18F-FDG PET/CT identifies isolated metastasis of renal cancer in a patient with end-stage renal disease: A case report

Abstract

Rationale: Individuals with end-stage renal disease have a considerably higher rate of malignant tumors, especially renal cancer, in comparison to the general population. However, cases in which bone metastases in the humerus are the initial clinical presentation that results in a diagnosis of renal cancer are extremely rare. Diagnosing renal cancer in patients with end-stage renal disease can be challenging when the clinical symptoms are atypical and do not present the "renal cancer triad." Our case report highlights the diagnostic importance of positron emission tomography/computed tomography (CT) imaging, increases clinicians' awareness of the disease, explores the potential etiology of renal cancer associated with end-stage renal disease, and provides insights into diagnostic and therapeutic strategies.

Patient concerns: A 58-year-old man, who has undergone multiple renal transplants and maintenance dialysis therapy for over 20 years due to renal failure, arrived at our hospital with complaints of left shoulder pain and progressive worsening. CT revealed unexplained osteolytic destruction and fracture in the left humerus. The 18F-fluorodeoxyglucose positron emission tomography/CT scan detected soft tissue lesions in the left kidney and exhibited increased fluorodeoxyglucose uptake.

Diagnoses: Upon conducting a biopsy on the patient's left humerus, metastatic renal cancer was diagnosed.

Interventions: The patient selected conservative treatment, and the injured humerus was immobilized to stabilize the affected area. There was no additional active treatment for renal cancer.

Outcomes: As of the time of submission, the patient's pain had markedly intensified, requiring oral pain medication for symptomatic relief.

Lessons: It is indeed rare for bone metastasis in the humerus to be the initial clinical sign that leads to the diagnosis of renal cancer in patients with end-stage renal disease. Through this case report, we aimed to enhance awareness and deepen understanding of renal cancer associated with end-stage renal disease.

Keywords: PET/CT; end-stage renal disease; renal cancer.

Figure 1.

The timeline depicts the patient’s medical history and the course of diagnosis and treatment.

Figure 2.

A 58-year-old patient with end-stage renal disease (ESRD) experiencing discomfort and pain in the left shoulder for the past month. CT scans in the axial (A) and coronal (B) planes from a year ago depict numerous cysts (>3). Recent coronal (C) CT imaging indicates bone destruction and a fracture in the proximal left humerus. CT = computed tomography.

Figure 3.

The patient underwent an ¹⁸F-FDG PET/CT scan based on suspected malignant tumor. The MIP (A) images show a high ¹⁸F-FDG uptake in the left humerus. Coronal (B) and axial (D) CT images show bone destruction and soft tissue formation in the humerus, with fractures (arrows). The PET/CT fusion images (C, E) show high uptake of ¹⁸F-FDG (SUVmax, 8.6). Coronal (F) and axial (H) CT images show a soft tissue lesion in the lower part of the left kidney. PET/CT fusion images (G, I) show moderate uptake of ¹⁸F-FDG (SUVmax, 3.1). ¹⁸F-FDG PET/CT = ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography, CT = computed tomography, MIP = maximum intensity projection.