Primitive neuroectodermal tumor of the retroperitoneal cavity

Peripheral Primitive Neuroectodermal Tumor (Ppnet) of Pelvic Origin: Report of a Case Arising from an Unusual Location

A peripheral primitive neuroectodermal tumor arising from the abdominopelvic cavity is reported in a 24-year-old young male without any previous remarkable pathology. He was admitted to our hospital with complaints of urinary symptoms (acute urinary retention) and mild intestinal occlusion that had been present for three months. Physical examination and CT scan revealed a pelvic mass occupying the entire pelvic cavity. The diagnostic workup included a CT-guided biopsy which defined the tumor as a sarcomatous type. Radical surgery was performed including tumor resection, pelvic exenteration (bladder and prostate gland) and urinary and fecal diversion. Adjuvant chemotherapy (VAIA) was delivered once the histology was confirmed. We reviewed the available literature focusing on the varied nomenclature of this tumor (peripheral neuroepithelioma, Askin's tumor, Ewing's extraosseous tumor, peripheral adult neuroblastoma, peripheral primitive extracranial neuroectodermal tumor (PPNET), the clinical features, the role of diagnostic imaging techniques, pathologic assessment and controversial therapeutic management. In addition, the prognosis and survival of this rare condition were analyzed.

[Peripheral PNET of mesenteric location]

Les tumeurs neuroectodermiques primitives (PNET) mésentériques sont exceptionnelles. Elles appartiennent au groupe des tumeurs neuroectodermiques primitives périphériques et sont assimilées histologiquement aux sarcomes d'Ewing. Le diagnostic repose essentiellement sur les résultats immunohistochimiques et cytogénétiques. Nous nous proposons, à travers un cas de PNET à localisation mésentérique de revoir l'ensemble des aspects cliniques, radiologiques, histopathologiques et thérapeutiques de ce groupe de tumeur.

Primary primitive neuroectodermal tumor of the cervix confirmed with molecular analysis in a 23-year-old woman: A case report

Primitive Neuroectodermal Tumor (PNET) of the genital tract is very rare, especially in the cervix. A case report of a young woman with a diagnosis of PNET originating from the uterine cervix is presented here. A 23-year-old woman presented with abnormal uterine bleeding and sharp lower abdominal pain of two months duration. CT and MRI of the abdomen and thorax revealed the presence of a large mass in the uterine cervix, enlarged pelvic lymph nodes and broncho-pulmonary infiltrations with regional nodes. Pathological examination of the tumor revealed a malignant neoplasm composed predominantly of small cells, immunohistochemically positive for CD99, vimentin and c-Kit. Molecular testing demonstrated the expression of EWS/FLI1 fusion transcripts corresponding to the t(11;22)(q24;q12) translocation, which confirmed the diagnosis of PNET of the uterine cervix. Despite surgical excision and administration of the first cycle of adjuvant chemotherapy, the patient died from multiple-organ failure and cardiac arrest. PNET arising from the genital tract, especially in the uterine cervix, is very rare and presents a diagnostic challenge. A timely confirmation with molecular analysis is essential for the diagnosis of such a tumor at an unusual site as in the present case.

Primary Ewing's sarcoma-primitive neuroectodermal tumor of the uterus: a case report and literature review

BACKGROUND

Primary Ewing's sarcoma-primitive neuroectodermal tumor (ES-PNET) of the uterus is an extremely rare malignancy.

CASE

A 30-year-old Korean woman presented with abnormal uterine bleeding with uterine enlargement. A computed tomography (CT) scan and magnetic resonance imaging (MRI) of the abdomen and pelvis showed a huge uterine mass measuring 18 x 20 x 21 cm, metastasis to both pelvic and para-aortic lymph nodes, and omental infiltration. The pathology report of the uterine mass described a uniformly hypercellular tumor, which was arranged in diffuse solid sheets of uniform, small, rounded, and sometimes spindle-shaped cells, with scanty cytoplasm. Immunohistochemically, the mass tested positive for vimentin, CD99, and chromogranin. The patient received several courses of combination chemotherapy and radiotherapy but died from tumor progression 16 months after the initial diagnosis.

CONCLUSION(S)

This is a rare case of primary uterine ES-PNET in a woman of reproductive age. A review of the literature indicates that primary uterine ES-PNET requires early diagnosis and multimodality treatment including surgery, chemotherapy, and radiotherapy. The behavior of this tumor is potentially aggressive.

Peripheral Primitive Neuroectodermal Tumor (PPNET) of Pelvic Origin: Report of a Case Arising from an Unusual Location

We report a rare case of a peripheral primitive neuroectodermal tumor (PPNET) originating from the left ileopsoas muscle in an adult patient with neoplastic thrombosis of the left external iliac vein, the common femoral vein and the left popliteal vein. We performed a median laparotomy with an oblique left inguinal incision to remove the neoplasm, which consisted of a large mass surrounding the iliac-psoas muscles, extending from the transverse apophysis of the spinal column to Scarpa's triangle, and passing through the lacuna musculorum. Histopathological examination revealed a primitive neuroectodermal tumor (PNET) with focal areas of necrosis, hemorrhage and vascular invasion. Immunophenotyping was positive for CD99, NSE, and focally for CK. Ultrastructural examination of the neoplastic cells showed often multiple nuclei with dense chromatin and very large nucleoli. The patient was discharged ten days after the operation. Adjuvant treatment consisted of radiotherapy at a dose of 2000 cGy in five fractions followed by six cycles of chemotherapy. The venous thrombosis was treated by anticoagulant therapy and recanalization of the occluded veins was obtained after two months of therapy. An MRI scan, carried out 12 months later, showed a local relapse, which was treated with chemotherapy and arterial chemoembolization.

Cervical primitive neuroectodermal tumor

BACKGROUND

Primitive neuroectodermal tumors (PNETs) are rare and potentially aggressive malignancies.

CASE

A 24-year-old woman in her eighth week of pregnancy presented with a cervical mass. Tissue biopsy demonstrated poorly differentiated carcinosarcoma with neuroendocrine features. Immunohistochemical studies confirmed the diagnosis of PNET. Treatment included alternating courses of cyclophosphamide, adriamycin, vincristine (CAV) and ifosfamide, etoposide (IE). A radical hysterectomy with bilateral ovarian transposition and periaortic lymphadenectomy was performed with postoperative chemotherapy and radiotherapy. The patient remains disease free 2 years from therapy.

CONCLUSION

This is a rare case of cervical PNET occurring in a pregnant patient. A review of the literature indicates that cervical PNET is distinguishable from uterine PNET. This tumor affects younger women and may have a different histogenesis. Pregnancy should not delay diagnosis of this potentially aggressive tumor.

Primary primitive neuroectodermal tumor of the kidney

Primitive neuroectodermal tumor (PNET) is a small round cell sarcoma that mainly develops in the central nervous system and soft tissues of childhood; however recently, primary occurrence of this tumor in the kidney has been reported. We experienced one case of PNET primarily arose in the kidney without metastasis. The patient was a 28-year-old man whose chief complaint was abdominal pain, especially on exercise. On computed tomography scan and magnetic resonance imaging, a solid lesion was found in the left kidney, and a left nephrectomy was performed based on the diagnosis of a tumor in the left kidney. The tumor was within the parenchyma of lower end of left kidney protruding into the abdominal cavity. Histologically, diffuse proliferation of primitive small round cells with rosette formation was found. Immunohistochemically, MIC2 gene product, neuron-specific enolase and S-100 protein were positive. No metastasis to the regional lymph nodes was found. From these observations, the tumor was diagnosed as PNET primarily arising in the left kidney. Although chromosome analysis was not performed, EWS-FLI1 chimera gene was identified by reverse transcriptase-polymerase chain reaction on the freshly frozen specimen and fluorescence in situ hybridization on paraffin sections.

Primary primitive neuroectodermal tumour of the parotid gland

AIMS

Primitive neuroectodermal tumour (PNET) is a malignant small round cell tumour that exhibits neuroepithelial differentiation. Isolated cases of PNET have been reported in visceral sites such as the kidney, uterus, ovary, testis, urinary bladder and pancreas. We present two cases of PNET of the parotid gland.

METHODS AND RESULTS

The first case was a 60-year-old woman, who presented with a parotid swelling of 10 months duration. The second case was a 45-year-old man, who presented with a recurrent temporofacial swelling of 6 months duration. Histological evaluation, in conjunction with immunohistochemistry, confirmed the diagnosis of PNET.

CONCLUSIONS

This is the first documentation of PNET of the salivary gland. The probable origin is from the facial nerve.

Computed tomography of abdominal neurogenic tumours

Abdominal and pelvic neurogenic tumours are uncommon neoplasms in adults apart from those tumours found in patients with neurofibromatosis. Malignant degeneration occurs in 2.4-29% of neurofibromatosis. Biopsy of neurofibromas can be complicated by sensorimotor nerve deficit. Distinction of malignancy by imaging may circumvent biopsies of asymptomatic benign neurogenic tumours. Benign neurogenic neoplasm is suspected on CT scan if the tumour is in the region of known nerve ganglia or pathway, and is well demarcated, solid, homogeneous, hypodense relative to muscle, and enhances with contrast material. Malignant neurogenic tumours are often large, irregular, infiltrative, and necrotic with heterogeneous contrast enhancement. Computed tomography is valuable in distinguishing malignant from benign neurogenic neoplasms, predicting resectability, detecting distant metastases, and evaluating response to treatment.

Collision tumor: a peripheral neuroepithelioma and a transitional-cell carcinoma occurring simultaneously in the renal pelvis

We report a unique case of a collision tumor of the kidney composed of a peripheral neuroepithelioma (PNE) and a transitional cell carcinoma (TCC) that occurred in a 67-year-old man with a long history of superficial TCC of both the bladder and bilateral upper urinary tracts. The PNE was composed of hyperchromatic, small, round cells, arranged in clusters and poorly cohesive sheets. Immunohistochemical studies revealed the small cells to be strongly positive for O13 (ie, a MIC2 gene product stain [CD99]) and vimentin. Electron microscopic examination found numerous interdigitating cell processes, multiple poorly formed cell-cell junctions, and dense-core granules. The latter were most conspicuous at the tips of the cell precesses. The PNE cells were clearly negative for cytokeratin, and they showed no transitional or intermediate features that would suggest evolution of the PNE from the adjacent TCC. The proximity of these two tumors appears to be serendipitous; thus, it can be considered a true collision tumor of the kidney.

EWS/FLI-1 fusion transcripts in three peripheral primitive neuroectodermal tumors of the kidney

Although primitive neuroectodermal tumor (PNET) is a well-recognized entity, its renal localization as a primary site has not been appreciated. Only nine cases of renal PNET exist in the literature. The paucity of renal PNET could be explained by the lack of objective diagnostic techniques that would facilitate its distinction from other primitive round cell tumors of the kidney, such as the more widely recognized monophasic Wilms' tumor and clear-cell sarcoma of the kidney (CCSK), as well as renal carcinoid, or neuroblastoma invading the kidney from the adjacent adrenal gland. The recently identified specific fusion transcripts detectable by reverse transcription polymerase chain reaction (RT-PCR) have provided us with a valuable tool for the detection of renal PNET. This article reports three renal PNET that expressed EWS/FLI-1 fusion transcripts by RT-PCR, in addition to positive staining for MIC2 protein and neuron-specific enolase (NSE). One also exhibited dense core granules in cell processes by electron microscopy. Employment of such methodology will lead to a more accurate classification of renal tumors.

Establishment of a human cell line secreting neuron-specific enolase from a primitive neuroectodermal tumor of the retroperitoneal cavity

Primitive neuroectodermal tumor (PNET) is one of the small round cell malignancies of presumed neural crest origin for which an effective treatment has not yet been established. In the present study, a human cell line, designated KU-9, was established from a 27-year-old male patient with PNET of the retroperitoneal cavity and has been successfully maintained in nude mice and in culture. On histological examination, the primary tumor was composed of poorly differentiated small round cells arranged in clusters showing a variety of mitotic changes, and contained Homer-Wright rosettes. The histopathological appearance of the KU-9 xenografts was similar to that of the primary tumor. Electron microscopy revealed neurosecretory granules and cytoplasmic processes in the xenograft. No significant amplification of N-myc gene was observed in the KU-9 cells. The KU-9 cells showed chromosome numbers ranging from 56 to 61 with consistent structural abnormalities being add(2)(q31), +add(11)(p11.2), +add(13)(p11.1), and +del(22)(q12). Cultured KU-9 cells grew exponentially with a doubling time of about 50 h and a time-dependent increase in medium levels of neuron-specific enolase (NSE) was noted. Serum levels of NSE in KU-9 tumor-bearing nude mice were significantly elevated and a linear relationship between the serum NSE levels and the tumor NSE content or tumor volume was observed, suggesting that serum levels of NSE may reflect the PNET tumor burden and tumor extent. These results indicate that the KU-9 cell line provides a reproducible model system which could be useful in gaining some insight into the histogenesis and oncogenesis of PNET and in establishing an effective treatment for PNET.