Cavernous Hepatic Hemangioma at 18F-Choline Positron Emission Tomography–Computed Tomography: Be Aware of the Pitfall

A 66-year-old man diagnosed with prostate cancer (PCa) underwent radical prostatectomy and pelvic lymph node dissection in July 2018 (pT4 pN1 pMx, Gleason score 5 + 4). Adjuvant therapy was then prescribed. Afterward, a progressive rising of PSA values was noted, and the patient was, therefore, scheduled for a positron emission tomography-computed tomography (PET-CT) scan with [18F]F-Choline (PSA trigger 1.2 ng/ml). The study demonstrated two large areas of focal uptake within the liver, respectively, at the VII and II segments [Figure 1]. Transaxial PET-CT images showed a ring of elevated tracer uptake surrounding a central area of low metabolism. These findings, of doubtful significance, were considered worthy of further investigations, mainly to exclude hepatocellular carcinoma[1] or PCa metastases.[2] A contrast-enhanced ultrasound was performed, and the findings were considered compatible with hepatic cavernous hemangioma.

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Figure 1 Maximum intensity projection shows two areas of focal [18F]F-Choline uptake within the right and left hepatic lobes (indicated by arrows) (a) Transaxial fused positron emission tomography (PET)–computed tomography (b) and emissive PET (c) images show two rings of elevated tracer uptake at the VII and II liver segments (diameter of 3 cm and 2.8 cm, respectively), surrounding a core of low metabolism

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Hepatic cavernous hemangiomas are venous malformations containing a fibrous stroma with a size ranging from millimeters to more than 10 cm.[3] They are very common and often asymptomatic and incidentally discovered. In larger cavernous hemangiomas, the central portion can contain fibrosis, thrombosis, collagen scar, or calcification, thus explaining the low metabolism of the lesion's core shown on our PET examination.

With this type of diagnosis, biopsy should be avoided due to the risk of hemorrhage; thus, the diagnosis is purely radiological. After 3 years of clinical and imaging follow-up (four PET-CT scans with [18F]F-Choline and an upper abdomen magnetic resonance imaging), the findings were stable, supporting their benign nature. While it is well-known that hepatic hemangiomas are not FDG avid,[4] to the best of our knowledge, this is the first case reporting of hepatic cavernous hemangioma at [18F]F-Choline PET-CT. Although relatively uncommon, visceral metastases from PCa can occur in the liver, heavily affecting the patient's prognosis.[5] Therefore, their detection is very relevant for the patient's tailored therapy.

Nevertheless, the physiological elevated hepatic tracer uptake at [18F]F-choline PET-CT determines a low detection rate of small metastases.[6] Moreover, the breathing artifacts may affect the upper part of the liver (the so-called “banana artifact”),[7] reducing the diagnostic accuracy of lesions localized at the hepatic dome.

Considering the relatively high incidence of hepatic hemangioma in the population (0.4% to 20%),[8] the nuclear medicine physician should be aware of this pitfall, avoiding to report a potential false-positive finding.