Combined use of EUS-guided FNA and immunocytochemical stains disclosed metastatic and unusual diseases in the evaluation of mediastinal lymphadenopathy of unknow etiology

ABSTRACT

Mediastinal lymphadenopathy [ML] is a cause for concern, especially in patients with previous malignancy. We report our experience with the use of endoscopic ultrasound-guided fine needle aspiration [EUS-FNA] with immunocytochemical stains in patients being evaluated for ML. Retrospective analysis of patients with ML of unknown origin who underwent EUS-FNA. On-site evaluation was performed by experienced cytologist, and special immunocytochemical stains were requested as indicated. A total of 116 patients were included, and a total of 136 mediastinal LN were sampled. Prior malignancy was present in 45%. The most common site of examined lymph node [LN] were subcarinal [76%, 103 LN]. The median long and short axis diameters were 28 mm and 13 mm, respectively. FNA was read on-site as malignant, 21 [16%]; benign, 100 [76.9%]; suspicious, six [4%]; atypical, 3 [2%]; and inadequate sample, six [4%]. Sixty-four LN were deferred for additional studies; 22 for immunocytochemical and 26 for Gimesa [GMS] stain and 21 for flow cytometry. Final FNA read was malignant in 28 [21%], benign in 103 [76%], suspicious in three [2%], and atypical in two [1%]. Metastatic malignancies disclosed included Hodgkin's and Non-Hodgkin's lymphoma, melanoma, hepatoma, breast, lung, colon, renal, endometrial, Fallopian tube, and unknown carcinoma. The sensitivity, specificity, and accuracy of the final FNA read to predict malignancy were 100%. EUS-guided FNA with additional ancillary studies is useful in disclosing metastatic ML from a variety of neoplasms. Due to its safety and accuracy profile, it should be considered the test of choice in evaluating abnormal ML in appropriately selected patients