Purpose or Case Report: Chaotic lipomyelomeningocele (cLMM) is an uncommon and poorly understood closed spinal dysraphism characterized by disorganized lipomatous tissue and atypical placode position. While most dysraphisms are detected in infancy, delayed symptom onset may occur, creating diagnostic and management challenges. We present a rare case highlighting the value of high-resolution MRI in late presentation of cLMM and its implications for neurosurgical decision-making.
Methods & Materials: A 7-year-old boy with known spina bifida occulta and previously identified tethered cord presented with progressive bowel dysfunction characterized by chronic diarrhea and fecal urgency. MRI demonstrated a low-lying cord terminating at S1–S2 tethered by a 2.9 × 0.8 cm heterogeneous lesion with macroscopic fat and cystic/solid components. A syrinx extending from T12 to L5–S1 (maximum AP diameter 3 mm) was identified. A 3.5 × 0.8 cm enhancing subcutaneous midline buttock lesion corresponded to an ulcerated hemangioma, serving as a cutaneous marker. No vertebral segmentation anomalies were present.
Results: The evolution from an initially asymptomatic tethered cord to delayed symptomatic presentation with syrinx formation underscored the dynamic course of some dysraphic lesions. The combination of complex tethering anatomy, associated syrinx, and cutaneous marker confirmed chaotic LMM. These imaging findings prompted urgent neurosurgical evaluation for potential untethering to prevent progression of neurologic and sphincter dysfunction.
Conclusions: This case emphasizes that chaotic LMM may manifest clinically beyond infancy, requiring vigilant longitudinal surveillance. MRI provides crucial anatomic detail to differentiate chaotic variants from typical lipomyelomeningoceles, detect secondary changes such as syrinx formation, and guide surgical planning. Recognition of evolving radiologic patterns can directly impact timing of intervention and prevent irreversible deficits.