Tumour-to-tumour metastasis

A tumour-to-tumour metastasis, also known as a collision tumour, is a rare metastatic process in which a primary malignant tumour ('donor') metastasises to another tumour ('recipient'), most commonly a benign tumour such as a meningioma.

Tumour-to-tumour metastasis is considered very rare, with one recent 2012 review uncovering only 84 cases in a literature search 1

Clinical presentation is highly variable depending on the primary donor tumour and the tumour to which it is metastasising to 1-3.

The most common recipient of these metastases are meningiomas with the most common donor tumours being breast and lung cancers, however many different donor (e.g. renal cell carcinoma, prostate cancer) and recipient tumours (e.g. renal cell carcinomathymoma, uterine leiomyoma) have been reported 1-4

Meningiomas are the most common recipient tumour and although the reasons for why this is so remain unclear, it has been postulated that they have many characteristics that promote tumour growth, such as slow growth rate, hypervascularity, high collagen, and high lipid content 1.

Similar to clinical presentation, radiographic features are highly variable and often CT and MRI alone are not sufficient to confidently make the diagnosis of tumour-to-tumour metastasis 1.

As meningiomas are the most common recipient tumour, they are most commonly described radiographically in the literature 1. In general, unusual radiographic characteristics and unexpectedly rapid growth in a meningioma may be prompts to consider this rare diagnosis 5.

Appearance is variable, with the metastasis within a meningioma appearing as either hyperdense over the meningioma, or hypodense if it has a necrotic component 1

Again highly variable, MRI reveals signal characteristics that are unusual for a meningioma 1. MR spectroscopy and MR perfusion may be additionally utilised to detect further characteristics atypical for meningioma 1.

Treatment involves resection, which is often necessary for diagnosis anyway, and management of the primary tumour 1. Prognosis is that of the metastasised primary malignancy.

Tumour-to-tumour metastasis was first described by Berent in 1902 4,6.

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Article information

rID: 25591
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Collision tumour
  • Tumor-to-tumor metastasis
  • Tumour-to-tumour metastases
  • Tumor-to-tumor metastases
  • Tumour to tumour metastasis
  • Tumour to tumour metastases

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Cases and figures

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    Figure 1: histology (HCC to meningioma)
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    Case 1: CT brain (HCC to meningioma)
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    Figure 2: histology (lung cancer to meningioma)
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    Case 1: MRI brain (HCC to meningioma)
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    Case 1: CT abdomen (HCC to meningioma)
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    Case 2: CT brain (lung cancer to meningioma)
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    Case 2: MRI brain (lung cancer to meningioma)
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    Case 2: CT chest (lung cancer to meningioma)
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