Alveolar rhabdomyosarcoma in children with histomorphological review.

Rhabdomyosarcomas (RMS) are aggressive malignant neoplasm of mesenchymal origin, related to skeletal muscle lineage. These are the most common soft tissue tumors in children. The diagnosis is made by microscopic analysis and ancillary techniques like immunohistochemistry, electron microscopy, cytogenetics and molecular biology. We encountered a case of a 03 years old child who presented with a tender, reddish, soft swelling over cheek for three weeks. The FNAC was reported as a small round cell tumor, Probably Primitive Neuroectodermal Tumor (PNET). The biopsy of tumor revealed a small round cell tumor with an alveolar pattern. Tumor giant cells were absent and mitotic figures were infrequent. Hence, differentials of alveolar rhabdomyosarcoma and PNET were rendered. Immunohistochemistry (IHC) demonstrated desmin positivity. Thus, a final diagnosis of alveolar rhabdomyosarcoma was offered.

Primary Primitive Neuroectodermal Tumor of the Breast: a Case Report

Primary primitive neuroectodermal tumors (PNET) are rare malignant tumors, affecting mostly children and adolescents. Only three cases of primary breast PNETs have been reported in the medical literature, with none in Korea. We present a case of a primary PNET of the breast in a 33-year-old woman, with imaging and immunohistopathology findings.

Primitive Neuroectodermal Tumor of the Kidney / 대한비뇨기과학회지

Primitive neuroectodermal tumor (PNET), also referred to as extraskeletal Ewing's sarcoma, is a highly aggressive tumor, and it is seen typically in the soft tissues of the chest wall and paraspinal region but rarely arises in the kidney. A 27-year-old woman was presented with a left renal mass and underwent a radical nephrectomy. The pathological diagnosis was a primitive neuroectodermal tumor. Microscopically, there were sheets and lobules of cells with round to oval nuclei and coarse chromatin, as well as a Homer Wright rosette formation. Immunohistochemical analysis showed strongly positive staining of CD99 and negative staining of other neuroendocrine markers, such as synaptophysin and chromogranin.

Primary peripheral primitive neuroectodermal tumor of the ovary with an epithelial cyst : A case report and review of literature.

Peripheral primitive neuroectodermal tumor (pPNET) has some histologic resemblance to a classic central primitive neuroectodermal tumor (cPNET), however it is distinctively different from cPNET by its CD99 immunoreactivity, characteristic chromosomal translocation, t(11;22)(q24:q12) and EWS/FLI-1 chimeric mRNA. Peripheral PNETs have a predilection for soft tissues rather than for viscera. Only 15 cases of primary ovarian PNET have been reported, and only one case was proven to be pPNET. Ovarian PNET is an aggressive tumor. We report a case of a 40-year-old Thai woman with a Stage IIIb right ovarian PNET is an aggressive tumor. Despite debulking operation and vigorous adjuvant chemotherapy, the patient died of disease 6 months later. Grossly, the tumor was solid and cystic. Microscopically, the former displayed unique features mimicking cPNET, but the pPNET phenotype was validated by CD99 staining. The solid portion also contained mucin-producing gland-like structures, previously described as ependymal diffentiation. In the cystic portion, the histology demonstrated epithelial linning tissue resembling cystadenoma of borderline malignancy of the ovary. It is generally accepted that both cPNET and pPNETs can have polyphenotypic differentiation. PNETs can be originated from either totipotential germ cells, neural crest remnant or mullerian-derived cells.

Primitive Neuroectodermal Tumor of the Kidney with CD99 Positive Staining / 대한비뇨기과학회지

Primitive neuroectodermal tumors (PNETs) are primitive neuroblastic tumors that, unlike neuroblastomas, arise outside the autonomic nervous system, but very few cases with a renal origin have been described. The immunohistochemical staining for CD99 is useful in their diagnosis. A case of renal primitive neuroectodermal tumor, in a 61- year-old man presenting with a painless gross hematuria is reported. The immunohistochemical staining of the renal mass was strongly positive for CD99.

Primitive Neroectodermal Tumor in the Cauda Equina Region

We report a malignant peripheral primitive neuroectodermal tumor (PNET) that originated in the cauda equina in a young adult, After gross total excision of the tumor, radiotheraphy was followed. The tumor had the typical appearance of a PNET with small, round cell. It stained positively for the neuron-specific enolase(NSE) conforming its neural origin and negatively for cytokeratin, glial fibrillary acidic protein(GFAP ) and S-100 protein. Three months later, MRI showed almost total obstruction at the level o f the L/L interspace caused by a mass occupying the spinal canal and extending into the L/S foramen on the right. Sixteen months after commencement of radiotherapy, severe left sciatica developed and MRI showed involvement of the both ilii and right femur with a large soft tissue mass extending into the pelvis. Palliative radiotherapy was administered but the patient died four months later.

Primitive Neuroectodermal Tumor of the Kidney: A case report

Peripheral primitive neuroectodermal tumor (pPNET), a rare, highly aggressive neoplasm of indetermined histogenesis, occurs typically in the soft tissues of the chest wall and the paraspinal region. Comprehensive diagnostic studies including histological, ultrastructural, immunohistochemical and molecular analyses have been stressed to diagnose this entity. We report a case of primary renal PNET which was incidentally found in a 59-year-old man who presented with generalized weakness for 4 months. He was diagnosed as a non-insulin dependent diabetes mellitus 15 years ago and has been made well by oral therapy. An ill-defined mass, measuring 3.5 3 cm, located in the left kidney and perirenal fat, was incidentally found by ultrasonogram during a renal diabetic examination. The mass was resected because of the unresponsiveness against one-year chemotherapy and radiation therapy. Grossly, a homogeneously solid, gray-white mass, measuring 2.8 1.8 cm, was noted in the mid portion of renal cortex. The mass showed severe adhesion to the perirenal fatty tissue. Microscopically, tumor cells were rather uniform, small round with scanty cytoplasm and often showed rosette formation. Ultrastructurally, they showed membrane-bound dense core granules, measuring 125~150 nm, intercellular junctions and microvillous cytoplasmic projections. The tumor cells were uniformly immunoreactive for neuron-specific enolase and were focally immunoreactive for CD99 (013), chromogranin, synaptophysin and cytokeratin. They were not reactive for S-100 protein, vimentin, Leu-7, leukocyte common antigen, desmin and smooth muscle actin. To our knowledge, this is the smallest renal PNET in literature.

Pathologic Study of Primitive Neuroectodermal Tumor: Report of 5 cases

Primitive neuroectodermal tumor (PNET) occuring in the brain (especially in the cereburm) of young individuals is a rare and highly malignant neoplasm. The authors analyzed 5 cases of primitive neuroectodermal tumor, operated from January 1986 to September 1987. They had characteristic clinical, radiologic and pathologic features. Patient's age ranged from 2 years to 14 years old (mean 8.2 years old) and there were 3 boys and 2 girls. They were rapidly growing tumor, with a brief duration of symptoms taking a rapidly progessive course. Computerized tomographic findings were characteristic, revealing the large, irregular, typically iso-to hyper-dense mass lesions with calcification and cystic or necrotic areas, and showing dense heterogeneous contrast enhancement of the mass in the cerebral hemisphere. Grossly all of the 5 cases showed hemorrhage and necrosis with sharp border and 2 cases showed calcification and cystic change grossly. Microscopically, they were predominantly composed of undifferentiated small dark cells with evidence of focal differentiation along glial and or neuronal lines. Four cases showed glial differentiation and three cases showed neuronal differentiation. Mesenchymal components were predominant in 3 cases.