Radiation-induced hepatitis masquerading as metastatic disease: the importance of correlating diagnostic imaging with treatment planning

Abstract

We are presenting a 63-year-old Caucasian male who complained of 2 months of progressive dysphagia. Upper endoscopy discovered a mass in the distal esophagus near the gastroesophageal junction.Biopsy was consistent with adenocarcinoma. Endoscopic ultrasound (EUS) showed extension beyond the muscularis propria, with an enlarged paraesophageal lymph node (T3N1). Initial positron emission tomography (PET)/computed tomography (CT) showed hypermetabolic portocaval lymphadenopathy presumed to be metastatic, but otherwise without distant disease extension. Neoadjuvant treatment included induction FOLFOX followed by 5,600 cGy over 28 fractions in combination with 5-FU and oxaliplatin. Approximately 3.5 weeks after completion, a repeat PET/CT revealed reduced uptake in both the primary esophageal mass and regional lymph nodes. Of note there were several new mass-like foci of hypermetabolism in the liver, specifically the left lobe, concerning for metastatic disease. Image-guided biopsy did not show any identifiable lesions, but sampling was performed based on anatomical landmarks.Pathology revealed benign parenchyma with minimal inflammation and mild reactive regeneration. In light of this, the patient proceeded to undergo definitive resection via robotic Ivor-Lewis esophagectomy with only 1 positive lymph node. Given pleural involvement by the tumor, staging was revised to pT4aN1 with final histology characterized as adenosquamous carcinoma. Postoperative course was fairly uneventful, with a mild exacerbation of his chronic heart failure. The patient was discharged on post-operative day 7, with his feeding tube removed at his 2-week post-operative clinic visit. This scenario is of particular educational value from the standpoint that when the post-treatment PET/CT images are registered to the radiotherapy treatment planning CT and dose, the areas of abnormal uptake in the liver fall within the higher dose regions. Given this and the liver biopsy findings, caution should be exercised before declaring progressive disease following radiotherapy without first reviewing the treatment plan.

A Discordant Pattern of Uptake on 68Ga-PSMA PET/CT Versus 18F-Fluciclovine PET/CT in Radiation-Induced Hepatitis

“…Inflammation accompanying postradiation hepatitis has been previously reported on FDG PET/CT. 1,2 To our knowledge, the appearance of radiation-induced hepatitis on 68 Ga-PSMA and 18 F-fluciclovine PET/CT has not been previously reported. The discordant findings in this patient may have implications for postradiotherapy response assessment using these radiotracers in the acute timeframe.…”

“…In distinction, the reduced uptake on 18 F-fluciclovine PET may be due to reduced amino acid utilization in radiation-damaged hepatic cells, reflecting diminished metabolism. Inflammation accompanying postradiation hepatitis has been previously reported on FDG PET/CT 1,2 . To our knowledge, the appearance of radiation-induced hepatitis on 68 Ga-PSMA and 18 F-fluciclovine PET/CT has not been previously reported.…”