Fine-needle aspiration of pancreatic serous cystadenoma

Cytologic features and diagnostic pitfalls

Authors

  • Pochi Huang M.D.,

    1. Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas
    Current affiliation:
    1. Department of Pathology, Taichung Hospital Department of Health, The Executive Yuan, and the Central Taiwan University of Science and Technology, Taichung, Taiwan, Republic of China
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  • Gregg Staerkel M.D.,

    1. Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Nour Sneige M.D.,

    1. Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Yun Gong M.D.

    Corresponding author
    1. Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas
    • Department of Pathology, Unit 53, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
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    • Fax: (713) 794-5664


Abstract

BACKGROUND

The preoperative diagnosis of pancreatic serous cystadenoma (SCA) is important because as a typically benign tumor it can be treated expectantly, whereas many other cystic tumors require excision. This study examines the cytology, clinical and radiologic features, diagnostic accuracy of fine-needle aspiration (FNA), and potential pitfalls associated with this rare tumor.

METHODS

Cytomorphologic features were retrospectively reviewed from 28 FNAs of SCA from 21 patients. FNA biopsies were guided by percutaneous computed tomographic or ultrasonographic imaging in 10 cases and by endoscopic ultrasonographic imaging in 18 cases. Corresponding histology (14 tumors) and clinical/imaging findings were also evaluated.

RESULTS

Patients typically presented with upper abdominal discomfort or asymptomatically. Radiologically, a well-demarcated, multiloculated cystic mass involving the pancreatic head or uncinate process was common. Aspirates were sparsely cellular against a clean or granular, proteinaceous background. Tumor cells formed loose clusters or monolayered sheets composed of cuboidal cells with indistinct cell borders and granular or clear cytoplasm that was often stripped from the nucleus. Nuclei were small, round, with fine chromatin and indistinct nucleoli and devoid of mitotic activity. Seven (25%) of the aspirates were initially classified as “consistent with SCA,” 6 (21%) as “no malignant cells,” 3 (11%) as “nondiagnostic specimen,” 3 (11%) as “suspicious for malignancy,” 3 (11%) as “rare atypical cells,” and 6 (21%) as “probably or consistent with mucinous cystic neoplasm.” Features causing diagnostic difficulty were scant cellularity, papillary groups, nuclear atypia, and columnar cells mimicking those of mucinous neoplasms. Gastrointestinal (GI) epithelium and mucin also caused confusion. The detection of intracytoplasmic glycogen (3 of 6 cases) and cyst fluid analysis (2 of 2 cases) showing low viscosity and low or undetectable levels of carcinoembryonic antigen, CA 19.9, and amylase enhanced diagnostic confidence.

CONCLUSIONS

Diagnosing SCA by FNA is challenging. Familiarity with its morphologic spectrum, use of ancillary studies, and correlation with clinical/radiologic findings greatly improves diagnostic accuracy. Contaminating GI epithelium and mucin should be distinguished from components of a mucinous neoplasm. Cancer (Cancer Cytopathol) 2006. © 2006 American Cancer Society.

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