title: Well-differentiated fetal adenocarcinoma of the lung mimicking adenoid cystic carcinoma on fine needle aspiration: A case report.
abstract: Well-differentiated fetal adenocarcinoma (WDFA) of the lung is a rare variant of adenocarcinoma with an unusual morphology. Although the histologic features of this rare neoplasm have been well established, there is a deficit in the literature with regards to its discrete cytomorphologic features. We report the fine needle aspiration (FNA) findings of a case of this unusual malignancy in a 44-year-old man with an incidental lung nodule. FNA revealed three-dimensional clusters of epithelial cells with scant cytoplasm, hyperchromatic nuclei that are associated with an extracellular metachromatic matrix. The original cytology report was signed out as an epithelial neoplasm favor adenoid cystic carcinoma. Consequently, a wedge resection of the lung was done and the histologic diagnosis was WDFA of the lung. The findings of minimal nuclear atypia in association with focally abundant spheres of extracellular matrix can mimic adenoid cystic carcinoma. WDFA has good prognosis and therefore, pre-operative cytologic diagnosis is critical to clinical management. We present the cytomorphologic features of this neoplasm with particular emphasis on a potential diagnostic pitfall of this rare entity. Diagn. Cytopathol. 2016;44:917-920. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand.
authors.forename: Vilasinee
authors.initials: V
authors.lastname: Rerkpichaisuth
authors.affiliation: Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Collins
authors.affiliation: Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand.
authors.forename: Thiraphon
authors.initials: T
authors.lastname: Boonyaarunnate
authors.affiliation: Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland. sali@jhmi.edu.|Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland. sali@jhmi.edu.
authors.forename: Syed Z
authors.initials: SZ
authors.lastname: Ali
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D044963:Biopsy, Fine-Needle; D003528:Carcinoma, Adenoid Cystic / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male
keywords: adenoid cystic carcinoma; cytopathology; extracellular matrix; fetal adenocarcinoma; fine needle aspiration; hyaline globule; lung cytopathology