Nodular fasciitis a correlative cytologic and histologic study of 13 cases.

Nodular fasciitis, the most common pseudosarcomatous proliferative lesion of the soft tissues, is well defined histologically but not cytomorphologically. A histologic and cytologic study of 13 cases of nodular fasciitis is presented. Nodular fasciitis is characterized histologically by proliferating fibroblastlike cells that vary from thin, elongated and spindle shaped with elongated nuclei to plump with one or more large, oval nuclei. The appearance of nodular fasciitis in fine needle aspirations is characterized by the presence of tumor cells varying widely from spindle shaped with long cytoplasmic processes to more plump and cytoplasmatic with one or more nuclei with nucleoli. An attempt to correlate the histologic and cytologic appearances is made. It is stressed that all the cells in nodular fasciitis lack histologic and cytologic signs of malignancy. The differential diagnosis is discussed. The cytomorphology of nodular fasciitis is fairly characteristic, making it possible to recognize these lesions in fine needle aspirates.