Background <p>Lipomyelomeningocele (LMM) is the most common form of closed spinal dysraphism and is typically diagnosed in childhood. Although many patients are initially asymptomatic, progressive neurological deterioration may occur over time due to tethered cord syndrome (TCS). Adult presentation of untreated LMM is rare and poorly described in the literature, and optimal management strategies in this population remain controversial.</p> Case <p>We report the case of a 53-year-old man with a congenital lumbosacral mass and a history of partial superficial lipoma resection in childhood, who presented with progressive sphincter dysfunction, lumbar pain, sexual dysfunction, and neurological decline. His clinical course was marked by long-standing unrecognized neurological impairment, leading to chronic lower extremity ulcerations, recurrent osteomyelitis, and multiple amputations. Magnetic resonance imaging demonstrated a large intra and extradural lumbar lipomyelomeningocele associated with tethered cord syndrome. The patient underwent microsurgical near-total resection of the intradural lipoma, detethering of the neural placode, dorsal neurulation, and expansile duraplasty. Postoperatively, he experienced significant clinical improvement, including recovery of spontaneous urination, reduced need for intermittent catheterization, resolution of neuropathic pain, and improvement in sexual function, without surgical complications.</p> Conclusion <p>This case highlights the potential for severe and irreversible morbidity associated with delayed diagnosis and inadequate long-standing follow-up of lipomyelomeningocele. Although prophylactic surgery remains controversial, timely recognition, close surveillance, and individualized surgical intervention when symptoms arise may improve neurological and functional outcomes in adult patients. Multidisciplinary, long-term follow-up is essential to reduce morbidity and optimize quality of life in this rare but challenging population.</p>