title: Cytodiagnostic aspects of lung adenocarcinoma manifesting with micropapillary pattern in sputum: a case report of potential diagnostic pitfall.
abstract: The micropapillary pattern of lung adenocarcinoma was discussed in the 2004 World Health Organization classification and is now proposed as a distinct pattern in the new International Multidisciplinary Classification of Lung Adenocarcinoma Guidelines. The micropapillary pattern is histologically characterized by papillary tufts lacking a central fibrovascular core and is associated with an unfavorable prognosis. Herein, we report the cytological features of lung adenocarcinoma with the micropapillary pattern in a sputum specimen. A 75-year-old woman presented with a productive cough, blood-tinged sputum, and some symptoms of upper respiratory tract infection. The initial impressions from her chest radiograph and computed tomography scan indicated pneumonia. However, the initial sputum cytology sample showed a few clusters of cells with abnormal three-dimensional structure, interpreted as adenocarcinoma. These cells were small and had minimal cytologic atypia, demonstrating a potential diagnostic pitfall. The following biopsy confirmed lung adenocarcinoma with the micropapillary pattern. Here, we describe this case and discuss the differential diagnosis of pulmonary entities exhibiting similar morphologies.
authors.affiliation: Department of Anatomic Pathology, Buddhist Dalin Tzu Chi General Hospital, Chiayi, Taiwan; Department of Pathology, Da Chien General Hospital, Miaoli, Taiwan.
authors.forename: Nien-Yi
authors.initials: NY
authors.lastname: Chang
authors.forename: John
authors.initials: J
authors.lastname: Wang
authors.forename: Cheng-Ching
authors.initials: CC
authors.lastname: Lin
authors.forename: Su-Wey
authors.initials: SW
authors.lastname: Chen
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology*; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology*; D013183:Sputum / Q000166:cytology*
keywords: cytology; lung adenocarcinoma; micropapillary; sputum