title: Pulmonary tumorlet: a case report of a diagnostic pitfall in cytology.
abstract: BACKGROUND
  Pulmonary tumorlets are usually an incidental pathologic curiosity of no clinical importance, but may be mistaken for epithelial and nonepithelial neoplasms. Fine needle aspiration (FNA) of this cell proliferation has rarely been reported. We describe a pulmonary tumorlet associated with bronchocentric granulomatosis presenting as a tumorous consolidation on chest radiograph.
  
  
  METHODS
  In a hitherto healthy 70-year-old man admitted for acute respiratory infection, a solid consolidation was found on chest radiograph. Medical history was uneventful except right-sided pleurisy in 1949. Computed tomography-guided FNA sample was composed of loose clusters of small columnar cells with cyanophilic cytoplasm and centrally located round to oval nuclei. With a tentative diagnosis of well-differentiated adenocarcinoma, lumpectomy was performed. Intraoperative cytology demonstrated lymphocytes, epithelioid cells, giant cells of Langerhans type and clusters of columnar cells. Definitive histologic examination confirmed the intraoperative diagnosis of necrotizing granulomatosis and tumorlet. Neuroendocrine origin of the cells was confirmed by immunocytochemical and immunohistochemical studies resulting in strong reactivity of the cells to synaptophysin, NSE, chromogranin A and N-Cam.
  
  
  CONCLUSIONS
  Knowledge of the cytomorphologic presentation of tumorlets in FNA and consideration of the appropriate differential diagnoses combined with ancillary studies might have prevented lung resection.
authors.affiliation: Second Medical Department, Otto Wagner Spital, Vienna, Austria. christine.armbruster@gmx.at
authors.forename: Christine
authors.initials: C
authors.lastname: Armbruster
authors.forename: Klaus
authors.initials: K
authors.lastname: Bernhardt
authors.forename: Ulrike
authors.initials: U
authors.lastname: Setinek
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D000368:Aged; D044963:Biopsy, Fine-Needle; D001982:Bronchial Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D003951:Diagnostic Errors / Q000517:prevention & control*; D015769:Granuloma, Respiratory Tract / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008297:Male; D009336:Necrosis; D011013:Pneumonectomy; D011859:Radiography; D019564:Unnecessary Procedures