11 in association with aniridia. Structural rearrangements of chromosome 3p have been found in carcinoma of renal cell and lung origin but have not been previously reported in Wilms' tumors. We present two phenotypically normal, unrelated patients with Wilms' tumors, one of which was bilateral, in which cytogenetic analysis of the tumors showed an unbalanced translocation of the p arm of chromosome 3. Two biopsies were done in the patient with bilateral Wilms' tumor. The first biopsy specimen showed a translocation between chromosome 3 and 13 with partial trisomy of 3p and loss of material from 13q. The second biopsy three and a half months later again showed trisomy of chromosome 3p. The unilateral Wilms' tumor showed trisomy of 3p with partial loss of 7p. Neither patient showed a constitutional chromosomal abnormality and neither tumor showed any cytogenetic abnormality involving chromosome 11p. Quantitative DNA analysis was performed in the tumors of both patients. The bilateral Wilms' tumor was nearly diploid with a DNA index of 1.284 (mean ploidy, 2.45; SD, 0.854) while the unilateral Wilms' tumor was aneuploid with a DNA index of 1.531 (mean ploidy, 3.35; SD, 0.976). DNA analysis results are discussed in relationship to the chromosome abnormality seen on the karyotype analysis. These cytogenetic findings suggest that genetic oncogenesis in Wilms' tumor is heterogenous.     

Primary extrarenal Wilms' tumor in children

We report three additional cases of primary extrarenal Wilms' tumor and review those cases previously documented. Analysis of the location, histopathology, treatment, and survival of these cases supports the following conclusions: Wilms' tumor may occur in an extrarenal location without primary renal involvement and must be included in the differential diagnosis of abdominal, pelvic, and inguinal masses; an extrarenal location supports a more frequent occurrence of ectopic metanephric blastema than was previously recognized or origin of Wilms' tumor from a more primitive mesodermal tissue; and the natural history and prognosis of extrarenal and renal Wilms' tumors appears similar.     

A primitive neuroectodermal tumor on the face: case report

In 1918, Stout defined the lesion in which small round cells originating from the ulnar nerve formed a rosette as neuroepithelioma. It was claimed that this tumor originated from neuroectodermis and was different from the classical neuroblastoma. The term primitive neuroectodermal tumor (PNET) involves a group of tumors of the soft tissue originating from neural crest and resulting from the brain, spinal cord and branches of the sympathetic nervous system. Extracranial primitive neuroectodermal tumors originate from neural crest cells outside the sympathetic and central nervous system. PNET also has some distinctive histological, immunohistochemical and ultrastructural features. It is usually encountered in children and young adults; most frequently located in thoracopulmonary region (Askin's tumor). The second most commonly involved body part is the extremities. It is very rarely located on the face. PNET is an aggressive tumor. In fact, the disease has a rapid progression, causes local or distant metastases and 50% of the patients die within two years of the presentation. It is treated with aggressive surgery as well as chemotherapy and radiotherapy. In this report, we presented a case of PNET located on the right cheek with multiple distant metastases. Clinicians should be on alert when treating facial tumors, not to skip PNET, which is a very aggressive one.     

Primitive neuroectodermal tumors

The primitive neuroectodermal tumors (PNETs) of Hart and Earle constitute an important fraction of pediatric brain tumors that are clinically characterized by their aggressive behavior. In 1983, Rorke expanded the term “PNET” to include all small cell embryonal neoplasms of neuroectodermal origin, regardless of the location of the tumor. More recently, Dehner also proposed the terms “central” and “peripheral” PNETs, and the provocative concept of “PNET” has now come to encompass a diverse group of tumors in both the central and peripheral nervous systems. The acronym “PNET” has thus become a confusing and controversial term in the diagnosis and classification of pediatric embryonal tumors. We reviewed ten papers concerning the various aspects of PNETs.     

Primitive neuroectodermal tumor in a 57-year-old man

Primitive neuroectodermal tumors are rare cerebral neoplasms previously described only in children and young adults. This report describes such a tumor arising in the left frontal lobe of a 57-year-old man. After surgical resection and radiation therapy to the primary site, the patient developed extensive central nervous system metastases that led to his death. The histopathologic, radiographic, and clinical features of this case suggest that future therapeutic protocols for primitive neuroectodermal tumor should be similar to those for childhood medulloblastoma or neuroblastoma.     

Recurrent solitary fibrous tumor of the falx cerebri with intraventricular extension: case report

A 61-year-old male presented with a recurrent solitary fibrous tumor (SFT) arising from the falx cerebri with intraventricular extension manifesting as nausea and vomiting. Magnetic resonance imaging showed the heterogeneously enhanced tumor in the falx, which extended to the bilateral lateral ventricles and the third ventricle. Total tumor removal was performed via the bifrontal interhemispheric approach. Histological examination showed mostly spindle cells with rich intercellular fibers. Immunohistochemical examination showed strong staining for CD34 in the cytoplasm but no staining for epithelial membrane antigen. Reexamination of the two previous tumor specimens, previously identified as fibrous meningioma, found SFT. The differential diagnosis of SFT in the central nervous system from fibrous meningioma and hemangiopericytoma requires immunohistochemistry and electron microscopy.     

Primary intradural extraosseous Ewing sarcoma of the spine: case report and literature review

BACKGROUND AND IMPORTANCE: To report a rare case of spinal intradural extraosseous Ewing sarcoma in an adult and review current literature. Although Ewing sarcoma belongs to the family, the treatment modalities are different, and thus the correct diagnosis is very important despite its rare occurrence. CLINICAL PRESENTATION: A 56-year-old woman presented with nocturnal bilateral buttock and leg pain. Magnetic resonance imaging (MRI) showed an enhancing intradural extramedullary extraosseous tumor at L1. INTERVENTION: A T12-L2 laminectomy was performed to resect the tumor. Immunohistochemical analysis confirmed the diagnosis of Ewing sarcoma. A thorough diagnostic workup did not reveal any bony origin of the tumor. Primary intradural central nervous system Ewing sarcoma is infrequently encountered and shares imaging and histopathological features with central primitive neuroectodermal tumors. Establishment of the right diagnosis is crucial because it mandates a distinct workup and treatment modality different from that for central primitive neuroectodermal tumor. Although osseous Ewing sarcoma predominantly occurs in children and young adults, extraosseous central nervous system Ewing sarcoma is not uncommon in adults and should therefore be considered in the differential diagnosis of extraosseous small blue cell tumors in adult patients.     

Enhancement of growth of primary metastatic fresh human tumors of the nervous system by epidermal growth factor in serum-free short term culture

Using the adhesive tumor cell culture system, we studied the effect of epidermal growth factor (EGF) on 16 primary and 7 metastatic fresh human tumors of the nervous system cultured in serum-free and serum-supplemented media at low cell density. In serum-free conditions, EGF significantly enhanced the growth of glial tumor cells. This positive effect was less pronounced for metastases to the brain. No significant enhancement was observed for the other tumor types (primitive neuroectodermal tumors and various tumors of neuroepithelial/mesenchymal origin). The addition of serum obscured this effect of EGF, even at the lowest cell densities. In 7 tumors, the simultaneous addition of platelet-derived growth factor did not enhance the EGF response. Subtypes of brain tumors respond to EGF in vitro under serum-free conditions.     

Renal primitive neuroectodermal tumor in childhood with intracardiac extension

Primary primitive neuroectodermal tumors of the kidney are exceptionally rare and usually affect children and young adults. We report the first pediatric case of renal primitive neuroectodermal tumor presenting with tumor extension along the inferior vena cava to the right ventricle. This case highlights that when considering a renal tumor with significant intravascular extension in the pediatric age group, although the most likely diagnosis remains Wilms tumor, other rare entities may also demonstrate similar clinical and imaging features.     

Embryonal central neuroepithelial tumors and their differentiating potential. A cytogenetic view of a complex neuro-oncological problem

The embryonal central nervous system (CNS) neoplasms are reviewed with special reference to their differentiating potential and in the light of current neuro-oncogenetic concepts partly derived from the experimental induction of neural tumors. The conceptual (and, occasionally, practical) distinction between adult-type and embryonal CNS tumors raises a complex problem, because neoplastic transformation essentially involves replicating stem cells in tissues of renewal and because in the human brain such cells are found mostly in the course of CNS development. A cytogenetic scheme is therefore needed to serve as a frame of reference for a classification of embryonal CNS tumors that will account for the different histological entities documented so far and for the range and the restrictions of their differentiating capabilities. Most embryonal CNS tumors can be fitted into such a scheme. The cerebral medulloepithelioma, the cerebral and cerebellar neuroblastomas, the primitive polar spongioblastoma, and the ependymoblastoma show characteristic morphological features and a correspondingly distinctive cellular differentiating potential. The differentiating capabilities of the cerebellar medulloblastoma, the pineoblastoma, and the retinoblastoma are also distinctive, and are apparently determined by the cytogenesis of the area of the CNS in which the tumors originate. The indiscriminate application of a simplistic concept that would include all the so-called "primitive neuroectodermal tumors" into a single neuroepithelial tumor entity is unlikely to bring further understanding to the problem.     

Successful treatment of a case of advanced adult Wilms' tumor with pre-surgical chemotherapy, irradiation and radical nephrectomy

A 37-year-old male was referred with a huge renal mass and multiple lung lesions. Abdominal and chest computed tomographic scan revealed a 11×15×17. 5 cm right renal tumor and multiple lung metastases. Neither tumor was enhanced, and no lymph adenopathy was detected. Percutaneous needle core biopsy was performed and the tumors were diagnosed as Wilms' tumor histologically supported by immunohistological positive staining to WT-1 and CD56. Since lung metastases were detected and the renal tumor reached the abdominal aorta on the left side, presurgical systemic chemotherapy (ifosphamide＋ carboplatin＋etoposide ; ICEx 4 courses) was performed. The renal tumor and the lung metastases were markedly decreased in size and subjected to a radical nephrectomy. Histological examination confirmed the diagnosis of Wilms' tumor without anaplastic change categorized as mesenchymal type. As an adjuvant therapy, irradiation to renal bed (40 Gy/20 fr) and bilateral lung (12 Gy/8 fr) were performed. Six months after the end of the therapy, no evidence of recurrence was detected.     

Primary spinal primitive neuroectodermal tumor: A single center series with literature review

Context: Primary spinal primitive neuroectodermal tumor (PNET) of the central nervous system has a low incidence. The intraspinal case is very rare. Around 30 cases have been reported so far. We summarized the cases of primary spinal PNET available in the database of our institute, either intramedullary or extramedullary cases. Then we did literature review of the same disease.Findings: There were eight cases of primary spinal PNET available in our database, with one intramedullary case and seven extramedullary cases. Surgical resection was performed. The histology diagnosis was PNET. Peri-operative image examinations of the whole central nervous system (CNS) were performed to exclude tumors other than spinal cord origin. Then during literature review, 33 reports of the disease were included. The pre-operative diagnosis rate was low. The disease had a high recurrence rate and poor prognosis given available treatment.Conclusion: Primary spinal primitive neuroectodermal tumor is of high malignancy. Little is known due to its quite low incidence. The prognosis is poor due to lacking of effective treatment strategy. Present treatment strategy is referred to other common CNS malignancies like glioma. Further investigation of the disease is necessary.     

Primitive neuroectodermal tumor arising in the ulnar nerve. A case report

Malignant peripheral nerve tumors are rare. A neuroectodermal tumor arose in a 59-year-old man from the ulnar nerve. Typically, the tumor reproduces some of the appearances of cells of the primitive central nervous system. The possibility that a primary tumor of the sympathetic nervous system, especially of the adrenal glands, should be considered in the differential diagnosis. The tumor may arise from a major peripheral nerve and show features of growth patterns of the embryonic central nervous system. Blood stream spread is not uncommon; awareness of this proclivity makes early diagnosis mandatory.     

Hemangiopericytoma in the trigone of the lateral ventricle

A 67-year-old right-handed woman presented with a case of hemangiopericytoma in the lateral ventricle manifesting as digit number memory disturbance, sensory aphasia, and right quadrantanopsia. Magnetic resonance imaging demonstrated a 6-cm homogeneously enhanced mass in the trigone of the left lateral ventricle. The tumor was totally removed via the left inferior temporal gyrus. The histological findings were consistent with hemangiopericytoma. Differential diagnosis of hemangiopericytoma from meningioma and solitary fibrous tumors is very important because the clinical behavior of hemangiopericytoma is very aggressive, including local recurrence or distant metastases in the central nervous system and periphery. Histological confirmation is required to make a definitive diagnosis. The present patient did not receive radiation therapy, but developed no local recurrence or metastases. Complete surgical resection and awareness of hemangiopericytoma in the lateral ventricle are very important for good clinical outcome.     

Bilateral multifocal Wilms' tumor

A three-year-old boy who presented with symptoms of peritonitis was found to have four Wilms' tumors affecting both kidneys. Individual enucleation of three tumors in the right kidney plus left lower nephrectomy were performed. Chemotherapy was administered for one year. The diagnosis of Wilms' tumor was confirmed on each specimen by the histologic studies. The child remains asymptomatic and developing normally six years after the initial surgical treatment. Bilateral partial nephrectomies is the most conservative of the surgical treatments available for bilateral Wilms' tumor.     

Teratoid Wilms' tumor: case report of a rare variant that can mimic aggressive biology during chemotherapy

Teratoid Wilms' tumor is considered by some as a variant of Wilms' tumor containing at least 50% heterologous differentiated tissue. Fewer than 30 cases have been described. We report a 9-month-old boy with bilateral Wilms' tumors who did not respond to multiagent chemotherapy and underwent right nephrectomy that showed a teratoid Wilms' tumor. The patient continued to survive despite cessation of treatment. The overall predominance of differentiated stromal elements in this subtype of Wilms' tumor might explain the poor response to chemotherapy yet generally favorable outcome. Recognition of this subtype on biopsy might justify earlier surgical intervention that, for bilateral tumors, might allow for greater nephron sparing.