The cytological diagnosis of paediatric renal tumours

Abstract

Fine needle aspiration cytology (FNAC) is used for preoperative diagnosis of paediatric renal tumours, especially in centres where preoperative chemotherapy is advocated in Wilms' tumour. This review focuses on salient cytological features in specific paediatric renal tumours, the approach to resolving a differential diagnosis and the role of ancillary methods in diagnosis of paediatric renal tumours. Crucial differential diagnoses include distinguishing: Wilms' tumour from benign tumours in the kidney like multicystic nephroma or congenital mesoblastic nephroma; aggressive non-Wilms' tumours of kidney like rhabdoid tumour of kidney; and Wilms' tumour from other paediatric round cell sarcomas like neuroblastoma, non-Hodgkin lymphoma etc. An approach based on classifying smears according to their cellular patterns as triphasic, round cell, spindle cell or epithelioid cell type assists in classifying paediatric renal tumours on cytology. Immunocytochemistry for WT1, cytokeratin, synaptophysin, leucocyte common antigen and MIC2 will aid in evaluating round cell tumours in the renal region, while WT1, bcl2, vimentin and desmin will be useful for spindle cell tumours in that region. Extra material can also be evaluated for demonstration of specific cytogenetic abnormalities in these tumours. A checklist of common tumours in a particular age group, relevant clinical information, awareness of distinctive and overlapping cytological features, and appropriate use of immunocytochemistry with cytogenetics go a long way in ensuring an accurate cytological diagnosis. Used judiciously, FNAC is as effective a tool as a core biopsy for preoperative diagnosis of paediatric renal tumours, and with experience a 92% accuracy rate can be achieved.Fine needle aspiration cytology (FNAC) in paediatric renal masses is performed for diagnosis of tumours in patients with advanced disease before instituting preoperative chemotherapy and for documentation of contralateral disease/metastases/recurrence.

Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines

“…When required, both FNA and CNB techniques provide adequate samples. The cellularity was judged satisfactory in 82% to 85% of our cases, in agreement with the literature (i.e., 76% to 93% for FNA and 80% to 95% for CNB) . However, our data confirm a significantly higher diagnostic accuracy of CNB, as previously reported .…”

“…Cell suspensions from FNA can be used for complementary genetic analyses. In case of poor quality material (highly necrotic tumors), cytocentrifugation of cell suspensions allows the preparation of paraffin‐embedded cell blocks, allowing subsequent immunohistochemical studies . Finally, FNA also constitutes an alternative to CNB in cases with severe clotting disorders.…”

Cytologic Features of SMARCA4-Deficient Thoracic Sarcoma: A Case Report and Comparison with Other SWI/SNF Complex-Deficient Tumors

“…The amount of cytoplasm has been variably described, but is always abundant in proximal-type epithelioid sarcomas but less abundant or scant in MRTs and SCCOHTs. Moreover, rhabdoid cells or cells with perinuclear hyaline inclusions have been frequently noted in these 3 neoplasms [8, 9, 11, 12, 14-16, 18, 20]. Perinuclear cytoplasmic densities (denser in the inner area than in the periphery) have also been noted [9, 15].…”

Review of renal cell carcinoma with rhabdoid features with focus on clinical and pathobiological aspects

“…Malignant lymphomas most commonly completely lack cell cohesion and infiltrating sclerosis, and in most cases display limited amounts of cytoplasm and react positively to leukocyte common antigen [1]. Wilms' tumor may exhibit rhabdomyoblastic differentiation, but the age of patients, the presence of blastemal cells and positivity for myogenic markers are helpful diagnostic clues [1,40]. In the distinction from CMN, the age of patients within 3 years after birth and the identification of ETV6-NTRK3 fusion are important [1,41].…”