Masses of the adrenal gland
- In childhood
  - US is primary modality
- In adults
  - CT is primary modality
  - US
  - MRI with in phase – out phase
- Haemorrhage
  - US
  - CT
Masses of the kidney
- Kidney cysts
  - US
    - Hypoechoic/anechoic cysts
- Benign tumors
  - US
- Renal cancer
  - CT in adults
  - US in children
Masses of the prostate
- Modality
  - Transrectal ultrasound
    - Also used to guide biopsy for definitive diagnosis
  - MRi

Diseases of the testicles
- Testicular cancer
  - Ultrasound
- Testicular torsion
  - Doppler ultrasound shows reduced perfusion in affected testicle

Adrenal adenoma

Adrenal adenomas are small (1 – 5 cm), yellow, soft benign adrenal tumours. Only a small percentage of them are functional (hormone-secreting), while the majority are non-functional.

Adrenal tumours are often discovered incidentally on CT imaging, giving them the nickname adrenal incidentaloma. In most cases, these incidentalomas are harmless non-functional adrenal adenomas. Incidentalomas are found on 0,3 – 5% of abdominal CT scans and are therefore quite common.

Evaluation

Certain CT characteristics increase the risk of the incidentaloma being adrenal carcinoma. Benign findings include small size, low density (< 10 HU) due to containing mostly adipose tissue, smooth border, rapid contrast washout. Malignant findings include irregular shape, inhomogeneous density, and delayed contrast washout. MRI with in-phase and out-phase can also help distinguish it from carcinoma.

Renal cancer

Renal cell carcinoma (RCC) is the most common histological type of renal cancer in adults, accounting for 80+%. It's a malignant epithelial tumor that arises from the kidney tubules. It's usually discovered incidentally. When symptomatic, it usually presents with a classic triad of haematuria (with normal and not dysmorphic RBCs), costovertebral pain and/or a palpable mass in the flank.

It's a relatively rare malignancy, with an incidence of 15/100 000 new cases every year. It's mostly a disease of elderly men. Most are diagnosed with localised disease. Up to 70% of cases are incidentally diagnosed on imaging.

Imaging

CT with contrast is required to make the diagnosis, but ultrasound is sometimes the first imaging modality used. Ultrasound may show an expanding hyperechoic or hypoechoic process. On CT renal cell carcinoma is visible as the tumour enhances with contrast. Invasion of the renal vein is common. Following the diagnosis, CT of the thorax should be made to look for metastasis.

Staging

The TNM staging of kidney tumors depend on the size, renal vein involvement and local invasion. 7 cm in size is the border between T1 and T2 tumours. Kidney tumors commonly infiltrate the fatty capsule and when they do they are T3. If they infiltrate beyond the renal fascia (Gerota fascia) the cancer is considered T4 and therefore inoperable.

Wilms tumour

Wilms tumour, also called nephroblastoma, is a tumour of the metanephric blastema. It’s the most common renal tumour in childhood. It mostly presents before the age of 5. 5% of cases are bilateral.

Diagnosis and evaluation

Imaging shows the mass, but for children ultrasound is usually the first choice over CT/MRI. Imaging shows a characteristic renal mass. As part of the preoperative evaluation, it’s important to assess for lung metastases and the function of the contralateral kidney.

Bladder cancer

Bladder cancer is the most common cancer of the urinary system. The most common histological type is urothelial carcinoma, previously called transitional cell carcinoma (90% of cases). The remaining cases are squamous cell carcinoma and adenocarcinoma.

Diagnosis and evaluation

Haematuria on urine analysis is seen in most cases of bladder cancer. Urine cytology may show cancer cells.

Patients suspected of having bladder cancer should be referred to cystoscopy. Cystoscopy allows for taking biopsy sample, cytology sample, or even resecting the tumour in its entirety in some cases. Photodynamic diagnosis (PDD) is often used in cystoscopy, where a fluorescent dye called hexyl aminolevulinate (HAL, Hexvix®) is administered into the bladder. Cancer cells absorb this dye and glow red or pink when special fluorescent light is shone from the cystoscope, making them easier to see.

CT with contrast is the first choice imaging modality if bladder cancer is suspected based on cystoscopy. It allows for visualisation of the local spreading of the malignancy. Because contrast is filtered by the kidneys, it enters the urinary tract, and a tumour may therefore produce a filling defect. If the tumour has invaded the bladder wall, it will appear thickened on the CT. CT urography also allows for examination of the entire urinary tract, as bladder cancer is often multifocal. CT abdomen and pelvis to look for metastasis is also indicated for staging. In Norway, CT of the abdomen is performed before cystoscopy (because positive findings may allow the patient to skip cystoscopy and proceed directly to TUR-B).

Stages

Non-muscle invasive bladder cancer (NMIBC), also called stage I, refers to when the disease has not invaded the muscle of the urinary bladder. Muscle-invasive disease (MIBC) may be stage II or III, depending on how far it has spread locally. Metastatic disease is stage IV, where metastasis is present.

Non-muscle invasive and muscle-invasive disease can only be distinguished by transurethral resection of the bladder or by MRi. CT cannot distinguish them.