SPINDLE-CELL LESIONS OF THE MEDIASTINUM - DIAGNOSIS BY FINE-NEEDLE ASPIRATION BIOPSY

Spindle cells seen in fine-needle aspiration biopsy (FNAB) of the medi astinal lesions can be a component of a wide variety of benign and mal ignant conditions. Few of these conditions, however are described in t he FNA cytopathology literature. This review discusses the cytopatholo gic features, differential diagnoses, and potential pitfalls of a vari ety of lesions with a significant component of spindle cells encounter ed in mediastinal FNAB. The cytopathology files from four institutions were searched for cases of mediastinal FNAB containing a spindle-cell component that was a key or predominant cytologic feature of the diag nostic specimen. The cytomorphologic features of these cases were anal yzed, and their differential features are discussed. Of 196 mediastina l FNABs, 22 (11%) were lesions with significant spindle-cell component : granulornatous inflammation (four); benign nerve sheath tumor (four) ; thymic cyst (two); spindle-cell thymoma (two); large-cell non-Hodgki n's lymphoma with sclerosis (two); nodular sclerosing Hodgkin's diseas e (two); liposarcoma (two); spindle-cell squamous carcinoma possibly a rising in a teratoma (one); unspecified high-grade sarcoma (one); spin dle-cell malignant melanoma (one); and nonspecific fibrous tissue (one ). The cytologic features of each lesion were analyzed as an aid for a ccurate classification. These findings were correlated with radiologic and clinical information when available. The value of ancillary studi es performed on aspirated material in selected cases was also reviewed FNA of mediastinal lesions with significant spindle-cell morphology r epresents an infrequent and heterogeneous group of entities that may p ose significant diagnostic challenges. This review presents the salien t cytopathologic features of various spindle-cell lesions of the media stinum with particular emphasis on differential diagnosis and pitfalls . The pathologist must use caution when interpreting these lesions and ancillary studies may be of significant value in selected cases. (C) 1997 Wiley-Liss, Inc.