Nine pulmonary aspiration syndrome cases of atypical clinical presentation, in which the final diagnosis was obtained by histological examinations

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While pulmonary aspiration syndrome (PAS) is primarily clinically diagnosed, atypical PAS cases can be misdiagnosed clinically and are more accurately diagnosed histologically. To elucidate clinicopathological features of these rare cases, we examined PAS cases determined by histological examination of transbronchial lung biopsy (TBLB) specimens. Of 6105 TBLB cases investigated from 1990 to 2007, 11 were diagnosed as PAS based on histology. Of these, we examined 9 records in detail, as the medical records for 2 cases were unavailable. Histopathological findings indicated 8 patients with aspiration pneumonia and 1 with diffuse aspiration bronchiolitis. However, the pre-bronchoscopy diagnoses included lung cancer, mycobacteriosis, organizing pneumonia, repetitive pneumonia, fungal infection, and interstitial pneumonia. PAS was not considered before TBLB. Only 4 of the 9 patients developed subjective symptoms including fever and cough with sputum production. Laboratory findings demonstrated elevation of white blood cell (WBC) count in only 1 patient and elevation of C reactive protein (CRP) level in 4 patients. Radiographic examination revealed abnormal findings in the dorsal right lower lobes, which was the most vulnerable site for aspiration pneumonia, and also in the upper and ventral portions of the lung. Although the characteristic findings of PAS were scarce, all patients had conditions predisposing to aspiration; i.e., gastrectomy, excessive alcohol drinking, post-cerebral infarction, and sinobronchial syndrome. We diagnosed 9 PAS patients on the basis of histological findings that were distinct from clinical findings. Despite presenting with variable symptoms and laboratory and radiographic findings, they all exhibited predisposing factors to aspiration.