大城 久

INTRODUCTION: Laimer's diverticulum (LD) is a rare pharyngoesophageal diverticulum that originates from the posterior wall of the cervical esophagus and beneath the cricopharyngeal muscle (CPM). Carcinoma arising in pharyngoesophageal diverticula occurs predominantly in association with Zenker's diverticulum (ZD), whereas its occurrence in LD is exceptionally rare. We report a rare case of superficial squamous cell carcinoma that originated in LD. CASE PRESENTATION: A 78-year-old man with a known esophageal diverticulum presented with a 9-year history of progressive dysphagia and regurgitation of food. Esophagography and contrast-enhanced computed tomography demonstrated a large posterior diverticulum originating from the cervical esophagus below the cricoid cartilage. Diverticulectomy was performed through a left cervical approach. Intraoperative findings confirmed that the diverticulum originated from the posterior wall of the cervical esophagus, inferior to the CPM, consistent with LD. Histopathological examination revealed an intra-diverticular 15 mm × 10 mm squamous cell carcinoma in situ (pT1a-EP). Surgical margins were negative, and the postoperative course was uneventful. DISCUSSION: Accurate anatomical differentiation among types of cervical esophageal diverticula is essential because treatment strategies may differ substantially among LD, ZD, and Killian-Jamieson diverticulum. Endoscopic identification may be difficult because retained food debris, chronic inflammatory changes, and the narrow diverticular lumen can conceal superficial lesions; meticulous cleaning and enhanced endoscopic observation, including narrow-band imaging or Lugol chromoendoscopy, may improve detection in similar cases. Misdiagnosis of LD as ZD may result in inappropriate treatment selection, particularly when endoscopic septotomy is considered. CONCLUSION: We report a rare case of superficial squamous cell carcinoma originating in LD. Careful anatomical assessment is essential for accurate diagnosis and appropriate surgical management of cervical esophageal diverticula. This case underscores the importance of early surgical excision or regular surveillance when cervical esophageal diverticula are managed nonoperatively.

INTRODUCTION: Esophageal schwannomas are rare, benign tumors arising from Schwann cells in the esophageal wall. Giant forms are particularly rare and can resemble mediastinal tumors, making preoperative diagnosis difficult. CASE PRESENTATION: Herein, we present the case of a 55-year-old man with hypertension, obesity, and obstructive sleep apnea syndrome who was referred for evaluation of a large mediastinal mass. The lesion was incidentally discovered 7 years earlier and was monitored without intervention. Chest computed tomography (CT) revealed a well-circumscribed middle mediastinal mass measuring 93 × 91 × 73 mm3, compressing the esophagus. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased uptake, with a maximum standardized uptake value of 10.156, suggesting malignancy. However, endoscopic ultrasonography failed to provide a definitive diagnosis. Due to tumor growth and the inability to rule out malignancy, surgical resection was performed. A right thoracotomy with subtotal esophagectomy and retrosternal gastric tube reconstruction was performed. Histopathological examination confirmed that the lesion was a benign esophageal schwannoma. The patient recovered uneventfully and has remained recurrence-free for 1 year postoperatively. CLINICAL DISCUSSION: Giant esophageal schwannomas are rare and pose diagnostic challenges, particularly because of their potential for high FDG uptake despite their benign pathology. Complete surgical excision remains the definitive treatment for this condition. The choice of surgical approach should be guided by tumor size, location, and involvement of surrounding structures. CONCLUSION: This case highlights the diagnostic difficulties and surgical management of giant esophageal schwannomas. Clinicians should consider this rare condition in the differential diagnosis of large mediastinal masses. This case also underscores the importance of surgical decision-making in the context of diagnostic uncertainty and tumor size, contributing to the limited literature on giant esophageal schwannomas requiring esophagectomy.

OBJECTIVES: To compare functional and oncological outcomes among the novel anterior approach, the Retzius-sparing approach, and the conventional anterior approach for robot-assisted radical prostatectomy. METHODS: This retrospective cohort study included 585 patients who underwent robot-assisted radical prostatectomy between September 2017 and August 2022 at Jichi Medical University Saitama Medical Center. Among them, 173, 109, and 303 patients underwent the novel anterior approach, the Retzius - sparing approach, and the conventional anterior approach, respectively. Urinary continence recovery was evaluated as the primary endpoint, while postoperative inguinal hernia incidence and oncological outcomes, including surgical margins and biochemical recurrence-free survival, were assessed as secondary endpoints and compared using Kaplan-Meier methods. RESULTS: Patient characteristics did not differ across groups except for surgeon's experience and follow-up duration. Both the Retzius-sparing approach and the novel anterior approach were associated with earlier recovery of complete continence (HR = 3.10, 95% CI 2.26-4.26; HR = 1.60, 95% CI 1.25-2.04) and a lower incidence of inguinal hernia (HR = 0.34, 95% CI 0.19-0.62; HR = 0.23, 95% CI 0.13-0.42) compared with the conventional anterior approach. Biochemical recurrence-free survival did not differ significantly among the three approaches, despite the higher rate of positive surgical margins in the Retzius-sparing approach. CONCLUSIONS: The novel anterior approach and the Retzius-sparing approach may offer functional advantages over the conventional anterior approach, while oncological outcomes appear comparable across groups in this retrospective cohort. These hypothesis-generating findings suggest the need for further prospective studies with longer follow-up.

INTRODUCTION: Spontaneous tumor regression (STR) is a rare phenomenon in which cancer cells partially or completely disappear without treatment. We report a case of intrahepatic cholangiocarcinoma demonstrating STR following endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA). CASE PRESENTATION: A 77-year-old male presented with acute cholecystitis 1 day after percutaneous coronary intervention for acute myocardial infarction. Conservative treatment and endoscopic retrograde gallbladder drainage were performed due to antiplatelet therapy. Cytology of bile juice unexpectedly revealed adenocarcinoma. Further imaging, including CT and mapping biopsy, failed to detect a tumor. Laparoscopic cholecystectomy with gallbladder bed resection showed no histological evidence of malignancy. Four months later, surveillance CT revealed a 15 × 15 mm lesion in segment 3 of the liver. EUS-FNA confirmed adenocarcinoma. Laparoscopic left lateral resection was performed; however, no viable cancer cells were identified, and the lesion was replaced by epithelioid granulomas. Immunohistochemistry demonstrated dense infiltration of CD8-positive cytotoxic T cells, suggesting an immune-mediated regression of the tumor. CONCLUSIONS: This case highlights the possibility of tumor regression in intrahepatic adenocarcinoma following EUS-FNA, potentially triggered by an immune response.