Diagnostic value of needle aspiration cytology (NAC) in the assessment of palpable inguinal lymph nodes: a study of 210 cases.

The aim of this study was to evaluate the diagnostic value of needle aspiration cytology (NAC) in the assessment of palpable inguinal lymph nodes, which were analyzed in 210 cases. NAC in all the cases were performed by the conventional aspiration method and cytologic examination was done on site after staining smears with the Papanicolaou method. In addition, Diff-Quik-stained air-dried smears, Papanicolaou-stained fixed smears, and filter preparations from needle washings and hematoxylin-eosin-stained sections of cell blocks were studied. The NAC diagnosis was supported by examining cell blocks in 92/210 cases which showed a reliable histologic architecture; further support was also obtained with a tissue biopsy in 9/12 cases of inflammatory lesions, 7/7 cases with a suspicious diagnosis, 20/26 cases of melanomas, 15/15 cases of lymphomas, and/or a comparison with the primary tumor in other cases of metastatic tumors. Additionally, immunoperoxidase and/or histochemical stains were done. Twelve cases were diagnosed as inflammatory lesions and 88 cases were regarded as negative (normal cellular elements n = 40; reactive elements n = 48). In 58 cases a variety of metastatic tumors were diagnosed (melanoma n = 26; others n = 32) and in 15 cases a diagnosis of lymphoma was made. Seven cases were diagnosed as suspicious of malignancy and 30 cases were unsatisfactory due to scanty/acellular samples (despite 2-3 repeat samplings). However, in five of these malignant tumors were later found on a biopsy which was done due to a persistent and continued enlargement of lymph node(s). The sensitivity was 91.7%, specificity 98.2%, positive predictive value (PPV) 97.7.%, and negative predictive value (NPV) was 95.45%. Based on our study we feel that NAC as a first line of investigation is not only useful in the diagnosis of lesions in inguinal lymph nodes, but can also help in deciding on an appropriate management. Also, histologic architecture from cell blocks can be correlated with cytology and such material can be used for histochemical and immunomarker studies.