|Year : 2018 | Volume
| Issue : 2 | Page : 41-43
Primitive neuroectodermal tumor of kidney and its rare affection for inferior vena cava
Kalyan Pandey, Bharat Bhusan Satpathy, Mohanlal Khadia, Padmalaya Devi
Department of Surgical Oncology, AHRCC, Cuttack, Odisha, India
|Date of Web Publication||21-Jun-2018|
Dr. Bharat Bhusan Satpathy
Department of Surgical Oncology, AHRCC, Cuttack - 753 007, Odisha
Source of Support: None, Conflict of Interest: None
Primitive neuroectodermal tumors (PNETs) are a group of small round cell malignancies of neural crest origin. Renal PNET (rPNET) is a rare entity affecting young adults and children with a poor prognosis, and involvement of inferior vena cava (IVC) is extremely uncommon. Nonspecific clinical features often preclude preoperative diagnosis which ultimately depends on microscopy and immunohistochemistry. The preferred treatment for rPENT is surgical resection associated with chemotherapy and radiotherapy. We report a case of rPNET in a 16-year-old male which was preoperatively thought to be of renal cell carcinoma and underwent radical nephrectomy with IVC venotomy. The case on histopathology study revealed features of malignant small blue round cell neoplasm and further immunohistochemical examination diagnosed the case as rPNET.
Keywords: Inferior vena cava, kidney, primitive neuroectodermal tumor
|How to cite this article:|
Pandey K, Satpathy BB, Khadia M, Devi P. Primitive neuroectodermal tumor of kidney and its rare affection for inferior vena cava. Oncol J India 2018;2:41-3
|How to cite this URL:|
Pandey K, Satpathy BB, Khadia M, Devi P. Primitive neuroectodermal tumor of kidney and its rare affection for inferior vena cava. Oncol J India [serial online] 2018 [cited 2019 Aug 20];2:41-3. Available from: http://www.ojionline.org/text.asp?2018/2/2/41/234904
| Introduction|| |
Primitive neuroectodermal tumors (PNETs) are a group of small round cell malignancies with neural crest origin and primarily affects bone and soft-tissue masses in the trunk and axial skeleton., The tumor commonly affects adolescents and young adults with a highly aggressive course.,,, PNET rarely presents as an organ-derived neoplasm. The overall incidence of peripheral PNET is 1% of all sarcomas. Renal PNET (rPNET) is extremely rare with few cases reported in the literature, and inferior vena cava (IVC) involvement is more rare. The diagnosis of rPNET is mainly based on histopathology and immunohistochemistry, supported by cytogenetic analysis; thus, preoperative diagnosis is challenging. Herein, we report a case of rPNET with IVC thrombus in a 16-year-old male.
| Case Report|| |
A 16-year-old male presented with 1-month history of mass per abdomen and 10 days history of hematuria and pain abdomen which on examination found to be a right lumbar mass of size approximately 10 cm × 8 cm, ballotable, and tender on deep palpation. Contrast-enhanced computed tomography (CECT) scan of abdomen showed the presence of a solid inhomogeneous enhancing mass of size 17.5 cm × 11.2 cm × 12.3 cm in the right kidney with calcific foci and necrotic areas, the tumor was extended into perirenal fatty tissue, right renal vein, and IVC with tumor thrombus in IVC, and there was the presence of mildly enlarged para-aortic node 10 mm × 9 mm [Figure 1]a and [Figure 1]b.
|Figure 1: Contrast-enhanced computed tomography scan on coronal section (a) and sagittal section (b) showing poorly marginated heterogeneous mass of size 17.5 cm × 11.2 cm × 12.3 cm in the right renal fossa almost replacing the entire renal parenchyma and the presence of mildly enlarged para-aortic lymph node with calcification on the sagittal section|
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A presumptive diagnosis of renal cell carcinoma was made and the patient was subjected to surgery. There was a large right renal mass compressing liver with IVC dilatation due to the tumor thrombus [Figure 2]a. Radical right nephrectomy was performed along with IVC venotomy and thrombus was removed [Figure 2]b. The postoperative course was uneventful and the patient was discharged on the 6th postoperative day.
|Figure 2: (a) Image showing intraoperative findings of tumor and dilated inferior vena cava and (b) image showing resected specimen|
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The sections studied from the renal tumor revealed an infiltrative malignant small blue round cell neoplasm with high mitotic and apoptotic index replacing the renal parenchyma [Figure 3]a. Multifocal coagulative tumor cell necrosis is seen. The neoplastic cells are arranged in sheets, clusters, and forming rosette with central eosinophilic neuropil-like material. Individual tumor cells are round with scant cytoplasm, evenly dispersed nuclear chromatin, smooth nuclear envelope, and inconspicuous nucleoli. No clear cell or papillary features is seen [Figure 3]b.
|Figure 3: Histopathologic image showing (a) tumor (right side) infiltrating the renal parenchyma (left side) (H and E, ×10) and (b) the typical morphology of a malignant small blue round cell tumor and rosette formation (H and E, ×40)|
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Based on the histomorphology, a rhabdomyosarcoma, Ewing's sarcoma/PNET family of tumor, desmoplastic small round cell tumor, adult Wilms' tumor (WT), and lymphoma were considered in the differential diagnoses. A battery of immunohistochemical markers was performed. The tumor cells exhibited diffuse and strong nuclear immunoreactivity for FLI1 [Figure 4]a. CD99 immunostain depicted cytoplasmic and membranous pattern of staining in a majority of neoplastic cells [Figure 4]b. Synaptophysin and CD56 revealed multifocal and cytoplasmic to membranous and strong positivity in the tumor cells [Figure 4]c and [Figure 4]d. However, pan-cytokeratin, CD45, WT1, desmin, myogenin, S100, myoD1, and chromogranin were negative in the neoplastic cells [Figure 5]a,[Figure 5]b,[Figure 5]c,[Figure 5]d. The above-mentioned immunohistochemical findings revealed the diagnosis of rPNET.
|Figure 4: Immunohistochemical examination (×20) showing the tumor cells exhibited: diffuse and strong nuclear immunoreactivity for FLI1 (a) and cytoplasmic to membranous pattern of staining with strong positivity for CD99 (b), CD56 (c), and synaptophysin (d)|
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|Figure 5: Immunohistochemical examination (×20) showing the tumor cells negative for CD45 (a), pan-cytokeratin (b), Wilms' tumor 1 (c), and desmin (d)|
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After the diagnosis of rPNET, the patient was referred to the medical oncology department for further plan of adjuvant chemotherapy. However, the patient was died on the 20th postoperative day at his resident place for which we were unable to know the cause of death.
| Discussion|| |
The small-cell tumors of the kidney are a heterogeneous group of neoplasms. The morphologic features of these tumors are overlapping but with different prognostic/therapeutic implications. Blastema-predominant WT, PNET, neuroblastoma, rhabdomyosarcoma, lymphoma, and desmoplastic round cell tumor are included under this group.
rPNET is a very rare entity and usually occurs in children and young adults with predilection toward males (male-to-female ratio of 3:1). The presentation of rPNET and its imaging features are nonspecific and similar to other renal tumors, making preoperative diagnosis difficult. However, the imaging features are useful for staging of the disease. Flank pain, abdominal mass, and hematuria are the common presenting symptoms. Patients usually present a large mass with a diameter of >10 cm at the time of diagnosis as in our case. CT images have no characteristic signs for rPNET and commonly reveal solitary, large, ill-defined, irregular, or lobulated heterogeneous mass. Magnetic resonance imaging of the rPNET shows a lobulated isointense and/or hypointense mass on T1-weighted images and a heterogeneous hyperintense mass on T2-weighted images.
The diagnosis of rPNET mainly depends on the combination of pathologic characteristics and biomarkers.
The macroscopic feature of the tumor on cut-open shows grayish white background with multiple areas of necrosis and hemorrhage. rPNET on microscopic examination shows small uniform round cells with dark nuclei, ill-defined cytoplasmic borders, and poorly formed rosette-like structures.,, These microscopic features overlap with other small round blue cell tumors such as neuroblastoma, desmoplastic small round cell tumor, and lymphoma. Immunohistochemistry and molecular studies play an important role in differentiating these tumors. rPNET is positive for different neural biomarkers such as S-100, Leu-7, and neuron-specific enolase., Positivity of MIC-2 gene product and CD-99 over the membrane of tumor cells is crucial in the diagnosis of rPNET and has been demonstrated in >90% of rPNET., Immunohistochemistry findings of rPENT are further supported by cytogenetic analyses, and the identification of a characteristic EWSR1/FLI1 fusion product with the translocation of t(11:22) (q2 4:Q12) has been detected in >90% of the rPNET.,,,,
rPNET behaves more aggressively than PNET arising at other sites. Distant metastasis occurs in approximately 20%–50% of patients at the time of presentation, and regional lymph nodes, bone, bone marrow, lung, and liver are the common possible sites for distant metastasis. The prognosis of rPNET is poor and the 5-year disease-free survival rate is about 45%–55% in localized disease, whereas an advanced stage at presentation has a median relapse-free survival of only 2 years.,
Surgical resection with adjuvant chemotherapy and radiotherapy are the preferred treatments for rPNET. Most of the patients undergo radical nephrectomy as the preferred surgical approach and the patients having associated thrombus should undergo additional cavotomy or thrombectomy. The most commonly used chemotherapeutic drugs are adriamycin, etoposide, vincristine, cyclophosphamide, and ifosfamide. The role of radiotherapy is controversial and may be required in locally advanced disease and in case of involvement of Gerota's fascia.,
rPNET should be considered as a differential diagnosis for suspicious renal mass in young adults. The diagnosis of rPNET should be based on histopathology and immunohistochemical analysis, supported by cytogenetic studies. Multimodality treatment strategies with surgery, chemotherapy, and radiotherapy are recommended for rPENT.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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