====== Skull Base Enchondroma ======

[[Maffucci syndrome]] (MS) and [[Ollier disease]] (OD) are rare diseases characterized by multiple benign [[enchondroma]]s. Incidence of skull base (SB) enchondromas and the risk of malignant transformation remain unknown. Most SB lesions are asymptomatic and surgical resection carries significant morbidity. Observation may be a reasonable strategy. We report our experience with observation of probable SB enchondromas in MS/OD patients.

Retrospective review of OD/MS cases with cranial imaging between 1995-2018 at one institution.

14 patients were included-3 MS (21.4%) and 11 OD (78.6%). Median age was 28 years (range 11-74) and 57.1% were female. Extracranial chondrosarcoma was reported in 3 (21.4%) patients. Seven (50%) patients with SB enchondroma or chondrosarcoma were identified on initial imaging. In patients with SB lesions, the indications for imaging were: headache (n=3), seizure (n=1), and diplopia (n=1); 2 cases were incidental findings. Most commonly involved structures: petroclival fissure (86%) and clivus (71%). Treatment included observation (6/7) and resection (1/7). Follow-up imaging was available for all SB lesions with a mean interval of 50.7 months (range 5-225) and was negative for progression in all cases.

Primary SB lesions in OD/MS patients frequently present in the petroclival junction. Cranial screening and close observation should be considered in MS/OD patients given increased risk of intra-axial intracranial tumors, de novo chondrosarcomas or malignant degeneration of previously known lesions. In asymptomatic patients, observation appears to be a safe strategy in this cohort. Further case accumulation and follow-up is required to better understand the long-term outcomes
((Oushy S, Peris-Celda M, Van Gompel JJ. Skull Base Enchondroma and
Chondrosarcoma in Ollier Disease and Maffucci Syndrome. World Neurosurg. 2019 Jun
21. pii: S1878-8750(19)31639-0. doi: 10.1016/j.wneu.2019.06.087. [Epub ahead of
print] PubMed PMID: 31233929.
)).

===== Case reports =====

Enchondroma of the Skull Base in a Case of Ollier's Syndrome
((Sabeti S, Yousefi F, Pourabdollah Toutkaboni M. Enchondroma of the Skull Base 
in a Case of Ollier's Syndrome. Iran J Pathol. 2015 Summer;10(3):237-42. PubMed
PMID: 26351491; PubMed Central PMCID: PMC4539773.
)).