Fine-needle aspiration biopsy of clear-cell sarcoma of the kidney: light and electron microscopic features

Clear cell sarcoma, cellular mesoblastic nephroma and metanephric adenoma: cytological features and differential diagnosis with Wilms tumour

Wilms' Tumour (WT) is the most common kidney tumour in childhood, this fact and the embryonic complexity of WT create, whenever one of its three classical components predominates in cytologic smears, difficulties in the differential diagnoses with other less common entities. In the present study, we review the cytological and immunohistochemical characteristics of three children renal tumours, a Clear Cell Sarcoma of the Kidney (CCSK-case1), a Cellular Mesoblastic Nephroma (CMN-case2) and a Metanephric Adenoma (MA-case3) and compare them, for differential diagnostic purposes, with smears of blastematous, mesenchymal and epithelial predominant WTs, previously diagnosed in our Department. In all cases a mass was detected in the abdomen (2 and 8 year old children-cases 1 and 3, respectively), and pre-birth in case 2 (the tumour was detected during pregnancy). Fine needle biopsy was performed followed by routine cytologic examination. The presence of moderate amount of blue pale cytoplasm in neoplastic cells (case1), the presence of tightly cohesive, bland, spindle tumour cells (case2) and the identification of small, well differentiated epithelial tubules with psammoma bodies in case 3, were the main morphologic characteristics that we think represent the most important elements for distinguishing our cases from a WT. Immunoreactivity was only helpful in case 1 as we found a characteristic dot-like pattern positivity for vimentin, in the absence of immunoreactivity for the other markers that are usually positive in WT. Summing up, these three cases demonstrate that cytopathologists should be aware of the occurrence of uncommon renal neoplasms in childhood and should be acquainted with their characteristics, in order to avoid false diagnoses.

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.

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.

FNA biopsy of small round cell tumors of childhood: cytomorphologic features and the role of ancillary studies

Pediatric tumors which are conventionally considered to be small round cell tumors (SRCTs) include the prototypical neuroblastoma as well as rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), malignant lymphoma, and primitive neuroectodermal tumor (PNET). Other malignancies may be considered in the differential diagnosis such as small-cell osteogenic sarcoma, undifferentiated (anaplastic) hepatoblastoma, granulocytic sarcoma, blastemal type Wilms' tumor, and desmoplastic small-cell tumor of the peritoneum. The cytomorphologic features of conventional SRCTs is presented as well as the utility of ancillary studies performed on the aspirated material in making a specific and correct diagnosis. The role of the immediate cytologic assessment of the aspirate is stress, since this is a critical step in formulating an initial diagnostic impression that should prompt the need for additional material for pertinent ancillary studies. Although challenging, FNA cytology of SRCTs of childhood can be diagnostic in the majority of cases, allowing specific therapy to be given to patients with unresectable SRCTs without a tissue biopsy as well as documenting recurrent and/or metastatic disease.

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.

Cytologic characteristics of congenital mesoblastic nephroma in fine-needle aspiration cytology: a case report

The cytologic features of congenital mesoblastic nephroma (CMN) as recognized in smears of fine-needle aspirated cytology (FNAC) are reported. These included spindle- and tadpole-shaped cells with round to oval nuclei having small nucleoli and a smooth contour. The cytoplasm of these cells was dense and homogeneously stained. The background was composed of mucoid fibrillar material. The findings appear to be different from other types of renal tumors in infancy and specific enough for this tumor to allow diagnosis by FNAC.

The utility of ancillary studies in pediatric FNA cytology

We evaluated the diagnostic contribution of adjunct studies performed on aspirated material in the work-up of pediatric fine-needle aspiration (FNA) biopsies. Ancillary studies were performed on 54 of 136 (39.7%) pediatric FNA biopsies during a 5-year period. In 23 (16.9%) cases, immunocytochemical (ICC) studies, consisting of immunoperoxidase staining of direct smears and/or cell blocks or flow cytometric immunophenotyping, were performed. The studies were adequate in 14 cases (60.9%), suboptimal in five cases (21.7%), and inadequate in four cases (17.4%). Of the adequate and suboptimal cases, the ICC data helped to narrow the differential diagnosis or classify the disease process in eight cases (42.1%), confirmed cytologic impression in nine cases (47.4%), and gave contradictory results in two cases (10.5%). Adequate material for electron microscopy (EM) was obtained in 14/19 cases (73.7%). Ultrastructural studies were diagnostic, or helped classify the disease process in five cases (35.7%), confirmed the cytologic impression in four cases (28.6%), helped exclude diagnostic considerations in three cases (21.4%), and were judged to be non-contributory in two cases (14.3%). Cytogenetic studies revealed six of seven cases (all neoplasms) to have abnormal karyotypes. Special stains for organisms performed on smears from 25 cases including Ziehl-Neelsen, Gomori methenamine silver (GMS), Gram, and Warthin-Starry (WS) were negative except for 1/16 GMS and 4/9 Gram stains. In summary, we found that with appropriate case selection, ancillary studies performed on aspirated material can provide useful information in pediatric FNA cytology.

Malignant rhabdoid tumor of the kidney presenting as intraocular metastasis

A newborn infant presented with intraocular tumor that was clinically diagnosed as retinoblastoma and treated by exenteration of the globe. Within a few weeks however, a large abdominal mass was noted, which was found to involve the left kidney and right lobe of liver. Pathologic evaluation of the intraocular mass as well as fine-needle aspiration biopsy of the abdominal mass revealed features of malignant rhabdoid tumor. To our knowledge this is the first case of malignant rhabdoid tumor of the kidney with such an unusual clinical presentation.

Fine-needle aspiration biopsy diagnosis of malignant rhabdoid tumor of the kidney

A series of six fine-needle aspiration biopsies from three patients with malignant rhabdoid tumor of the kidney is reviewed. The smears revealed round, polygonal, and irregularly shaped cells with large nuclei and prominent nucleoli. Some of the tumor cells contained light pink to purple cytoplasmic inclusions that correlated with the eosinophilic inclusions seen in histopathologic sections and filamentous cytoplasmic aggregates noted on ultrastructural examination. Diagnosis of malignant rhabdoid tumor of the kidney may be suggested from aspiration biopsy smears; however, further confirmation of the diagnosis by histologic or ultrastructural examination is desirable.