gms | German Medical Science

Objective: With roughly 200 cases published world-wide since 1930, combination tumours such as collision tumours and tumour-to-tumour metastases (TTM) pose rare constellations of neoplastic disease with their clinical relevance still being a matter of debate.

Methods: Among all patients operated on intracranial or spinal glioma, meningioma, hematoma, or hemangioblastoma between 2009 and 2020 in our hospital we selected those with concomitant neoplastic disease (primarily high-grade glioma, lymphoma, or carcinoma) and retrospectively evaluated all diagnostic and surgical reports to identify cases of combination tumours, which we then aggregated into a descriptive analysis.

Results: In our cohort of 665 patients, we have identified 8 patients with combination tumours (1.2 %). In all cases, the benign “host” tumour was a meningioma, whereas the malignant tumour mostly derived from adenocarcinomas of the breast, lung, or prostate (62.5 %) on the one hand, or B-cell lymphoma and glioblastoma (12.5 % respectively) on the other hand. The patients’ age ranged from 48 to 81 years (ratio female/male 1:1). In 62.5 % of cases, the malignant tumour was previously known with a median latency of 9 years (range: 7 months to 14 years) until manifestation of the combination tumour. Hence, 50.0 % of patients had already received chemotherapy. However, none of them had received previous cranial radiotherapy. Notably, in 3 patients identification of a concomitant tumour was first achieved in the context of a collision tumour or TTM. Following re-evaluation of preoperative MRI reports, a combination tumour had been considered in only 25.0 % of cases.

Conclusion: With regard to the current literature, we provide one of the largest clinical series of combination tumours from one single institution. Our cohort supports the notion that meningiomas are common hosts in combined tumours, indicating the existence of permissive features regarding the growth of malignant entities, especially metastases of adenocarcinoma, but also glioblastoma or hematopoietic tumours. This series cannot conclusively answer the question, whether collision tumours or TTM are more than a random coincidence, but considering our comparably short time window for analysis and the focus on only one institution, there might be evidence for an underestimation of the phenomenon. Either way, diagnosis of such a combined tumour leads to relevant therapeutic consequences, which may largely contribute to the patient’s long-term prognosis and treatment.