Multiple distant metastases arising from a single, low-grade rectal neuroendocrine tumor: an autopsy case report.

BACKGROUND: Rectal neuroendocrine neoplasms are rare epithelial neoplasms of the rectum. The incidence of these tumors has increased over the past decades. However, many questions remain unanswered regarding their clinicopathology, including the possible mechanisms in which these tumors may grow and metastasize. CASE PRESENTATION: In this case report, we report the findings of an autopsy of a 65-year-old Japanese woman diagnosed with multiple liver metastases from a single, low-grade rectal neuroendocrine tumor. The diagnosis was made in late 2018 to early 2019, and subsequently the patient underwent several rounds of standard chemotherapy. However, due to unfavorable side effects, she opted for palliative care at our hospital instead from December 2020. The patient's condition was generally stable for the next 17 months, but in May 2022, she was hospitalized for increased abdominal pain. Despite enhanced pain control therapy, she eventually passed away. An autopsy was conducted to determine the exact cause of death. The primary rectal tumor was found to be small, but showed strong histological evidence of venous invasion. Metastases in the liver, pancreas, thyroid gland, adrenal glands, and vertebrae were also present. On the basis of the histological evidence obtained, we deduced that the tumor cells may have mutated and gained multiclonality as they spread vascularly to the liver, contributing to the distant metastases. CONCLUSIONS: The results from this autopsy may provide an explanation for the possible mechanism by which small, low-grade rectal neuroendocrine tumors metastasize.

Intracholecystic papillary neoplasm of the gallbladder diagnosed during follow-up of Menetrier's disease: A case report.

Intracholecystic papillary neoplasm of the gallbladder (ICPN) is a type of intraductal papillary neoplasm of the bile duct that occurs in the gallbladder, and is a relatively newer concept. Therefore, there are few reports regarding ICPN. Menetrier's disease is a rare disease characterized by giant hypertrophy of the gastric folds that causes protein-losing gastroenteropathy (PLG). Although Menetrier's disease is a known risk factor for gastric adenocarcinoma, the association between Menetrier's disease and malignancy other than a malignancy of the stomach is unclear. A 69-year-old man presented to the Hokkaido Social Work Association Obihiro Hospital with gallbladder tumours diagnosed by ultrasonography at a previous institution. In addition, he had previously been diagnosed with PLG due to Menetrier's disease. Abdominal contrast-enhanced computed tomography (CT) revealed an irregular mass with a contrast effect at the fundus of the gallbladder on the free abdominal cavity side. Positron emission tomography-CT showed a tumour with a standard uptake value (SUV) of 8.28 at the fundus of the gallbladder. Cholecystectomy and resection of the gallbladder bed were performed. Based on the microscopy findings, the patient was diagnosed with ICPN. Although he had postoperative ileus, he was discharged 14 days postoperatively due to improvement through conservative treatment. Such cases of ICPN complicated with Menetrier's disease are extremely rare. However, patients with Menetrier's disease may need to be screened for malignancies.

Bladder metastasis without hematuria, following radiation therapy for lung adenocarcinoma.

Bladder metastasis from lung adenocarcinoma is extremely rare. Unlike primary bladder urothelial tumors, the initial symptoms of this disease vary, and include pelvic pain, dysuria, and hematuria. There are few reports on cases without microscopic hematuria. An 86-year-old woman with a previous history of radiation therapy for lung adenocarcinoma complained of urinary frequency. A urinalysis was negative for hematuria and pyuria; thus, overactive bladder was suspected. However, the patient's symptom worsened considerably, and cystoscopy revealed bladder tumor. Transurethral resection of the bladder tumor was performed. Based on the histological, immunohistochemical examination and clinical history, the final pathological diagnosis was bladder metastasis from lung adenocarcinoma. The patient died 19 days after the operation due to severe disease progression. In this rare case, a patient with bladder metastasis from lung adenocarcinoma did not show microscopic hematuria. Cystoscopy and computed tomography helped to make a rapid and accurate diagnosis.