Ultrasound guided fine needle aspiration cytology in the diagnosis of retroperitoneal masses: A study of 85 cases

BACKGROUND: The diagnosis of retroperitoneal lesions is one of the most difficult areas in surgical pathology. The retroperitoneal space allows both primary and metastatic tumors to grow silently before the appearance of clinical signs and symptoms. Fine needle aspiration cytology has shown promising role in establishing the diagnosis in this region. OBJECTIVES: This study was undertaken to evaluate the reliability of ultrasonography (USG)-guided fine needle aspiration cytology (FNAC) in distinguishing between benign and malignant lesions in the retroperitoneum, and to correlate the diagnosis by cytology of retroperitoneal masses with the results obtained by histology. MATERIALS AND METHODS: The study was carried out on 85 patients presenting over the last five years with retroperitoneal masses on ultrasound. RESULTS: Out of 85 cases, 32 were of kidney, 27 of lymph nodes, 24 of retroperitoneal soft tissues, and two were of the adrenals. Malignant lesions (47) were more common than nonmalignant lesions (38). In the kidney, the maximum number of cases were of renal cell carcinoma (12-38%), followed by Wilm's tumor (6-19%), pyonephrosis (5-16%), renal cyst (4), angiomyolipoma (2), cortical pseudotumor (2), and tuberculosis (1). Out of 27 cases of retroperitoneal lymphadenopathy, 12 cases (44%) were of metastatic carcinoma followed by non-Hodgkin's lymphoma (8-30%), tuberculosis (6-22%), and Hodgkin's lymphoma (1). The two cases of the adrenals were of angiomyolipoma and metastatic carcinoma. Among the 24 soft tissue tumors in the study, seven (29%) were malignant and 17 (71%) were benign (lipoma being the most common benign neoplasm). Results from histopathological investigations were available in 47 cases, out of which 45 were consistent with the FNAC-based diagnoses. Two cases for which the histopathological results were inconsistent with the FNAC diagnoses, were of renal cell carcinoma, which had been diagnosed as renal cysts on cytology. CONCLUSIONS: USG-guided FNAC is an inexpensive, rapid, safe, and accurate procedure for the diagnosis of retroperitoneal masses.