[Resumption of Enfortumab Vedotin Supported by Diagnosis of a Late- Onset Immune-Related Adverse Event in Metastatic Urothelial Carcinoma : A Case Report].

A 71-year-old man presented with exertional dyspnea. Chest radiography revealed multiple pulmonary nodules, and contrast-enhanced computed tomography showed findings suspicious of right renal pelvic cancer. Percutaneous lung tumor biopsy revealed a histological diagnosis of urothelial carcinoma, and right renal pelvic cancer cT3N2M1 was diagnosed. Favorable response was shown during primary chemotherapy with gemcitabine and cisplatin but resulted in tumor progression after four cycles. The patient was switched to a second-line treatment, pembrolizumab, which resulted in rapid tumor growth. Hyper-progression was suspected, and the patient was promptly switched to a third-line treatment, enfortumab vedotin. The tumor shrank significantly. After three treatment cycles, an adverse event of enteritis was observed. A biopsy of the intestinal mucosa led to a histopathologic diagnosis of late-onset immune-related adverse event; therefore, enfortumab vedotin could be continued.

Primary Gastrointestinal Stromal Tumor of the Liver with Cystic Changes.

Gastrointestinal stromal tumors (GISTs) are known to originate specifically from the intestinal cells of Cajal located in the gastrointestinal mesenchyme. GISTs developing outside of the digestive tract have barely been reported. We encountered a first case of large primary GISTs in the liver with cystic changes. A 63-year-old man with a past history of brain infarction visited our hospital. The computed tomography (CT) revealed a 6-cm and a 10-cm mass in the right and the caudal lobe of the liver, respectively. These tumors have marginal enhancement in the arterial phase; however, they presented as hypodense in the internal tumor sites. Both liver tumors had cystic changes. Gastrointestinal examinations using endoscopy revealed no other gastrointestinal tumors, and [18F]-fluoro-2-deoxy-D-glucose positron emission tomography/CT revealed multiple bone metastases in addition to the liver tumors. The liver tumor specimens were composed of spindle cells, and the immunohistochemical staining for c-Kit and for DOG1, as discovered on GIST, was positive. The patient was diagnosed with primary hepatic GIST with cystic changes.