Clinical, pathological, and immunohistochemical features of adenomyoma in the ampulla of vater.

BACKGROUND/AIMS: Ampullary adenomyoma is a benign lesion whose malignant potential has yet to be confirmed. Despite its benign nature, adenomyoma is frequently misdiagnosed as a carcinoma or adenoma and is overtreated by extensive surgery. This study was performed to analyze the clinical, pathological, and immunohistochemical features of adenomyomas in the ampulla of Vater.

METHODS

Nine cases of adenomyoma in the ampulla of Vater, diagnosed in Chungbuk National University Hospital between 2008 and 2011, were enrolled in this study. We reviewed the clinical data on the symptoms, laboratory data, and radiologic findings of the abdominal computed tomography and endoscopic retrograde cholangiopancreatography. For pathological analysis, all the slides were reviewed by one pathologist, and immunohistochemical stainings with antibodies against cytokeratin 7 (CK7), cytokeratin 20 (CK20), α-smooth muscle actin (α-SMA), and Ki-67 antigen were performed.

RESULTS

All the cases were CK7 positive and CK20 negative. A strong cytoplasmic expression of α-SMA was confirmed in all cases. The Ki-67 index was less than 1% in eight cases and 5% in one case. Four cases underwent endoscopic papillectomy, and one case received surgical ampullectomy during colorectal cancer surgery. Five cases that underwent endoscopic or surgical treatment remained symptom-free for three years. Four cases that were closely observed with repeated endoscopic examinations exhibited no interval changes in the papillary lesions.

CONCLUSIONS

Endoscopic biopsy and immunohistochemistry can aid in the diagnosis of ampullary adenomyomas. Endoscopic papillectomy or surgical ampullectomy is adequate for the treatment of symptomatic ampullary adenomyomas.