title: Appearance of absorbable gelatin compressed sponge on early post-thyroidectomy neck sonography: a mimic of locally recurrent or residual thyroid carcinoma.
abstract: OBJECTIVE
  Absorbable gelatin compressed sponge (Gelfoam; Pfizer Inc, New York, NY), a biodegradable agent prepared from purified porcine skin gelatin, is frequently used for intraoperative hemostasis. Its appearance on sonography may mimic tumor or residual thyroid when placed in the resection bed after thyroidectomy. The purpose of this study was to describe the appearance of Gelfoam on early post-thyroidectomy sonography so that an erroneous diagnosis of locally recurrent or residual tumor can be avoided.
  
  
  METHODS
  We reviewed the early postoperative sonographic examinations of 6 patients after thyroidectomy in which Gelfoam was used for hemostasis. Screening cervical sonography was performed to identify possible lateral compartment adenopathy before completion of thyroidectomy or ablation. Sonographic examinations were performed up to 50 days after resection. Surgical reports confirmed the use of Gelfoam in each patient.
  
  
  RESULTS
  In all cases, uniform elongated echogenicity was shown within the lobectomy bed. In 1 patient, sonographically guided fine-needle aspiration of lobectomy bed echogenicity yielded scant red blood cells, multinucleated giant cells, and macrophages. Follow-up sonography performed in 1 patient 14 months after thyroidectomy confirmed complete Gelfoam absorption.
  
  
  CONCLUSIONS
  Gelfoam may mimic residual or recurrent thyroid carcinoma on early surveillance sonography performed after thyroidectomy. Recognition of its characteristic appearance should prompt a search for an appropriate surgical history and, when placed in the appropriate clinical context, should prevent an errant diagnosis of tumor.
authors.affiliation: Department of Radiology, University of Pittsburgh School of Medicine, 200 Lothrop St, Pittsburgh, Pennsylvania15213, USA. tublinme@upmc.edu
authors.forename: Mitchell E
authors.initials: ME
authors.lastname: Tublin
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Alexander
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Ogilvie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005189:False Positive Reactions; D005260:Female; D005547:Foreign Bodies / Q000000981:diagnostic imaging* / Q000209:etiology; D005781:Gelatin Sponge, Absorbable / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D011182:Postoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome; D014463:Ultrasonography