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Retroplasia of bronchial columnar cells mimicking intranuclear viral inclusions.

On cytologic preparations a variety of degenerative findings, which may be called retroplasia, have been recognized.1,2 Recently we encountered a case in which bronchial columnar cells in sputum showed retroplasia similar to intranuclear inclusions, suggestive of viral infection. To the best of our knowledge, such a finding in sputum has not been reported in the English-language literature. Herein we describe the cytologic findings and discuss the diagnostic pitfalls. The patient was a 48-year-old male with past history of duodenal ulcer. He had a history of smoking 40–50 cigarettes per day for 27 years. He noticed hemosputum two weeks earlier. Chest roentgenography did not reveal any abnormal shadows. Bronchoscopy demonstrated a nonelevated, whitish lesion in the left B3 bronchus. A biopsy of the lesion and cytologic examination of sputum after the procedure was performed. All laboratory data were within normal limits. The cytology specimen revealed ciliated columnar cells, squamous metaplastic cells, neutrophils and alveolar macrophages. Several ciliated columnar cells showed large intranuclear inclusions with a distinct halo (Figure 1). The inclusions were homogeneous and basophilic. The nuclear membrane was markedly thickened. Inclusions were also observed in a few squamous cells. There were no multinucleated cells, ciliocytophthoria or reactive pneumocytes. We peeled the ciliated columnar cells with the inclusions from the preparation using the peel-and-stick method for immunocytochemical examination3 and open-face embedding technique for transmission electron microscopy.4 Immunocytochemically, the inclusions were negative for anti–herpes simplex virus type 1 (B114, 1 :2,000, Dakopatts, Copenhagen, Denmark) and type 2 (B116, 1 :2,000, Dakopatts) and anticytomegalovirus (DDG9 and CH2, 1:20, Dako, Glostrup, Denmark). Ultrastructually, the inclusions were composed of a Acta Cytologica