Primary Malignant Neuroepithelial Tumors of the Kidney

Abstract

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.

Molecular diagnosis of Ewing sarcoma/primitive neuroectodermal tumor in routinely processed tissue: a comparison of two FISH strategies and RT-PCR in malignant round cell tumors

“…1 The relationship between these tumor types has been studied extensively using immunohistochemical, genetic, and ultrastructural techniques leading to our current understanding of EWS/PNET as a highly cellular and monotonous primitive appearing neoplasm with a limited potential for neuronal differentiation, typically arising in the bone or soft tissue of individuals in the first few decades of life. 2 The EWS/PNET has overlapping morphologic features with other round cell tumors of childhood and adolescence. For prognosis and appropriate management, it is important to differentiate EWS/PNET from classic neuroblastoma, Wilms tumor, and rhabdomyosarcoma in particular.…”

Renal primitive neuroectodermal tumour in childhood: Case report and review of literature

“…The age range for this condition is from 4 to 61 years. 7 To our knowledge, our case is the fourth reported case in the pediatric age group; most of the reported cases occur with patients in their second or third decades of life. 12,13 The male to female ratio is about 3:1.…”

“…5 Renal PNET was first reported by Mor and colleagues. 6 There are only 4 reported series of renal PNET, which includes articles by Parham and colleagues, 7 Jimenez and colleagues, 8 Carlos and colleagues 9 and Yuvaraja and colleagues. 10 Renal PNET is extremely rare with fewer than 50 cases in the English literature.…”

“…The survival rate is poor and most patients die within 1 year of the diagnosis; although, in some of the previous reports, the 5-year disease-free survival rate was 45% to 55%. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Since PNET biologically behaves like Ewing's sarcoma, it should be treated with a combination of radical nephrectomy and chemotherapy, which includes vincristine, doxorubicin, cyclophosphamide, etoposide and ifosfamide. 27 In cases where there is an incomplete resection or positive margin or recurrence of the tumour, radiation is recommended.…”

Primitive Neuroectodermal Tumor of the Kidney with Hyaline Cells

“…So far PNET of the kidney has been described in only a few publications.In most cases, the tumor consists of small, round cells forming rosettes and pseudorosettes [2] . The differentiation of these tumors from other small cell cancers and neuroblastomas is based on immunohistochemical differences and molecular biological analysis [3] .…”