FNA cytology of postoperative pseudotumoral lesions induced by oxidized cellulose hemostatic agents

Abstract

Background: The use of topically applied hemostatic substances during surgery has become a common practice. In some cases, the material is not absorbed or induces a granulomatous reaction resulting in a pseudotumoral lesion. With imaging studies, it is not possible to differentiate this from a tumor recurrence or abscess. This study describes the authors' cytologic experience with a large series of pseudotumoral lesions induced by oxidized cellulose, one of the most commonly used hemostatic agents. Almost no cytologic descriptions are available in the medical literature. Methods: Sixteen patients were evaluated, and the most common sites of fine-needle aspiration (FNA) were the mediastinum and thyroid surgical bed. Other locations were the axilla, neck, vulva, liver, and retroperitoneum. All these lesions appeared after surgical procedures in which oxidized cellulose was used as a topical hemostatic agent. The interval time between surgery and FNA varied from 4 to 46 months with a mean of 15 months. Results: Cytology samples showed very similar findings. In all cases, foreign-body material with a variable granulomatous reaction was present. Oxidized cellulose was seen as laminated inorganic fragments and most often showed an elongated, quadrangular appearance. Amorphous, ill-defined fragments as well as a dense proteinaceous background with phagocytic cells were also present. Conclusions: The current study demonstrates that FNA cytology is a very useful method for the detection of pseudotumoral lesions induced by hemostatic agents. Pathologists must be familiarized with this finding because cytology permits easy differentiation from tumor recurrence.