We report 3 cases of solitary papillomas located in peripheral regions of the lung that are extremely rare in the literature. The patients were 75-year-old and 72-year-old men and a 53-year-old woman. One patient complained of recurrent hemoptysis. The other 2 had no symptoms, but abnormal nodular shadows were revealed by chest radiographs during a health check. The maximum diameters of the tumors were 1.0, 1.4, and 1.1 cm, respectively. The 3 tumors gave almost the same histologic findings. Papillomatous fronds lined by a stratified columnar epithelium were seen in the lumens of peripheral bronchi, bronchioles, or alveoli. The stratified columnar epithelium consisted of ciliated, mucous, and basal cells. The neoplastic epithelium extended to the alveolar region and showed a similar appearance to bronchioloalveolar or papillary type adenocarcinomas. For differential diagnosis, it is noteworthy that endobronchiolar papillomatous fronds constantly exist and spreading along alveolar walls is limited in adjacent alveoli in peripheral papillomas. The presence of ciliated cells and basal cells is considered an important finding to suggest benign character of the lesion.
Two patients underwent uneventful total removal of convexity or trigone meningioma, but subsequently edema enlarged causing symptoms 3-4 weeks later. Gradual improvement was obtained by steroid administration in 1 patient and re-craniotomy in 1 patient. The histological findings in Case 1 were not confirmed, but inflammatory reaction against residual microfibrillar collagen hemostat (MCH) may have developed. The specimen from around the cyst in Case 2 showed moderate staining for vascular endothelial growth factor (VEGF). VEGF secreted by the tumor might have resulted in spread of inflammation due to MCH in the brain parenchyma. Furthermore, inflammatory reactions may have obstructed or formed a one-way communication in the inferior horn and residual cavity, resulting in malabsorption of cerebrospinal fluid. Postoperative edema with the timing in these cases is difficult to anticipate. However, the risk of this phenomenon can probably be minimized by ensuring that MCH is removed as effectively as possible after use, or by refraining from use in the brain parenchyma and by taking care to connect the residual cavity to the ventricular system, particularly if the tumor contacts a cerebral ventricle.
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