Development of an undifferentiated sarcoma following internal carotid artery aneurysm stenting: causality or coincidence? Illustrative case
4 affiliations
- 1Department of Neurosurgery, ASST Ovest Milanese Ospedale di Legnano, Milan Province
- 2Neurosurgery Residency Program, University of Milan, Milan Province
- 3Department of Pathology, ASST Ovest Milanese Ospedale di Legnano, Milan Province
- 4Department of Neuroradiology, Ospedale Niguarda Ca’ Granda, Milan, Milan Province, Italy
Abstract
BACKGROUND: Undifferentiated soft tissue sarcomas are rare tumors lacking identifiable differentiation. Primary sarcomas associated with aneurysm sacs are extremely rare, typically involving large vessels. Intracranial involvement is exceptional and poorly documented.
OBSERVATIONS: The authors report the case of a patient treated in 2009 for a left paraclinoid internal carotid artery aneurysm (18 × 10 mm) by endovascular stenting (Silk 4.5/30). Eleven years later, he developed headache, somnolence, visual blurring, left ptosis, and anisocoria. CT and CTA showed the known thrombosed aneurysm and an adjacent hypervascular midline lesion. Angiography confirmed complete exclusion with a patent stent and no new aneurysms. MRI revealed a suprasellar-retrosellar multilobulated enhancing mass causing marked brainstem compression. Surgery identified a solid lesion seemingly arising along the thrombosed aneurysm sac, and partial resection was performed. The patient initially recovered but subsequently deteriorated with rapid tumor regrowth and died during hospitalization. Histological analysis showed a grade 3 undifferentiated sarcoma (vimentin +, MDM2+, focal smooth muscle actin −, CAM5.2−, GFAP−). Postmortem examination confirmed origin within the aneurysm sac adjacent to the stent.
LESSONS: To the authors’ knowledge, this is the first reported undifferentiated sarcoma arising from a stent-treated carotid aneurysm. Although causality cannot be established, it parallels rare stent-associated sarcomas in large vessels and highlights the diagnostic challenges of atypical masses in treated vessels.
https://thejns.org/doi/10.3171/CASE26659
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BibTeX
@article{scalise2026development,
title = {{Development of an undifferentiated sarcoma following internal carotid artery aneurysm stenting: causality or coincidence? Illustrative case}},
author = {Matteo Scalise and Andrea Cividini and Stefano Peron and Delia Cannizzaro and Paola Rita Billo and Mariangela Piano and Roberto Stefini},
journal = {Journal of Neurosurgery: Case Lessons},
year = {2026},
month = oct,
doi = {10.3171/case26659},
url = {https://doi.org/10.3171/case26659},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Development of an undifferentiated sarcoma following internal carotid artery aneurysm stenting: causality or coincidence? Illustrative case
AU - Matteo Scalise
AU - Andrea Cividini
AU - Stefano Peron
AU - Delia Cannizzaro
AU - Paola Rita Billo
AU - Mariangela Piano
AU - Roberto Stefini
PY - 2026
DA - 2026/10/26
JO - Journal of Neurosurgery: Case Lessons
DO - 10.3171/case26659
UR - https://doi.org/10.3171/case26659
AB - BACKGROUND: Undifferentiated soft tissue sarcomas are rare tumors lacking identifiable differentiation. Primary sarcomas associated with aneurysm sacs are extremely rare, typically involving large vessels. Intracranial involvement is exceptional and poorly documented. OBSERVATIONS: The authors report the case of a patient treated in 2009 for a left paraclinoid internal carotid artery aneurysm (18 × 10 mm) by endovascular stenting (Silk 4.5/30). Eleven years later, he developed headache, somnolence, visual blurring, left ptosis, and anisocoria. CT and CTA showed the known thrombosed aneurysm and an adjacent hypervascular midline lesion. Angiography confirmed complete exclusion with a patent stent and no new aneurysms. MRI revealed a suprasellar-retrosellar multilobulated enhancing mass causing marked brainstem compression. Surgery identified a solid lesion seemingly arising along the thrombosed aneurysm sac, and partial resection was performed. The patient initially recovered but subsequently deteriorated with rapid tumor regrowth and died during hospitalization. Histological analysis showed a grade 3 undifferentiated sarcoma (vimentin +, MDM2+, focal smooth muscle actin −, CAM5.2−, GFAP−). Postmortem examination confirmed origin within the aneurysm sac adjacent to the stent. LESSONS: To the authors’ knowledge, this is the first reported undifferentiated sarcoma arising from a stent-treated carotid aneurysm. Although causality cannot be established, it parallels rare stent-associated sarcomas in large vessels and highlights the diagnostic challenges of atypical masses in treated vessels. https://thejns.org/doi/10.3171/CASE26659
SN - 2694-1902
ER -