Pulmonary large cell neuroendocrine carcinoma exhibiting extensive pagetoid spread in the bronchial epithelium: A case report

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive malignant tumor, which was proposed as a novel type of neuroendocrine tumor in 1991. Although it is categorized as a non-small cell lung carcinoma, the precise pathological condition is unknown due to its rare occurrence. The present study outlines the case of a patient presenting with an LCNEC that exhibited pagetoid spread from the region of the primary tumor to the bronchial epithelium (distance, >30 mm). The pagetoid spread was unconfirmed preoperatively, however, was identified by intraoperative rapid diagnosis. This caused us to suffer the perioperative decision of additional resection and resulted in an incomplete resection, as suture of the bronchus was not possible. Pagetoid spread, which is often apparent in the breast, presents as a rare pattern of infiltration of cancer cells when a massive carcinoma is identified beneath the intraepithelial spread. Although preoperative diagnosis of pagetoid spread is difficult due to its rarity and undefined clinical features, it is important for surgeons and pathologists treating lung cancer patients to be aware of potential pagetoid spread in the thoracic region.