A 72-year-old gentleman with locally advanced non-small cell lung cancer in the left upper lobe for which he has previously received radical radiotherapy. Presented for a surveillance CT scan which demonstrated new “sclerotic” appearing foci in multiple vertebrae with a subsequent elevated PSA of 6.
A contrast-enhanced CT thorax demonstrated new hyperdense foci (HU 1500–1790) within the C7–T3 vertebrae (Figures 1a, 1b, 1c and 1d) with contrast administered via the left antecubital fossa (ACF). CT scans performed 4 months prior (Figure 2) and 3 months after (Figure 3) the index scan in which the right ACF was used for contrast administration demonstrated no hyperdense foci.
Prominent venous collateral pathways via the left lateral thoracic, T8 intercostal and accessory hemiazygos veins are demonstrated with engorgement of the paravertebral veins and the vertebral venous plexus on the index scan (Figure 4). The vertebral venous plexus demonstrates engorgement of the posterior external vertebral plexus and the anterior and posterior internal vertebral venous plexus with enlargement of the basivertebral vein and intra-osseous venous plexus (Figure 5).
A left apical lung tumour with post-radiotherapy scarring and narrowing of the left subclavian and brachiocephalic veins is demonstrated (Figure 6).
Background
Vanishing bony metastases can occur secondary to the compromise of the normal venous drainage with diversion of intravenous contrast administered in upper limbs through collateral pathways resulting in hyperdense foci appearing in unexpected locations such as the vertebrae [1]. Multiple venous collateral pathways have been described, which can result in diversion of contrast to different locations depending on the position of the impedance, with the vertebral venous route manifesting in this scenario [2,3]. The cause of collateral formation is normally secondary to occlusion or compression of the superior vena cava, subclavian or brachiocephalic veins due to an adjacent lesion or thrombosis due to previous central venous access.
Clinical Perspective
The presentation of vanishing metastases will often itself be detected incidentally while under investigation for other pathology or while undergoing surveillance of a known disease process. In this case, an incidental elevated PSA was obtained on recognition of the potential sclerotic foci raising the possibility of a synchronous metastatic prostate cancer. Of course, clinically, this would have a significant impact on the patient’s care pathway, including the treatment level and prognostication. Identification of vanishing bone metastases can prevent significant burden for the patient both to their general wellbeing and through avoiding unnecessary interventions. Subsequent PSA testing demonstrated a reduction to acceptable levels.
Imaging Perspective
Contrast-enhanced CT may demonstrate hyperdense bony foci, which can masquerade as osteoblastic metastases [4,5]. These foci can be rounded and accompanied by multiple collateral vessels. A review of recent previous imaging may demonstrate these hyperdense foci when contrast has been administered using the same side as the central venous narrowing/occlusion, which will, however, not be present when contrast has been administered via the contralateral arm.
Outcome
Identification of this phenomenon as a potential cause of new sclerotic appearing foci is key in preventing unnecessary patient distress and intervention. Consideration of the side of contrast administration and identification of any potential central venous impedance can prevent this occurrence. In the setting of lung cancer, particularly apical tumours, the use of the contralateral side for contrast administration should be standard practice.
Take Home Message / Teaching Points
In patients with known central venous impedance or high-risk lung cancer, the contralateral arm should be used for contrast administration. This should be recorded on the patient’s record to prevent future scans from falling victim to this phenomenon.
Written informed patient consent for publication has been obtained.
Vanishing bony metastases
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The follow-up CT primarily shows multiple vertebral bodies in the cervical-thoracic region (including, but not limited to, the cervical and upper thoracic vertebrae) exhibiting sclerotic-like high-density appearances. These are visually similar to conventionally described osteosclerotic lesions.
On axial and sagittal reconstructed images, these “sclerotic-like” high-density areas appear as relatively well-defined clusters or patchy distributions, with some lesions seeming to be adjacent to the vascular pathways of the vertebral bodies.
Additionally, on certain images, abnormally thickened veins or signs of collateral circulation are observed, suggesting possible venous return abnormalities caused by compression or obstruction of local vasculature.
Comparing with previous imaging, when the contrast agent is injected from different upper limb veins, the appearances of these high-density lesions are inconsistent. This indicates that they may not be true osteosclerotic or metastatic bone lesions, but rather could be related to shunting of the contrast agent within abnormal venous pathways.
After a comprehensive review of the patient’s history (72-year-old male with previous left upper lobe non-small cell lung cancer treated with radiotherapy, transient PSA elevation followed by normalization), imaging characteristics (multiple high-density lesions related to contrast method and collateral venous circulation), and follow-up (inconsistent presentation of lesions when contrast was injected on different sides over a short period), the most plausible explanation is:
“Vanishing Metastases” — a pseudo-sclerotic phenomenon in bone.
If there is still uncertainty, the following options may be considered:
1. Treatment Strategy:
Since true bone metastases are essentially ruled out in this case, follow-up management focuses on:
2. Rehabilitation and Exercise Prescription:
Given the patient’s advanced age of 72 and pulmonary function status, an exercise plan should be tailored to his cardiorespiratory endurance, musculoskeletal health, and post-radiotherapy conditions. A moderate, gradual approach helps improve fitness and maintain quality of life. The FITT-VP principle may be referenced:
During exercise, it is important to monitor:
Disclaimer: This report is a reference-based analysis derived from the provided medical history and imaging. It is not a substitute for in-person consultation or professional medical advice. In case of any concerns or changes in symptoms, it is recommended to seek medical attention and undertake further professional assessment.
Vanishing bony metastases
