Pulmonary mucinous adenocarcinoma (PMA) is the terminology recently proposed in the new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) International Multidisciplinary Classification of Lung Adenocarcinoma Guidelines for most tumors previously classified as mucinous bronchioloalveolar carcinomas (mBACs). PMA is histologically characterized by lepidic growth and at least some degree of invasive growth of goblet or columnar neoplastic cells with abundant intracytoplasmic mucin. We report here the cytologic features of PMA in a bronchial brushing specimen. The patient is an 84-year-old woman with a persistent dense consolidation in the right middle lobe of the lung found on non-contrast computed tomography (CT) scan. Bronchial brushing smears showed a monotonous population of columnar neoplastic cells forming "drunken honeycomb"-like cell clusters. The neoplastic cells displayed inconspicuous cytologic atypia. The concurrent transbronchial tissue biopsy and the resection specimen confirmed the diagnosis of PMA. Due to the bland nuclear features, the neoplastic cells in the bronchial brushing specimen were interpreted as benign at the time of the initial diagnosis, demonstrating a diagnostic pitfall of bronchial brushing cytology. A high index of suspicion is recommended when a lung lesion with "drunken honeycomb"-like cell clusters is encountered in bronchial brushing specimens. The review of the literature regarding the recently designated PMA is presented.

Plasmablastic lymphoma (PBL) is a rare subtype of diffuse large B cell lymphoma and commonly presents as an oral mass in HIV patients. Extraoral PBL has been reported, including one case of primary central nervous system PBL (PCNSPBL). The cytological features of PBL have been described, including cerebrospinal fluid (CSF) cytology findings for secondary CNS involvement by PBL. The etiology of PCNSPBL is still unknown. We report here the CSF cytology of a PCNSPBL, which shows a hypercellular specimen composed of markedly atypical, singly dispersed plasmacytoid cells with frequent abnormal mitoses and binucleation. The neoplastic cells are positive for CD138. Flow cytometry of the CSF specimen demonstrates a monoclonal neoplastic cell population, which is CD138 positive, kappa light chain positive, lambda light chain negative, and CD19 negative. Molecular analysis and immunohistochemical stains on a tissue biopsy confirmed the diagnosis and reveal concurrent infections with Epstein-Barr virus and human polyomavirus JC virus. Clinical and radiological correlations are reported, and the literature is reviewed. To the best of our knowledge, this is the first case report for CSF cytology of a PCNSPBL, demonstrating the utility of the cytological examination in the triage and diagnosis of this disease. Because of its dismal prognosis, it is critical for cytopathologists to be aware of the entity and recognize the neoplastic cells in CSF specimen. This report also emphasizes the importance of clinical and radiological correlation in the diagnosis of this lethal disease.