Dear Editor, We present the first case, to our knowledge, of a myolipoma diagnosed in adulthood in the context of a complex sacral malformation. Myolipoma with intradural location is a very rare occurrence in neurosurgical pathology. Although previously reported, the number of cases is scarce and all are in patients younger than 18 years old. A 26-year-old male presented with a neurological history starting in childhood with micturition urgency. At 16 he started to notice slight muscle wasting in the lower left leg. Two years prior to presentation, he began to notice sensitive andmotor paresis in the lower limbs. The onset of paresthesias in the upper limbs determined his presentation. He denied any bowel difficulties or associated medical problems. Physical examination showed atrophy of the gastrocnemius muscle in the left lower limb and a 5-cm-long pseudotail at coccygeal level. Neurological exam showed decreased superficial sensitivity on the distal lateral part of the foot and in the 4th and 5th toes. Motor exam showed hypertonia in the right leg with bilateral hyperreflexia for both knee and ankle jerks. Rectal tone and sensitivity were normal. Brain, cervical and dorsal spine MRI were normal. At the S3–S5 level, it revealed a mass of 42 cm, isoto hyperintense on T2-weighted images, with a low-lying conus and tethered spinal cord, an anterior cystic dilation of the dural sac with subjacent thinning of the sacral wall (Fig. 1a, b, c). Both planar CT and 3D reconstructions documented a closure defect of the posterior sacral wall at the S4–S5 level and the significant erosion of the anterior wall (Fig. 1d). Surgery consisted of microsurgical removal of the tumor using ultrasonic aspiration and intraoperative electrophysiological monitoring (free-running and triggered EMG of the external anal sphincter, anterior tibialis, and abductor hallucis longus bilaterally). The dura appeared normal, yet caudally it was contiguous with the posterior aspect of the inferior half of the tumor. All areas with a positive electrophysiological signal have been preserved. A small part of the tumor was left in place as it formed a highly adherent mass containing nervous structures. The thickened filum was sectioned at the S5 level and disconnected from the sacral fat. Histological examination revealed the presence of mature striated muscle mixed with fat cells with areas of smooth muscle fibers (Fig. 1e, f). The follow-up at 2, 6, and 12 months documented a favorable evolution. Paresthesias in the lower limbs remitted completely. The motor function returned to normal almost completely with a small degree of paresis remaining on the left side. The micturition urgency resolved, following a regular rehabilitation program. A discreet degree of hyperreflexia was still manifest in the left lower limb. MRI at 2 months and 1 year showed no progression of the remnant tumor (Fig. 1g, h). Gowers [5] reported the first case of a spinal myolipoma in 1876. Fivemore cases were reported starting with the paper by Schcergna and Turinese [7] in 1962, and ending with the report of Shimizu et al. [8] in 2013. The last two reports published [2, 8] mention the contraction of the tumor when stimulated electrically intraoperative, a phenomenon we also observed. The patients described in two of the reports (Gowers and Brown) presented with bladder incontinence. Good recovery of bladder function was documented in those patients following resection, as it happened in our case as well. * Bogdan Florin Iliescu bogdan.iliescu@gmail.com