FINE-NEEDLE ASPIRATION OF GASTROINTESTINAL STROMAL TUMORS

Gastrointestinal stromal tumors are a group of neoplasms encompassing leiomyoma, leiomyosarcoma, and an epithelioid variant of leiomyosarcom a, as well as lesions expressing neural differentiation. These neoplas ms are rare and account for 1% of all gastrointestinal tumors. With in creasing frequency, fine-needle aspiration (FNA) has been used to diag nose intra-abdominal neoplasms before institution of definitive treatm ent. We encountered four patients with gastrointestinal stromal tumors diagnosed by FNA who ultimately underwent surgical excision of their tumors. The age of the patients ranged from 57 to 88 years. Smears fro m the aspirates were cellular and consisted of numerous small spindle cells distributed as cohesive fragments and individual cells. The disp ersed cell population appeared largely as stripped nuclei. Several nuc lei had perinuclear or paranuclear vacuoles, similar to the ''halos'' seen in sections. Cytologic evidence of malignancy (pleomorphism, nucl ear irregularity, mitoses) were not identified in smears. Correspondin g histologic sections demonstrated varying degrees of malignancy rangi ng from benign or low grade to frankly sarcomatous gastrointestinal st romal tumors. We conclude that the diagnosis of gastrointestinal strom al tumors can be made with a certain degree of confidence by using FNA findings. However, predictions about potential aggressiveness are bes t reserved for gross and histologic examination of the resected specim en.