Imaging appearance of a singular metastatic adenoid cystic carcinoma of the right kidney: A case report and literature review

Abstract

Renal metastasis of a submandibular gland adenoid cystic carcinoma is clinically rare when it presents with an atypical imaging appearance of singular renal metastases. Whole-body positron emission tomography (PET)/computed tomography (CT) can determine whether the singular renal mass is benign or malignant and identify metastases in other parts of the body, particularly in uncommon sites. In the present case, the patient developed a rare partial metastasis to the right kidney three years after undergoing a surgery for submandibular gland adenoid cystic carcinoma. Based on the present case, whole-body PET/CT examination could provide an important basis for making treatment plans for singular renal metastases.

Keywords: 18F-fluorodeoxyglucose; computed tomography; metastasis; positron emission tomography; renal.

Figure 1

(A) Plain CT scan revealing a slightly lower-density mass, 5.5×5.0×5.0 cm in size, in the right kidney; the CT value was 36±5 HU. (B) Enhanced CT in arterial phase revealing a slightly enhanced mass, with a CT value of 48±5 HU. (C) Enhanced CT in the venous phase revealing an evidently enhanced lesion, with a CT value of 68±5 HU, which was high compared with the arterial phase.(D) ¹⁸F-fluorodeoxyglucose positron emission tomography-CT revealing left submandibular gland agenesis without local radioactive concentration. (E) Lump-shaped moderate radioactive concentration shadow in the lower right kidney (maximum standardized uptake value, 5.03). (F) The 5.0×6.0×5.0-cm hard mass in the lower right kidney, with a gray-white color and intact tumor capsule. (G) Hematoxylin-eosin staining of the adenoid cystic carcinoma in the right kidney (original magnification, ×40). CT, computed tomography.