Liver metastasis from adenoid cystic carcinoma: imaging and histologic features

Surgical treatment of liver and kidney metastasis from an adenoid cystic carcinoma of the submandibular gland: case report

INTRODUCTION

Adenoid cystic carcinomas (ACCs) account for 10% of all malignant salivary tumours. They are slow-growing but locally aggressive. Reports of liver and renal metastases are rare.

CASE DESCRIPTION

A 58-year-old woman who had undergone resection of a left submandibular ACC in 1995 was referred to our centre for follow-up in 2018. A computed tomography scan revealed two lesions: one on segment six of the liver and the other on a kidney. A hepatic wedge resection and right nephrectomy were performed. The postoperative course was uneventful. At 2-year follow-up, the patient was alive and well with no evidence of disease.

CONCLUSION

Management of ACC is a therapeutic challenge because of its tendency for distant metastases. The literature recommends regular follow-up imaging and radical surgical treatment but specific guidelines for the approach to recurrence are lacking.

FDG-PET/CT imaging findings of hepatic tumors and tumor-like lesions based on molecular background

The usefulness of whole-body 18-fluoro-2-deoxyglucose (FDG)-fluorodeoxyglucose positron emission (PET)/computed tomography (CT) is established for assessment of disease staging, detection of early disease recurrence, therapeutic evaluation, and predicting prognosis in various malignancies; and for evaluating the spread of inflammation. However, the role of FDG-PET/CT for the liver is limited because CT and magnetic resonance imaging (MRI) can provide an accurate diagnosis of most tumors. In addition, in other potentially useful roles there are several pitfalls in the interpretation of FDG uptake in PET/CT imaging. Accurate evaluation demands knowledge of the FDG uptake of each lesion, including potential negative and positive uptakes, and requires an understanding of the underlying background of the molecular mechanisms. The degree of FDG uptake is dependent on cellular metabolic rate and the expression of glucose transporter, hexokinase, and glucose-6-phosphatase, which in turn are closely affected by biological characteristics such as pathological category (e.g., adenocarcinoma, squamous cell carcinoma, small cell cancer, transitional cell cancer, neuroendocrine tumor, sarcoma, lymphoma), tumor differentiation, histological behavior (e.g., solid, cystic, mucinous), and intratumoral alterations (e.g., necrosis, degeneration, hemorrhage). Correlation with the CT and MRI findings, which also precisely depict the pathological findings, is important to avoid misdiagnosis.