Mixed adeno(neuro)endocrine carcinoma arising from the ectopic gastric mucosa of the upper thoracic esophagus

Abstract

We report a case of mixed adenoendocrine carcinoma of the upper thoracic esophagus arising from ectopic gastric mucosa. A 64-year-old man who had been diagnosed with an esophageal tumor on the basis of esophagoscopy was referred to our hospital. Upper gastrointestinal endoscopy revealed the presence of ectopic gastric mucosa and an adjacent pedunculated lesion located on the posterior wall of the upper thoracic esophagus. Subtotal esophagectomy with three-field lymph node dissection was performed. A microscopic examination revealed that there was a partially intermingling component of neuroendocrine carcinoma adjacent to a tubular adenocarcinoma which was conterminous with the area of the ectopic gastric mucosa. Although the tubular adenocarcinoma was confined to the mucosa and submucosa, the neuroendocrine carcinoma had invaded the submucosaand there was vascular permeation. Each component accounted for 30% or more of the tumor, so the final histopathological diagnosis was mixed adenoendocrine carcinoma of the upper thoracic esophagus arising from ectopic gastric mucosa. Adjuvant chemotherapy was not performed, because the postoperative tumor stage was IA. The patient was well and had no evidence of recurrence 16 months after surgery.

Figure 1

Upper gastrointestinal endoscopic findings regarding the pedunculated tumor. (a) Endoscopy revealed ectopic gastric mucosa 19 to 21 cm distal from the incisors on the oral side of the pedunculated tumor (arrowheads). (b) A pedunculated lesion was located on the posterior wall of the upper thoracic esophagus 21 to 23 cm distal from the incisors, adjacent to the area of ectopic gastric mucosa (arrowheads).

Figure 2

Gross findings of the resected specimen. The pedunculated tumor, which measured 17 × 15 mm, is indicated within the red outline adjacent to a rough area 36 × 30 mm in size, which is indicated within the white outlines. The area within the yellow outline was composed of neuroendocrine carcinoma. The relationship between the NEC and adenocarcinoma components was confirmed on the green line in Figure  3.

Figure 3

Histopathologic findings. (a) A low-power view of the line (from A to B) shown in Figure  2. The neuroendocrine carcinoma (NEC) and adenocarcinoma components of the tumor were adjacent and partially intermingled. The NEC component had invaded the submucosa with vascular permeation (arrow). (b) The NEC component showed a positive response for CD56 staining (immunohistochemical stain). (c) A magnified view of the squared area at the left in (a). The NEC component showed a solid and trabecular pattern, and the tumor cells had elongated hyperchromatic nuclei and scant cytoplasm (hematoxylin and eosin stain (H&E); original magnification, ×117). (d) A magnified view of the squared area in the middle in (a). A borderline area of NEC and well-differentiated adenocarcinoma showed a histological transition (H&E; original magnification, ×117). (e) A magnified view of the squared area at the right in (a) showing well-differentiated tubular adenocarcinoma confined to the mucosa and submucosa (H&E; original magnification, ×117).