Desmoplastic Small Round Cell Tumor of the Kidney in a Pediatric Patient: Sonographic and Multiphase CT Findings

Desmoplastic Small Round Cell Tumor of the Kidney: Report of a Case, Literature Review, and Comprehensive Discussion of the Distinctive Morphologic, Immunohistochemical, and Molecular Features in the Differential Diagnosis of Small Round Cell Tumors Affecting the Kidney

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive neoplasm typically presenting with widespread involvement of the abdominopelvic peritoneum of adolescent males, usually without organ-based primary. Although it is believed to originate from the serous (mainly peritoneal) membranes, intracranial, sinonasal, intraosseous, and other soft tissue sites are also documented. A chromosomal translocation t(11:22)(p13;q12) signature that fuses EWSR1 and WT1 genes results in the production of a chimeric protein with transcriptional regulatory activity that drives oncogenesis. Integration of clinical, morphologic, immunohistochemical, and genetic data is necessary to arrive at the correct diagnosis, especially when the tumor arises in an atypical site. A 15-year-old male presented with hematuria and was found to have a large renal tumor associated with adrenal, liver, lung, and bone metastases. Histopathologic and immunophenotypic features were distinctive for DSRCT. This diagnosis was confirmed by means of fluorescence in situ hybridization and cytogenetic analysis, which documented the pathognomonic t(11;22) translocation, and by reverse transcription polymerase chain reaction on snap-frozen tissue, which revealed the EWSR1/WT1-specific chimeric transcript. Despite high-dose chemotherapy and radiation therapy targeted to a single T11 vertebral metastasis, the disease progressed, and the patient died 4 years after the diagnosis. A search of electronic databases for DSRCT yielded 16 cases of well-documented renal primaries out of around 1570 cases from all sites gathered from the global literature. Desmoplastic small round blue cell tumor and other primary renal tumors considered in the differential diagnosis with DSRCT are discussed.

Desmoplastic small round cell tumor of the kidney: a case report

Background

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive neoplasm seen in children and young adults, usually manifested by involvement of abdominal serosa. Here, we present an unusual case of primary DSRCT of kidney.

Case presentation

The patient was an 8-year-old girl with a large renal mass which was confused with primitive neuroectodermal tumor (PNET) in the needle biopsy. The tumor had a variegated histology revealing frequent pseudo-rosette formations, pseudopapillary architecture, rhabdoid, clear or pleomorphic cells in addition to typical small round cell morphology and desmoplasia. It showed immunohistochemical features of DSRCT, and EWSR1 re-arrangement.

Conclusions

Proffering this diagnosis is particularly difficult for tumors of viscera because of the incognizance of the entity in these locations. Moreover, DSRCT is a great mimicker and may get easily confused with more common kidney malignancies of childhood such as Wilms tumor, PNET/EWS, rhabdoid tumor, clear cell sarcoma, and other small round cell tumors as well as renal cell carcinomas. The distinction is critical as the accurate therapeutic approach will require correct diagnosis.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade: From the Radiologic Pathology Archives

Malignant renal tumors account for 7% of childhood cancers, and Wilms tumors are by far the most common-but not in older children and adolescents. Among individuals in the latter half of their 2nd decade of life, renal cell carcinoma (RCC) is more common than Wilms tumor. The histopathologic spectrum of RCCs in children differs from that in adults. The most common subtype of RCC in children and adolescents is Xp11.2 translocation RCC, which is distinguished by hyperattenuation at nonenhanced computed tomography, a defined capsule, and associated retroperitoneal lymphadenopathy. Papillary RCC is the second most common histologic subtype. It enhances less intensely compared with the adjacent renal parenchyma and has a propensity for calcification. Clear cell RCC is seen in patients with von Hippel-Lindau disease and is distinguished by its relatively hypervascular nature. Medullary carcinoma affects adolescents with the sickle cell trait and is characterized by an infiltrative growth pattern and extensive metastasis at presentation. Angiomyolipoma is seen in children with tuberous sclerosis complex and is often multifocal and hypervascular, with macroscopic fat. Metanephric tumors are central, circumscribed, and typically calcified. Lymphoma usually manifests as multifocal masses, but it may involve a solitary mass or infiltrative pattern. Extensive adenopathy and involvement of the gastrointestinal tract or other organs also may be seen. Primitive neuroectodermal tumor is an aggressive neoplasm that is typically quite large at diagnosis. Knowledge of the clinical, biologic, and histopathologic features of renal tumors in older children and adolescents and their effects on the imaging appearance can help the radiologist offer a useful preoperative differential diagnosis.

An approach to renal masses in pediatrics

Renal masses in children may be discovered during routine clinical examination or incidentally during the course of diagnostic or therapeutic procedures for other causes. Renal cancers are rare in the pediatric population and include a spectrum of pathologies that may challenge the clinician in choosing the optimal treatment. Correct identification of the lesion may be difficult, and the appropriate surgical procedure is paramount for lesions suspected to be malignant. The purpose of this article is to provide a comprehensive overview regarding the spectrum of renal tumors in the pediatric population, both benign and malignant, and their surgical management.

Effectiveness of the new injection program 'saline test injection mode' for use power injector in pediatric contrast CT

To improve the safety of the use of a power injector for pediatric contrast CT, we newly developed a saline test injection mode for a power injector and investigated its usefulness. We used an injection route and investigated the relationship of the injection pressure to the injection rate of saline and the contrast medium. From this relationship, we investigated it was possible to estimate the change of pressure injection of contrast medium from the pressure change of saline injection. The correlation between the saline test injection pressure and the contrast medium injection pressure was investigated in 64 clinical cases. The detection rate of side effects from the saline test injection was investigated in 473 patients. Regarding the correlation between the injection rate and pressure for both saline and contrast, the pressure rose as the rate increased. The contrast medium injection pressure could be estimated from the correlation observed with saline. The clinical data were obtained had a relationship similar to that with phantom data. The detection rate of side effects from the saline test injection was 4.4% in the clinical cases. In these cases, examinations were completed by re-establishing an injection route or administering hypnotics. Our results suggest that contrast medium pressure can be estimated from a saline test injection, thus aiding in prediction of the risk of injection abnormality. Reactions to injections could be observed in the present study, facilitating the prevention of examination failure. Countermeasures can be taken against the cause of the reaction, and the examination can be performed after confirming the absence of a reaction to injection. Therefore, a saline test injection may be useful in pediatric contrast CT.

WARM N COLD: malignant and benign renal tumors in children

Although Wilms tumor is the most common renal malignancy in children, the differential diagnosis is extensive and includes both malignant and benign disorders. We present a simple mnemonic-WARM N COLD, to aid in remembering these diverse tumors. Imaging clues including age of the patient, associated disease or syndrome as well as salient imaging characteristics such as bilaterality, and type or presence of metastasis are also presented and can help differentiate between these renal tumors of childhood.

Imaging of pediatric desmoplastic small-round-cell tumor with pathologic correlation

Desmoplastic small-round-cell tumors are rare aggressive malignancies that belong to the "small round blue cell" tumor family. They predominantly affect the abdomen in adolescent and young adult males. Computed tomography is currently the modality of choice both for diagnosis and follow-up assessment. In this review, the authors provide a concise yet comprehensive discussion of this condition with emphasis on the imaging findings. Pathologic correlation, differential diagnostic considerations, and treatment will also be presented.

Clinicopathological investigation of four cases of desmoplastic small round cell tumor

The purpose of this study was to perform clinicopathological and immunohistochemical analysis and to investigate the Ewing sarcoma gene (EWS)-Wilms' tumor suppressor gene (WT1) fusion within desmoplastic small round cell tumors (DSRCTs). Histology slides and clinical data were reviewed for four patients with DSRCT. A variety of immunohistochemical staining was performed. Fluorescence in situ hybridization (FISH) was performed to detect the EWS-WT1 fusion transcripts resulting from the chromosomal translocation t(11;22)(p13;q12). The patients consisted of four males aged from 26 to 52 years old (mean, 33.5). In three of these patients, the tumors were situated in the abdominal cavity and the tumor from the other patient was located in the pelvic cavity. The tumors were 8-15 cm in diameter (mean tumor diameter, 13), solid and gray-white, with an appearance of nodosity or sublobes, and hemorrhage or necrosis was observed. Microscopically, the tumors consisted of small round cell nests of unequal size. Hyperplastic and thick fibrous connective tissue surrounding the neoplastic cell nests was present in all cases. The tumor nuclei were hyperchromatic and contained inconspicuous nucleoli with a high level of karyokinesis. Immunohistochemical staining revealed diffuse and strong staining for CK, vimentin, desmin and CAM5.2 in all cases. Certain cases also expressed WT-1, EMA, NSE, CD56, CD99 and CK5/6. Staining was negative for myogenin, MyoD1, calretinin, CD117, CD34, HMB45 and CEA. EWS-WT1 fusion transcripts were detected in 3 out of 4 cases, but not in any other tumor types studied as controls using paraffin-embedded tissue by FISH. DSRCT is a highly maligant tumor occuring predominantly in the abdominal or pelvic cavity of young males with multiphenotypic differentiation. Basic morphological features, clinical manifestations and the detection of the EWS-WT1 fusion transcript within the tumor aid the recognition and diagnosis of the tumor.

CT imaging of mass-like renal lesions in children

Mass-like renal lesions in children occur in a diverse spectrum of conditions including benign and malignant neoplasm, infection, infarction, lymphatic malformation, and traumatic injury. Although mass-like renal lesions can sometimes be suspected on plain radiographs and evaluated with US in children, subsequent CT is usually performed for the confirmation of diagnosis and further characterization. The purpose of this pictorial essay was to review the CT imaging findings of both common and uncommon mass-like renal lesions in pediatric patients. Understanding the characteristic CT appearance of mass-like renal lesions in children enables an accurate diagnosis and optimizes patient management.

Primary desmoplastic small round cell tumor of the kidney: a case report in a 14-year-old girl with molecular confirmation

We report a case of desmoplastic small round cell tumor (DSRCT) arising in the kidney of a 14-year-old female. The subject presented with gross hematuria. Medical imaging uncovered a left renal mass without regional or metastatic extension. The tumor showed morphological, immunohistochemical, and molecular features of DSRCT. Immunostaining revealed polyphenotypic differentiation. Molecular analysis detected the fusion transcript resulting from the t(11;22)(p13;q12) reciprocal translocation, which characterized this neoplasm. Desmoplastic small round cell tumor is a rare, aggressive neoplasm that mainly affects young males and that usually presents with widespread abdominal serosal involvement. This unusual localization should lead one to consider this tumor in the differential diagnosis of small blue round cell tumors of the kidney.