Retroperitoneal Tumor: A Silent Trespasser – Role of Image-Guided Fine-Needle Aspiration Cytology with Histopathological Correlation in Early Diagnosis

Abstract

Objective: Retroperitoneal lesions present a great diagnostic challenge. Here we analyze the spectrum of retroperitoneal lesions and the utility of cytohistopathological correlation in early diagnosis. Study Design: This 7-year study was undertaken in 338 patients with a retroperitoneal mass (kidney/adrenal/ pancreas/retroperitoneal lymph node, or soft tissue origin). In a prospective analysis, 81 patients underwent image-guided fine-needle aspiration cytology (FNAC) and 70 of the 81 underwent Tru-cut biopsy/histopathological evaluation. Clinical, radiological, and pathological details of 257 patients were retrieved from institutional records for retrospective analysis. A total of 119 patients, i.e., 70 in the prospective analysis and 49 in the retrospective analysis, had cytohistopathological correlation. Results: Of the 338 cases, 88.4% were malignant (n = 274), 2.6% were benign (n = 8), 9% were nonneoplastic (n = 28), and 9% were inadequate (n = 28). Most were renal in origin (n = 106; 34.2%), followed by retroperitoneal soft tissue (n = 96; 31%). The most common nonneoplastic lesion was tubercular lymphadenitis (42.85%) and the most common benign lesion was paraganglioma (42.85%). The most common malignancy was renal cell carcinoma (21.16%), followed by Wilms’ tumor (13.86%). In infancy and early childhood, Wilms’ tumor, neuroblastoma, and germ cell tumor were the most common malignancies, while in middle age it was renal cell carcinoma, followed by pancreatic adenocarcinoma, and in the elderly age group it was metastatic carcinoma. Most malignancies were noted in the 5th to 6th decades. The overall sensitivity, specificity, and diagnostic accuracy of image-guided FNAC was 98.02, 72.22, and 94.12%, respectively. Conclusion: Image-guided FNAC is highly sensitive and specific for early diagnosis of an otherwise silent retroperitoneal mass. It saves patient from meticulous surgical procedures for diagnostic reasons and allows more rational planning of management. Knowledge of the distribution of tumors by age group helps to narrow down differential diagnoses.