Unilateral Limb Thinning -Thinking Out of the Box.

We report an unusual presentation in a 9-year-old girl with unilateral circumferential thinning of the entire right upper limb without any other neurological deficit, with normal nerve conduction and electromyography initially thought of as a neurodegenerative disorder based on clinical presentation. Magnetic resonance imaging of the upper limb showed partial lipoatrophy with normal glucose metabolism and lipid profile and negativity for HIV and autoimmune disease (panniculitis) with no family history of similar disorder. Remember to think out of box before labeling neurodegenerative disease.