A 45 yr old female complains of progressive lower limb weakness, spasticity, urinary hesitancy. MRI shows intradural enhancing mass lesion. Most likely diagnosis is –
**Core Concept**
The patient's symptoms and MRI findings suggest a diagnosis of a spinal cord tumor, specifically an intradural extramedullary mass lesion. Intradural lesions arise within the dural sac, and extramedullary lesions are located outside the spinal cord itself. This distinction is crucial for determining the likely origin and behavior of the tumor.
**Why the Correct Answer is Right**
The patient's symptoms of progressive lower limb weakness, spasticity, and urinary hesitancy are consistent with a spinal cord lesion compressing or infiltrating the spinal cord. The MRI finding of an intradural enhancing mass lesion suggests a tumor with a blood-brain barrier, which is typical of meningiomas. Meningiomas are benign tumors arising from the arachnoid cap cells surrounding the spinal cord. They are often slow-growing and can cause symptoms by compressing the spinal cord.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because astrocytomas are more likely to be intramedullary tumors, arising within the spinal cord itself. While they can cause similar symptoms, the MRI finding of an intradural mass lesion is less typical.
**Option B:** This option is incorrect because schwannomas are typically intradural extramedullary tumors as well, but they often arise from the nerve roots and are associated with neurofibromatosis type 2. The patient's symptoms and MRI findings do not strongly suggest a schwannoma.
**Option C:** This option is incorrect because ependymomas are more likely to be intramedullary tumors, arising within the spinal cord itself. While they can cause similar symptoms, the MRI finding of an intradural mass lesion is less typical.
**Clinical Pearl / High-Yield Fact**
When encountering a spinal cord tumor, remember the "ABC" rule: Arachnoid (meningiomas), Blood-brain barrier (intradural lesions), and Compression (symptoms due to spinal cord compression). This mnemonic can help you distinguish between different types of spinal cord tumors and guide your differential diagnosis.
**Correct Answer: D. Meningioma**