Spinal subependymomas are very rare low-grade tumors (WHO I) of the spinal cord. Like intracranial subependymomas, that are far more common, spinal subependymomas are slow-growing, discrete tumors with little if any contrast enhancement.
Due to the small number of cases reported it is difficult to draw firm epidemiological conclusions. These tumors have been reported in a wide age range (6 to 73 years) without a consistent gender predilection 1,2.
As these tumors are slow-growing, there is usually a fairly lengthy clinical history typically including sensory symptoms, pain, and weakness 2. Spinal subependymomas are most often located within the cervical cord, followed by the thoracic cord 1,2.
Spinal ependymomas present as intramedullary spinal cord tumors with the following features:
- excentric subpial growth (sometimes extensive) 1
- expansion of the affected cord over a short distance: bamboo leaf sign 1
- adjacent syrinx is sometimes present 2
They have similar signal intensity characteristics as intracranial subependymomas 2:
- T1: isointense to cord
- T2: hyperintense to cord
- T1 C+: variable, ranging from nil to prominent
Treatment and prognosis
Treatment, if clinically indicated, is surgical although as these are indolent and slow-growing complete resection is not necessarily required 2.
Other intramedullary spinal cord tumors are all considerations, however, as spinal subependymomas tend to be intramedullary and only relatively well-circumscribed, the main differential to be considered are:
It is difficult to categorically make a preoperative distinction, especially as subependymomas are so much less common than either spinal ependymomas or astrocytomas, however, the absence of significant enhancement, the excentric subpial intramedullary location may serve as clues 1.
- 1. Toi, Hiroyuki, Ogawa, Yukari, Kinoshita, Keita, Hirai, Satoshi, Takai, Hiroki, Hara, Keijiro, Matsushita, Nobuhisa, Matsubara, Shunji, Uno, Masaaki. Bamboo Leaf Sign as a Sensitive Magnetic Resonance Imaging Finding in Spinal Subependymoma: Case Report and Literature Review. (2019) Case Reports in Neurological Medicine. doi:10.1155/2016/9108641
- 2. Yuh WT, Chung CK, Park SH, Kim KJ, Lee SH, Kim KT. Spinal Cord Subependymoma Surgery : A Multi-Institutional Experience. (2018) Journal of Korean Neurosurgical Society. 61 (2): 233-242. doi:10.3340/jkns.2017.0405.001 - Pubmed