Immunophenotypic Characterization of Germ Cell Tumor-Derived Primitive Neuroectodermal Tumors: Evidence for Frequent Neuronal and/or Glial Differentiation.

CONTEXT.­: Primitive neuroectodermal tumors (PNETs) may arise as a somatic-type malignancy in germ cell tumors. In this setting, most PNETs resemble those of the central nervous system and lack chromosome 22 translocations. However, description of the morphologic and differentiation spectrum of PNETs arising from germ cell tumors is lacking. OBJECTIVE.­: To investigate the morphologic and immunohistochemical features of these tumors, concentrating on neuronal and glial features. DESIGN.­: We selected cases based on a morphologically identifiable glial and/or differentiated neuronal component in association with the undifferentiated PNET. Immunohistochemistry for glial fibrillary acidic protein, S100 protein, synaptophysin, chromogranin A, and SOX11 was performed on tumors with available material, with the scoring of both staining intensity (0-3) and extent (0-3). Thirteen qualifying PNETs of testicular origin with available immunohistochemical stains or stainable material were identified. The complete stain panel was performed in 10 tumors. RESULTS.­: SOX11 demonstrated positive staining in the undifferentiated PNET component of all tumors (10 of 10) and was rarely positive in the differentiated (ie, neuronal/glial) component (1 of 10; focal and weak); synaptophysin was slightly less sensitive in the undifferentiated component (12 of 13; often focal and weak) and also showed positivity in the neuronal/glial component (5 of 13). Glial fibrillary acidic protein and S100 were more frequently positive in the differentiated areas (83% and 77%, respectively) compared with undifferentiated areas (25% and 17%, respectively). CONCLUSIONS.­: SOX11 is a sensitive immunohistochemical marker for testicular PNET, particularly those lacking differentiation. Testicular PNETs often demonstrate glial and/or neuronal differentiation. Differentiation is marked by the acquisition of S100 and glial fibrillary acidic protein expression and SOX11 loss.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the ileum: case report of a 16-year-old Chinese female and literature review.

BACKGROUND: Ewing's sarcoma (ES) and primitive neuroectodermal tumors (PNET) are closely related tumors. Although soft tissue ES/PNET are common in clinical practice, they are rare in the small intestine. Because of the absence of characteristic clinical symptoms, they are easily misdiagnosed as other benign or malignant diseases. CASE PRESENTATION: Here, we present the case of a 16-year-old female who complained of anemia and interval hematochezia. Her serum test results showed only a slight elevation of CA-125 and a low level of hemoglobin. Computer tomography and magnetic resonance imaging revealed a cystic and solid mass in the lower abdominal quadrant and pelvic region, which prompted suspicion of a malignant gastrointestinal stromal tumor of the small intestine. After resection, the tumor's histology and immunohistochemistry (positive for CD99, vimentin and synaptophysin) results suggested ES/PNET. Fluorescent in situ hybridization tests proved the breakpoint rearrangement of the EWSR1 gene in chr 22.Ultrastructural analysis revealed neurosecretory and glycogen granules in the tumor cell cytoplasm. CONCLUSIONS: Together, these data supported the diagnosis of a rare case of localized ES/PNET in the small intestine without adjuvant chemo- or radiotherapy. To our knowledge, this is the first report from China of a primary small bowel ES/PNET in the English-language literature. In addition, on the basis of findings from previous publications and the current case, the optimal treatment for localized gastrointestinal ES/PNET is discussed.

Diagnostic utility of cyclin D1 in the diagnosis of small round blue cell tumors in children and adolescents.

Small round blue cell tumors (SRBCTs) of children and adolescents are often diagnostically challenging lesions. With the increasing diagnostic approach based on small biopsies, there is the need of specific immunomarkers that can help in the differential diagnosis among the different tumor histotypes to assure the patient a correct diagnosis for proper treatment. Based on our recent studies showing cyclin D1 overexpression in both Ewing sarcoma/primitive peripheral neuroectodermal tumor (EWS/pPNET) and peripheral neuroblastic tumors (neuroblastoma and ganglioneuroblastoma), we immunohistochemically assessed cyclin D1 immunoreactivity in 128 cases of SRBCTs in children and adolescents to establish its potential utility in the differential diagnosis. All cases of EWS/pPNET and the undifferentiated/poorly differentiated neuroblastomatous component of all peripheral neuroblastic tumors exhibited strong and diffuse nuclear staining (>50% of neoplastic cells) for cyclin D1. In contrast, this marker was absent from rhabdomyosarcoma (regardless of subtype) and lymphoblastic lymphoma (either B- or T-cell precursors), whereas it was only focally detected (<5% of neoplastic cells) in some cases of Wilms tumor (blastemal component) and desmoplastic small round cell tumor. Our findings suggest that cyclin D1 can be exploitable as a diagnostic adjunct to conventional markers in confirming the diagnosis of EWS/pPNET or neuroblastoma/ganglioneuroblastoma. Its use in routine practice may also be helpful for those cases of SRBCT with undifferentiated morphology that are difficult to diagnose after application of the conventional markers.

Oncocytic variant of malignant gastrointestinal neuroectodermal tumor: a potential diagnostic pitfall.

Malignant gastrointestinal neuroectodermal tumor (MGNET) is a very rare, aggressive malignant neoplasm that may occur in any location in the gastrointestinal tract. Malignant gastrointestinal neuroectodermal tumors typically consist of sheet-like to pseudopapillary proliferation of primitive-appearing epithelioid cells with a moderate amount of lightly eosinophilic cytoplasm, round nuclei and small nucleoli, often in association with osteoclast-like giant cells. By immunohistochemistry, these tumors show expression of S100 protein and SOX10, in the absence of expression of more specific melanocytic markers (eg, HMB45, Melan A). Genetically, malignant gastrointestinal neuroectodermal tumors are characterized by rearrangements of the EWSR1 or FUS genes with CREB1 or ATF1. We report a case of gastric malignant gastrointestinal neuroectodermal tumor occurring in a 46-year-old woman and showing striking oncocytic cytoplasmic change, a previously undescribed potential diagnostic pitfall. An initial needle biopsy showed large, eosinophilic cells with S100 protein and SOX10 expression and lacking expression of KIT, DOG1, Melan A, keratin, chromogranin, or smooth muscle actin, and was interpreted as representing a granular cell tumor. The subsequent excision specimen showed similar-appearing areas, but also contained small more primitive-appearing areas, lacking oncocytic change and having high nuclear grade and brisk mitotic activity. This resection specimen was initially diagnosed as a malignant granular cell tumor. However subsequent gene expression profiling studies showed an EWSR1-ATF1 fusion, confirmed with fluorescence in situ hybridization for EWSR1, and a final diagnosis of MGNET with oncocytic change was made. This case highlights a previously undescribed pitfall in the diagnosis of MGNET, oncocytic change, and suggests that MGNET should be included in the differential diagnosis for unusual oncocytic neoplasms of the gastrointestinal tract.

Heavy Metal Bioaccumulation in an Atypical Primitive Neuroectodermal Tumor of the Abdominal Wall.

Heavy metals are able to interfere with the function of vital cellular components. Besides in trace heavy metals, which are essential at low concentration for humans, there are heavy metals with a well-known toxic and oncogenic potential. In this study, for the first time in literature, we report the unique adulthood case of an atypical primitive neuroectodermal tumor of the abdominal wall, diagnosed by histology and immunohistochemistry, with the molecular hybridization support. The neoplasia occurred in a patient chronically exposed to a transdermal delivery of heavy metal salts (aluminum and bismuth), whose intracellular bioaccumulation has been revealed by elemental microanalysis.

Adamantinoma-like Ewing family tumors of the head and neck: a pitfall in the differential diagnosis of basaloid and myoepithelial carcinomas.

Ewing sarcoma family tumors (EFTs) of the head and neck are rare and may be difficult to diagnose, as they display significant histologic overlap with other more common undifferentiated small blue round cell malignancies. Occasionally, EFTs may exhibit overt epithelial differentiation in the form of diffuse cytokeratin immunoexpression or squamous pearls, resembling the so-called adamantinoma-like EFTs and being challenging to distinguish from bona fide carcinomas. Furthermore, the presence of EWSR1 gene rearrangement correlated with strong keratin expression may suggest a myoepithelial carcinoma. Herein, we analyze a series of 7 adamantinoma-like EFTs of the head and neck, most of them being initially misdiagnosed as carcinomas because of their anatomic location and strong cytokeratin immunoexpression, and subsequently reclassified as EFT by molecular techniques. The tumors arose in the sinonasal tract (n=2), parotid gland (n=2), thyroid gland (n=2), and orbit (n=1), in patients ranging in age from 7 to 56 years (mean, 31 y). Microscopically, they departed from the typical EFT morphology by growing as nests with peripheral nuclear palisading and prominent interlobular fibrosis, imparting a distinctly basaloid appearance. Moreover, 2 cases exhibited overt keratinization in the form of squamous pearls, and 1 sinonasal tumor demonstrated areas of intraepithelial growth. All cases were positive for CD99, pancytokeratin, and p40. A subset of cases showed synaptophysin, S100 protein, and/or p16 reactivity, further confounding the diagnosis. Fluorescence in situ hybridization assays showed EWSR1 and FLI1 rearrangements in all cases. Our results reinforce that a subset of head and neck EFTs may show strong cytokeratin expression or focal keratinization, and are therefore histologically indistinguishable from more common true epithelial neoplasms. Thus, CD99 should be included in the immunopanel of a round cell malignancy regardless of strong cytokeratin expression or anatomic location, and a strong and diffuse CD99 positivity should prompt molecular testing for the presence of EWSR1 gene rearrangements.

A Primary Primitive Neuroectodermal Tumor Arising from Left Subclavian Vein and Extending along Left Brachiocephalic Vein and Superior Vena Cava into Right Atrium.

Primitive neuroectodermal tumor (PNET) is an extremely rare malignancy thought to be derived from fetal neuroectodermal precursor cells. It usually occurs in central and peripheral nervous system or soft tissue and bone, while intravenous or intracavitary PNET is considered as an extremely rare tumor. We reported a case of a 44-year-old woman who presented with the left unilateral facial and neck swelling. Magnetic resonance imaging revealed a tape-shaped solid mass within left subclavian vein, left brachiocephalic vein, superior vena cava, and right atrium; the proximal end proportion occupied almost the entire right atrium with a pedicle flip protruded into the right ventricle. Ultrasonography revealed an irregular hypoechnoic mass arising from the left subclavian vein, which extended along the left brachiocephalic vein and superior vena cava into the right atrium and up to the right ventricle. Positron emission tomography-computed tomography revealed several hypermetabolic thyroid nodules with no evidence of intravenous hyperactive lesion. The patient underwent tumor resection under cardiopulmonary bypass. At 15 days postoperatively, total thyroidectomy and resection of the left subclavian vein were simultaneously performed. The patient received chemotherapy and radiotherapy later. Histologically, the neoplasm displayed small, round, blue cells with hyperchromatic nuclei and scant cytoplasm. The neoplastic cells showed a strong immunopositivity for CD99, synaptophysin, CD56, CD57, and friend leukemia integration 1, thus confirming a diagnosis of the PNET. Histopathological examination of the thyroid showed papillary carcinoma. Thus, this PNET had no definitive organ or tissue of origin, which primarily originated from the left subclavian vein with tumor extension along the superior vena cava to the right ventricle.

Extraosseous Ewing sarcoma and peripheral primitive neuroectodermal tumor of the thyroid gland: Case report and review.

The Ewing family of tumors and peripheral primitive neuroectodermal tumor (pPNET) represent different manifestations of the same entity. Immunohistochemical and cytogenetic studies suggest that these tumors have a common origin. Ewing sarcoma is more common in bone, while pPNET is more common in soft tissues. Extraosseous Ewing sarcoma (EoES) is rare. We present the case of a 48-year-old man who presented with acute obstructive respiratory failure secondary to a large thyroid swelling. The patient was initially diagnosed with giant B-cell non-Hodgkin lymphoma and treated with chemotherapy. However, subsequent immunohistochemical staining of biopsy specimens revealed that the patient actually had EoES/pPNET of the thyroid gland. We performed a nearly complete surgical resection of the tumor plus a total laryngectomy and resection of five tracheal rings. However, the patient died of a cerebral metastasis 1 month later after he had completed one cycle of postoperative chemotherapy.

Primary pulmonary primitive neuroectodermal tumor metastasis to the pancreas: a rare case with seven-year follow-up.

There are only nine primitive neuroectodermal tumor (PNET) cases that have arisen in lung parenchyma without pleural or chest wall involvement in the literature. Here, we present a long-term survival case of pulmonary PNET. A pulmonary mass was detected in a 19-year-old man on a chest radiograph and computed tomography image. At the three-year follow-up, the mass had enlarged in diameter by two-fold. The lesion was resected via lower left lobectomy. Histologically, the tumor was composed of uniform cells with round nuclei and scanty cytoplasm arranged in lobules with rosettes and pseudorosettes formation. Immunohistochemically, the tumor was positive for CD99, vimentin, neuron specific enolase and chromogranin A, and negative for cytokeratins, CD3, desmin, and leukocyte common antigen. Pancreatic metastasis occurred sixteen months after the first surgery, which was managed by pancreatectomy. The patient has survived seven years after the mass was initially detected, and four years after the first lobectomy. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1500847644913244.

Ewing sarcoma of the thoracic wall in a 54-year-old man.

Ewing tumor is the second most common bone tumor in children. Its variant, malignant small cell tumor of the thoracopulmonary region, is infrequent in children and extremely rare in adults. A multimodal treatment approach is preferred for this tumor. We describe a rare case of primitive neuroectodermal tumor/Ewing sarcoma arising from the thoracic wall in a 54-year-old man. He underwent extensive resection of the tumor followed by adjuvant chemotherapy and radiotherapy.

Primitive chest wall neuroectodermal tumor in a pediatric patient.

A 13-year-old boy with a primitive neuroectodermal tumor of the chest wall is presented. After four cycles of chemotherapy, a computed tomography scan of his chest showed a larger mass invading the left upper lobe of the lung. He underwent resection of the left chest wall from the left fourth to sixth ribs, including the tumor, combined with left upper lobectomy and lymph node dissection. A diagnosis of primitive neuroectodermal tumor was confirmed histopathologically and immunohistochemically. After surgery, four cycles of chemotherapy with ifosfamide and etoposide were given. One year after treatment, the patient is currently doing well without evidence of recurrence.

Primitive neuroectodermal tumor of the orbit in adults: a case series.

PURPOSE: To present the clinical, radiologic, and histopathologic features of orbital primitive neuroectodermal tumor (PNET) in 5 adult patients. METHODS: Retrospective case series of 5 adult patients with orbital PNET. Orbitotomy was performed in all cases. The authors report clinical findings, radiologic features, histopathology, immunohistochemical analysis, management, and outcomes for 5 patients with orbital PNET. RESULTS: Five adult patients presented with progressive unilateral proptosis and visual impairment. Common radiographic findings included a heterogeneous mass without associated destructive features, located in the superior and/or lateral orbit. Four cases demonstrated strong immunohistochemical staining for CD99 in a membranous pattern. One case required chromosomal analysis with fluorescence in situ hybridization to confirm the diagnosis. All patients received chemotherapy and/or orbital radiation with resolution of proptosis but no improvement of vision. One patient died of disease. CONCLUSIONS: To the authors' knowledge, this is the largest series of orbital PNET in adults. This tumor has an age demographic wider than previously believed and should be considered in the differential diagnosis of a hypercellular small round cell orbital tumor in both children and adults. Current treatment regimens are not standardized but typically use a similar approach to the treatment of Ewing sarcoma. Orbital PNET appears to have less propensity for metastasis compared with PNET in other locations. However, long-term aggressiveness remains to be proven.

Neuroectodermal ovarian tumors: a brief overview.

Primary neuroectodermal tumors of the ovary are rare monophasic teratomas composed exclusively or almost exclusively of neuroectodemal tissue. Approximately 60 neuroectodermal tumors of the ovary have been reported in the literature. These tumors were classified as ependymoma, astrocytoma, glioblastoma multiforme, ependymoblastoma or as primitive neuroepithelial tumors such as medullo-blastoma, medulloepithelioma and neuroblastoma. Most tumors were diagnosed in the third and fourth decades of life, but occasionally they were first discovered in children, adolescents or older women. Microscopically, they are identical to equivalent neuroectodermal tumors of the central nervous system. The review of the literature shows that most patients with clinical stage I and II were treated surgically, whereas those with stage III or IV tumors received additional radiation or chemotherapy, or both. The clinical stage at the time of diagnosis is the most important prognostic parameter of these tumors.

Uterine tumors with neuroectodermal differentiation: a series of 17 cases and review of the literature.

Uterine tumors with neuroectodermal differentiation, frequently referred to as primitive neuroectodermal tumors (PNETs), are uncommon. The clinicopathologic features of 17 such cases reviewed at the M.D. Anderson Cancer Center (MDACC) are presented along with a review of the literature. All of the pathology material was reviewed at MDACC, and in all cases, immunohistochemistry contributed to the diagnosis. In 12 cases, in situ hybridization techniques were used to determine whether a rearrangement of the EWSR1 gene, required for a diagnosis of peripheral PNET, was present. Clinical information was obtained from a patient chart review. Ages ranged from 31 to 81 years (median 58). Clinical presentations included vaginal bleeding (9), back pain (1), presumed fibroids (2), pelvic mass (1), incidental finding at hysterectomy (1), and unknown (3). Twelve patients had surgery or imaging to determine stage: I (2), II (0), III (6), and IV (4). Five patients had biopsy only. Ten tumors had only neuroectodermal components. In 7 tumors, the neuroectodermal component was admixed with an additional component including unclassified sarcoma (2 cases), rhabdomyosarcoma, endometrioid carcinoma, adenosarcoma and malignant mixed Mullerian tumor (2 cases). Follow-up, available for 13 patients, ranged from 2 to 41 months with 7 patients dead of disease 2 to 26 months after diagnosis. Six patients are alive with no evidence of disease after follow-up ranging from 6 to 41 months. Four patients were lost to follow-up. Results for the most commonly used immunohistochemistry studies include cytokeratin, 13/15 tumors negative (2 focally positive); synaptophysin, 15/16 tumors positive; neurofilament, 10/11 tumors positive; and CD99, 7/9 tumors positive (2 tumors had nonspecific cytoplasmic staining). None of the 12 tumors tested had a detectable rearrangement in the EWSR1 gene. Uterine tumors with neuroectodermal differentiation, similar to more common endometrial malignancies, tend to occur in postmenopausal women and frequently present with vaginal bleeding. An immunohistochemistry panel including cytokeratin, neurofilament, synaptophysin, and CD99 can highlight neuroectodermal differentiation and identify tumors for which molecular testing should be considered. Tumors without a rearrangement of the EWSR1 gene should be descriptively characterized as uterine tumors with neuroectodermal differentiation or alternatively central type PNETs rather than PNET, not otherwise specified to avoid confusion with peripheral PNET.

[Lung metastases in a primitive neuroectodermal tumor]. / Determinari secundare pulmonare în cadrul unei tumori neuroectodermale periferice.

Primitive neuroectodermal tumor (PNET) is a soft tissue sarcoma and is common among children and young adults. We present a case of a 27 years old woman with PNET localized at left arm and with lung metastases. Local ultrasound of the arm presented a tumor mass of 55/20 mm, computed tomography showed multiple pulmonary nodules in bilateral fields. The biopsy made during bronchoscopy and the biopsy made at arms level described PNET. CD99 markers was positive in both examinations.

Primary peripheral primitive neuroectodermal tumour of the orbit.

CASE REPORT: We present the clinical, radiologic, and histopathologic features of an orbital mass in a 10-year-old boy. Immunohistochemistry confirmed the diagnosis of primary peripheral primitive neuroectodermal tumour. COMMENTS: This recently recognized rare tumour of the orbit should be considered in the differential diagnosis of hypercellular small round cell tumour of the orbit.

Peripheral primitive neuroectodermal tumor associated with the anterior mandible: a case report and review of the literature.

Neuroectodermal tumors may arise in many places throughout the body including the diverse tissues of the head and neck. The primitive neuroectodermal tumor is a predominately neural, nonepithelial neoplasm similar to Ewing sarcoma. This article describes an 18-year-old female patient with a highly malignant peripheral primitive neuroectodermal tumor located in the soft tissue anterior to the mandibular symphysis. The clinical and radiographic presentation as well as the histopathology and immunohistochemistry of this rare entity is discussed. A review of the literature with respect to this tumor, as well as the current management of this tumor, is presented.

Keratin-positive Ewing's sarcoma: an ultrastructural study of 12 cases.

Ewing's sarcoma/primitive neuroectodermal tumor (EWS/PNET) is an aggressive neoplasm of bone and soft tissue. Histologically, it is characterized by the presence of small round blue cells, which usually express MIC-2 and FLI-1 immunohistochemically. The most specific feature for diagnosis, however, is cytogenetic or molecular evidence of a consistent abnormality, the t(11;22)(q24;q12), or variants thereof. The immunohistochemical expression of keratins in a significant proportion of these cases has been highlighted in several recent studies. The ultrastructural features of these keratin-positive tumors have not, however, been characterized in detail. In this study we analyzed the ultrastructural features of 12 well-documented EWS/PNETs that stained strongly for pankeratin by immunohistochemistry. Ultrastructurally, the tumor cells contained a few organelles, which included a small number of mitochondria, poorly developed Golgi complexes, free ribosomes, and inconspicuous rough-endoplasmic reticulum. Rudimentary cell junctions were seen in 2 tumors while prominent junctions were observed in the remaining 10. Five tumors contained intracytoplasmic filaments, and definite tonofibrils were identified in 2. Well-developed basal lamina around tumor cells were also demonstrated in 2 tumors. Follow-up information was available for all cases. Seven patients died of disease, 2 are alive with disease, and 3 have no current evidence of disease. The cohort includes 5 patients with a type-1 translocation, which has been associated with a better prognosis in some studies; 4 of these patients have died of their disease, and 1 is alive with recurrent disease. This study shows that keratin-positive EWS/PNETs have evidence of epithelial differentiation ultrastructurally, and may possibly represent a more aggressive subset of the EWS/PNET group of tumors.