Cytologic characteristics of clear-cell sarcoma of the kidney (CCSK) in fine-needle aspiration biopsy (FNAB): a report of 4 cases

Clear cell sarcoma of the kidney: a review

Clear cell sarcoma of the kidney (CCSK) is a rare renal tumour that is observed most often in children under 3years of age. Only a few large series of CCSK have been reported and patients with CCSK are often included among patients with other types of childhood renal tumours. The purpose of this paper is to review the published series and case reports of CCSK and to create an up-to-date overview of clinical and histological features, genetics, treatment, and outcome.

Part I: Primary malignant non-Wilms' renal tumours in children

Non-Wilms' tumours form a small heterogeneous group of clinically significant renal malignancies in children, including renal-cell carcinoma, clear-cell sarcoma, (congenital) mesoblastic nephroma, rhabdoid tumour, and renal medullary carcinoma. Good progress has been made in the assessment of these tumours, which has led to a greater understanding of the molecular changes that occur in their development. This review is the first of two parts, and provides an updated review of the clinical presentation, imaging, and pathology of these tumours.

Fine-needle aspiration biopsy in pediatric oncology patients: a review of experience with 829 patients (899 biopsies)

The authors review their 20-year (1985-2004) experience with fine-needle aspiration biopsy (FNAB) in 829 children (all but 1 younger than 18 years), from whom 899 samples were obtained. All patients presented with clinical data suggesting malignancy. The procedure followed standard methods (22- to 24-gauge needle; mean of six alcohol-fixed and/or air-dried, H&E- or Giemsa-like-stained smears/procedure; leftover clots processed as a biopsy). Interpretation of cytologic smears was performed taking into consideration the clinical, laboratory, and imaging data. Smears diagnosed as positive for malignant cells were reported in 510 samples (56.7%) (463 patients); 1.89% of the smears were found inadequate for diagnosis. Positive for malignancy cases included 467 primary tumors, 52% of which were localized to the abdomen. NMYC status was determined on neuroblastoma samples by fluorescent in situ hybridization. Overall sensitivity of the procedure was 98% (500/510 FNAB); specificity was 92.6% (463/500 FNAB); positive predictive value was 1 and negative predictive value was 0.99. All FNABs diagnosed as benign tumors or inflammatory lesions correlated with histology and/or clinical outcome. FNAB proved to be highly cost-effective, avoiding a surgical biopsy. The procedure was found to be extremely helpful when deciding on preoperative chemotherapy.

Cytopathology of uncommon malignant renal neoplasms in the pediatric age group

Malignant renal neoplasms are common solid tumors in pediatric oncology practice. These include the common Wilms' tumor/nephroblastoma and the uncommon neoplasms such as clear-cell sarcoma of the kidney (CCSK), rhabdoid tumor, renal-cell carcinoma, and others. The aim of this study was to describe in detail the cytopathological features of the histopathologically proven uncommon pediatric renal tumors. Aspirates from Wilms' tumor, which are mesenchyme predominant, show clusters of spindle cells associated with the matrix material. Evidence of rhabdomyoblastic differentiation may be present. CCSK, classic subtype, is characterized by round to oval cells arranged perivascularly and also in sheets and clusters intimately associated with a metachromatic matrix mucopolysaccharide material better appreciated in May-Grunwald-Giemsa (MGG)-stained smears. The cells also have more abundant cytoplasm and may show nuclear grooves. Spindle-cell pattern of CCSK is difficult to diagnose on aspiration cytology. Renal-cell carcinoma of childhood shows similar cytological features as its adult counterpart. Rhabdoid tumor of the kidney is characterized by a monomorphic population of cells with abundant cytoplasm, eccentric nuclei with prominent nucleoli. Intrarenal yolk sac tumor is a rare neoplasm and shows severely pleomorphic cells on aspiration. Awareness of these entities is important for the practicing cytopathologist. Further, non-Wilms' renal malignant neoplasms must be distinguished from the common Wilms' tumor so that appropriate chemotherapy protocols may be instituted in cases where the tumor is in an advanced stage of malignancy.

Fine-needle aspiration cytology of clear-cell sarcoma of the kidney: Study of eight cases

The largest series, to date, of fine-needle aspiration cytology (FNAC) findings in clear-cell sarcoma of the kidney (CCSK) is presented. All fine-needle aspirates of pediatric renal masses over a 17-yr period were reviewed. Eight out of 119 aspirates from late-stage childhood renal tumors (6.72%) were found to be CCSK. Ten aspirates from these eight patients and histopathological confirmation in six patients were available. Aspirates were cellular with three cell types: cord cells, septal cells, and small pyknotic cells. Cord cells, seen in all aspirates, were large polygonal cells with abundant eccentrically placed wispy cytoplasm, round to oval nuclei, and fine dusty chromatin. Occasional bare nuclei and frequent nuclear grooves were also seen. Small pyknotic cells were a degenerative change identified in 9 out of 10 aspirates. Stromal fragments with branching vascular cores were seen in 8 out of 10 aspirates, 6 of which had myxoid substance surrounding the vessel. Septal cells were spindle shaped and usually embedded in the stromal fragments. On the basis of cytology and histology, cases were classified into classical CCSK (5 cases), spindle-cell CCSK (1 case), and anaplastic CCSK (2 cases). Classical CCSK showed mostly cord cells with few stromal fragments. Spindle-cell CCSK showed preponderance of myxoid stromal fragments and septal cells. Anaplastic CCSK showed bizarre pleomorphic nuclei, coarse chromatin, and atypical mitosis. Cytology of CCSK is a spectrum with varying proportions of cord cells, septal cells, and mucopolysaccharide substance. Anaplastic CCSK is liable to misdiagnosis as Wilms tumor (WT) with unfavourable histology. Presence of eccentric cytoplasm in cord cells and nuclear grooves are the key to differentiation from Wilms tumor, including anaplastic variants.

Fetal rhabdomyomatous nephroblastoma: diagnosis by fine-needle aspiration cytology--a case report

The present report describes the case of a 21-mo-old boy with a fetal rhabdomyomatous nephroblastoma (FRN) diagnosed by fine-needle aspiration cytology (FNAC). The smears contained numerous isolated or clustered, deeply eosinophilic, thin, elongated rhabdomyoblasts with oval nuclei. Some of these cells presented cross-striations. Peculiar clusters of small, deeply eosinophilic, round cells with and without rounded nuclei in a mosaic pattern were interpreted as representing transversally oriented rhabdomyoblasts. Fetal rhabdomyoblasts were by far the predominant type of cell. Histology of the surgical specimen proved 90% of the mass to be constituted of fetal rhadomyomatous tissue. Adequate recognition of FRN is useful for the planning of treatment.

Cytomorphology of some uncommon tumors of childhood and adolescence

With the advent of newer adjuvant chemotherapeutic regimes resulting in dramatic improvement in survival, it is mandatory to obtain quick correct diagnosis, which is provided by fine needle aspiration cytology (FNAC). Cytology of childhood tumors was studied to find any distinguishing features, which would help in arriving at a diagnosis. Cytomorphology of 386 childhood and adolescent (0-19 years) tumors diagnosed between 1984 and 1993 were studied. Lipoma was the commonest benign tumor in 0-14 years age group. Fibroadenoma of the breast was the common benign tumor in adolescent (10-19 yrs) girls and pleomorphic adenoma in adolescent (15-19 yrs) boys. Wilms' tumor was the most frequent solid malignant tumor in preschool children and Hodgkin lymphoma, mixed cellularity in the school going age (5-19 yrs). Malignant tumors were more frequent (199). In addition, some rare malignancies like hepatoblastoma, meningioma, ganglioneuroblastoma, adrenocortical carcinoma, clear cell sarcoma kidney and malignant histiocytosis were diagnosed. The cytological features and the differential diagnoses are discussed. It is possible to diagnose these uncommon tumors if particular attention is paid to the distinguishing cytomorphological features in correlation with clinicoradiological findings and cytochemistry.

Unresectable stage IV nephroblastoma: a potential indication for fine-needle aspiration biopsy in children

In the United States, the initial morphologic diagnosis of nephroblastoma is usually determined on a nephrectomy specimen prior to the initiation of any additional therapy. Such an approach, however, is not appropriate in all children; we believe that fine-needle aspiration biopsies (FNAB) should be the initial diagnostic procedure in a minority of patients with suspected Wilms' tumor. One such group of patients is those who present with stage IV disease, especially when it is considered unresectable. Herein we present two children with advanced Wilms' tumor to support our contention. The initial microscopic diagnosis in each was made by FNAB. Following chemotherapy, predominantly necrotic Wilms' tumors were excised. Both patients are alive with no evidence of residual disease or untoward affects from the aspiration procedure.

Cystic nephroma: cytologic findings in fine-needle aspiration cytology

This report presents the fine-needle aspiration cytology (FNAC) findings of a multicystic renal tumor found in a 3-year-old child. The smears contained benign epithelial cells isolated or arranged in sheets of uniform cells strongly suggesting the lining of the cysts. The combination of the imaging data with the FNAC findings favoured the diagnosis of cystic nephroma (CN), a benign renal tumor that is cured by surgery. Surgical pathology confirmed the diagnosis. CN should be added to the list of tumors of the kidney in infancy that appear to be diagnosable by FNAC/biopsy.