Can memory loss, forgetting tasks at work, and tingling in the legs, arms, and back in a working-age adult be indicative of a brain tumor or other neurological condition, such as multiple sclerosis (MS) or peripheral neuropathy (PN)?

Differential Diagnosis: These Symptoms Are Unlikely to Be a Brain Tumor

Your constellation of memory loss, work-related forgetfulness, and tingling in the extremities and back is far more consistent with multiple sclerosis, peripheral neuropathy, vitamin B12 deficiency, or early cognitive impairment than with a brain tumor. Brain tumors typically present with focal neurological deficits, headaches, seizures, or personality changes rather than this diffuse pattern of cognitive and sensory symptoms 1.

Why Brain Tumor Is Low on the Differential

• Brain tumors rarely cause isolated memory problems combined with widespread peripheral tingling. When primary CNS tumors do cause cognitive symptoms, they typically present with attention and executive dysfunction rather than pure memory loss, and these occur alongside other focal neurological signs 2.

• The pattern of "tingling in legs, arms, and back" suggests peripheral nervous system involvement or spinal cord pathology, not the focal cortical dysfunction expected from a brain tumor 2.

• Multiple sclerosis can mimic brain tumor presentations but is far more common in working-age adults and characteristically causes both cognitive symptoms and sensory disturbances in multiple limbs 3.

More Likely Diagnostic Considerations

Multiple Sclerosis (MS)

• MS commonly presents in working-age adults with both cognitive impairment (memory, attention, executive function) and sensory symptoms including tingling and numbness in multiple extremities 3.
• The combination of cognitive and widespread sensory symptoms in a younger adult should prompt consideration of demyelinating disease 3.

Peripheral Neuropathy with Concurrent Cognitive Issues

• Chemotherapy-induced peripheral neuropathy causes numbness and tingling in hands and feet and can interfere with work performance, though this requires cancer treatment history 2.
• Metabolic causes (diabetes, B12 deficiency, thyroid disease) can produce both peripheral neuropathy and cognitive symptoms 4, 5.

Early Cognitive Impairment (MCI or Early Dementia)

• Memory loss and forgetting tasks at work are classic presentations of mild cognitive impairment, particularly when affecting instrumental activities of daily living like work performance 2, 4, 5.
• Patients often use vague terms like "memory loss" when actually experiencing word-finding difficulty, inattention, or difficulty with step-by-step tasks 2, 1.

Essential Immediate Workup

History Taking Priorities

• Obtain history from both you and a knowledgeable informant (spouse, close family member, coworker) separately, as patients with cognitive impairment often lack insight into their deficits 1, 4, 5.
• Document the temporal profile carefully: When did symptoms start? Are they progressive or episodic? Have they worsened over weeks, months, or years? 1.
• Clarify what "memory loss" actually means by asking for specific examples—is it forgetting recent conversations, missing appointments, difficulty learning new information, or word-finding problems? 2, 1.

Objective Cognitive Testing

• Administer the Montreal Cognitive Assessment (MoCA) immediately to detect mild cognitive impairment across multiple domains including memory, attention, and executive function 4, 5.
• Assess functional impact on work: Are you missing deadlines, forgetting meetings, making errors you wouldn't have made before, or having difficulty with complex tasks? 1, 4.

Laboratory Evaluation

• Order complete blood count, comprehensive metabolic panel, thyroid function (TSH, free T4), vitamin B12 with homocysteine, and HbA1c to exclude reversible metabolic causes of both cognitive and neurological symptoms 4, 5.
• Consider HIV testing if risk factors present 5.

Neuroimaging

• Brain MRI is preferred over CT to evaluate for demyelinating lesions (MS), vascular disease, structural abnormalities, or the unlikely possibility of a mass lesion 4, 5.
• MRI is particularly important given the combination of cognitive and sensory symptoms, which could indicate MS or other CNS pathology 1, 5.

Critical Next Steps

If Cognitive Testing Shows Impairment

• Refer to neurology or a memory disorders specialist for comprehensive evaluation 4.
• Schedule follow-up cognitive assessment in 6 months using the same instrument to determine if you're declining, stable, or improving 4.

If Sensory Symptoms Predominate

• Nerve conduction studies and EMG may be needed to characterize peripheral neuropathy if present.
• Spinal MRI should be considered if the "tingling in back" suggests possible spinal cord involvement.

If MRI Shows Demyelinating Lesions

• Lumbar puncture for oligoclonal bands and CSF analysis would be the next step to confirm MS 3.

Common Pitfalls to Avoid

• Don't attribute these symptoms to "normal aging" or stress without proper evaluation, as changes that may be common are not always normal and warrant diagnostic workup 1, 5.
• Don't rely solely on your own report of symptoms when cognitive impairment may be present—informant input is critical 1, 4, 5.
• Don't assume a single unifying diagnosis—you may have two concurrent processes (e.g., early cognitive impairment plus diabetic neuropathy) 5.
• Don't delay evaluation because symptoms seem mild—early detection of conditions like MS or MCI allows for earlier intervention and better outcomes 4.