FINE-NEEDLE ASPIRATION CYTOLOGY OF A MEDIASTINAL GRANULAR-CELL TUMOR WITH HISTOLOGIC CONFIRMATION AND ANCILLARY STUDIES - A CASE-REPORT

BACKGROUND: Mediastinal granular cell tumors (GCT) are extraordinarily rare and have not been previously reported in the cytology literature . Fine needle aspiration (FNA) cytology of GCT resembles the cytologic features of several other lesions that are more common in the mediast inum. CASE: A middle-aged female with a recent onset of nonproductive cough and otherwise unremarkable medical history presented with a medi astinal mass. Imaging studies confirmed the presence of a large mass i n the superior, posterior mediastinum closely apposed to the apex of t he left lung. FNA revealed scattered large, polygonal to spindle cells with granular cytoplasm and indistinct cell borders. The cytologic di fferential diagnosis included a benign neural tumor with granular cell features versus GCT. Histologic examination of the surgically resecte d mass along with supportive immunohistochemical and electron microsco pic studies confirmed GCT. CONCLUSION:This is the first reported case of FNA cytology of a mediastinal GCT. A reliable diagnosis can be made with aspirated material from these lesions based upon the characteris tic cytologic, immunocytochemical and ultrastructural features of the tumors.