A 60-year-old man was diagnosed with esophageal cancer found incidentally on upper gastrointestinal endoscopy during a health examination. A superficial irregular ulcerative area was observed in the middle to lower third of the thoracic esophagus (Figure 1a), with an elevated lesion covered by normal epithelium found caudal to the main lesion (Figure 1b). A biopsy specimen of the latter obtained during the health examination was histologically shown to be a squamous cell carcinoma. Iodine staining showed that the lesion was about 6.0 cm in diameter and occupied two thirds of the esophageal lumen (Figure 1c). Narrow-band imaging showed highly destroyed intrapapillary capillary loops in the ulcerative area, indicating tumor invasion of the submucosal layer (Figure 1d). Endoscopic ultrasonography with a 20-MHz transducer estimated the depth of tumor invasion as cT1b (SM1). Histological examination of the biopsy specimen collected from the ulcerative lesion showed squamous cell carcinoma. Computed tomography scan could not detect the primary tumor in the esophagus, but detected an enhanced swollen lymph node, 0.8 cm in diameter, in the dorsal area of the thoracic aorta (Figure 2a), as well as a swollen lymph node along the left gastric artery (Figure 2b). F-deoxyglucose (FDG) positron emission tomography showed high FDG uptake by the esophageal tumor, as well as by the retroaortic (Figure 2c) and perigastric (Figure 2d) lymph nodes. These lymph nodes were suspected of being metastases of esophageal cancer. The patient was diagnosed with a superficial, esophageal squamous cell carcinoma in the middle and lower thoracic esophagus with intramural metastasis and perigastric and distant lymph node metastases, and was classified as having cT1bN4M0IM1 stage IVa according to the Japanese classification of esophageal cancer [3,4]. Although the recommended therapeutic strategy for stage IV disease is not surgery, we tried to resect all metastatic lymph nodes to confirm the cancer spread by histopathologic examination. The patient underwent video-assisted thoracoscopic esophagectomy in the left lateral position [5] with three-field lymph node dissection. HALS was used for all abdominal procedures. The retroaortic lymph node could not be identified by a thoracoscope inserted into the right thoracic cavity. The metastatic lymph node in the dorsal area of thoracic aorta was identified by mediastinal scope inserted from abdominal port and dissected by HALS using a transhiatal approach and a pneumomediastinum method [6]. Following thoracoscopic surgery for mediastinal lymph node dissection and esophageal transection in the upper mediastinum, the patient was placed in the supine position and underwent the HALS procedure. A 7-cm upper-abdominal median incision was created for insertion of the operator’s left hand. Four ports were inserted as shown in Figure 3. Carbon dioxide was introduced into the intra-abdominal space, and pressure in the pneumoperitoneum was controlled at 10 mmHg. After usual gastric mobilization and abdominal lymph node dissection, the esophagus was pulled down to the abdominal cavity from the esophageal hiatus. After enlargement of the esophageal hiatus, the adventitia of the thoracic aorta were exposed near the crura of the diaphragm, from the anterior to the left side and then to the dorsal side, in that order. Using pneumomediastinum and anterior retraction of thoracic aorta enabled visualization of the anatomy around the dorsal area of the thoracic aorta. A swollen lymph node between the dorsal side of the aorta and the hemiazygos vein was dissected, along with surrounding fatty tissue, using an EnSeal device (Ethicon, Cincinnati, OH, USA) without injuring the hemiazygos vein and intercostal arteries (Figure 4). A gastric conduit was created and raised through the posterior mediastinal route. The operation was completed by cervical esophagogastrostomy with circular stapling. The patient’s postoperative clinical course was uneventful, without postoperative bleeding, chylothorax, or anastomotic leakage. However, he experienced delayed, left recurrent laryngeal nerve palsy, which became apparent 1 week after surgery but disappeared 3 months later. The patient underwent two courses of adjuvant chemotherapy, consisting of CDDP and 5-fluorouracil. At present, 1 year and 8 months after surgery, the patient remains alive without tumor recurrence.
Postoperative histopathological examination showed proliferation of the squamous cell carcinoma to the MM layer, with intraepithelial spread in the esophagus (Figure 5a,b,c). The primary tumor showed high lymphatic invasion (Figure 5d). The elevated lesion caudal to the primary tumor was found to be an intramural metastasis (Figure 5e), located primarily in the mucosal layer of the lamina propria and partly in the submucosal layer. Two lymph node metastases were found, one in the dorsal area of the thoracic aorta (0.8 cm in size, Figure 5f) and the other along the left gastric artery (2.0 cm in size, Figure 5g). Therefore, the pathological diagnosis was MtLt, 47 mm, 0-IIa + IIb, pT1a-MM, ie(+), INF-b, ly3, v0, pN4(4a), pIM1, M0, and pstage IVa.
