Terminal myelocystocele (TMC) and dermal sinus tract (DST) are uncommon forms of skin-covered spinal dysraphism, each arising from distinct embryological mechanisms. The objective of this report is to present, for the first time in the literature to our knowledge, the clinical features, diagnostic evaluation, surgical management, and detailed imaging description of this uncommon association. We present the case of a female neonate with concomitant TMC and DST. Magnetic resonance imaging demonstrated a trumpet-shaped TMC associated with sacral osseous dysraphism and a DST extending from C7-T1 to the skin surface. Both malformations were surgically treated in a single session. The malformed distal neural tissue of the TMC was resected, and the DST was excised completely. Postoperatively, the patient developed a transient lumbar cerebrospinal fluid leak, which resolved with conservative management, and she remained neurologically intact at discharge. Histopathology confirmed malformed neural proliferation in the TMC and squamous-lined tract tissue in the DST. From an embryological perspective, the dual occurrence of TMC and DST highlights that neural tube formation can be disrupted at different stages of development in the same individual. Timely diagnosis and surgical management are critical to prevent complications. Addressing both anomalies in a single operative setting proved feasible and yielded a favorable short-term outcome. Further studies are needed to elucidate the intricate mechanisms involved.

To describe prenatal imaging findings and postnatal outcomes in fetuses diagnosed with saccular forms of closed spinal dysraphism (CSD). This retrospective single-centre study included fetuses diagnosed with non-genetic, non-syndromic CSD between January 2018 and June 2023. Prenatal ultrasound and MRI findings were reviewed, with postnatal outcomes assessed in those managed expectantly, focusing on neurosurgical interventions, motor function, and urologic and bowel outcomes. Eighteen cases were identified; twelve opted for expectant management and had postnatal follow-up. The most common lesion was dysraphic spinal cord lipoma (10/18, 55.6%), followed by limited dorsal myeloschisis (3/18, 16.7%), myelocystocele (3/18, 16.7%) and meningocele (2/18, 11.0%). Chiari malformation and related brain abnormalities were absent at the time of diagnosis in all cases. Most fetuses (88.9%, 16/18) had a low-lying conus medullaris, and 70.6% (12/17) had a sac wall thickness ≥ 2 mm. Postnatally, 75% (9/12) underwent surgical detethering. At ≥ 30 months, all children could walk independently with or without orthoses. However, urologic complications were common in children age ≥ 48 months: 80% (4/5) required clean intermittent catheterization (CIC), 60% (3/5) had urinary incontinence, and 40% (2/5) experienced bowel incontinence. Prenatal imaging features at the lesion level are key for diagnosing CSD. While motor outcomes are favorable, urologic and bowel dysfunctions are frequent in postnatal life.

Lumbar (non-terminal) myelocystocele is a rare form of closed spinal dysraphism which is characterized by posterior bony defect [1-3], a herniated segment of the spinal cord associated with cystic dilatation of the central canal [1-3], and surrounded by cyst filled with CSF in the subarachnoid space i.e. cyst-within-a-cyst. [1-4] The mass is covered by intact skin and variable amounts of subcutaneous fat which is often attached to neural tissue. [1-3] Surgery is advocated to untether the cord and reconstruct the neural tube which will prevent further neurological deterioration. [1-3] In this video, we present the case of a 7-month-old boy who was presented with skin skin-covered lumbar mass after birth. He had left foot drop with no movement in the toes and right foot inversion with associated weakness in the toes. There were no developmental delays and he did not have anorectal anomalies. Magnetic Resonance Imaging (MRI) spine confirmed the diagnosis of lumbar myelocystocele, and urinary flow studies showed good bladder capacity with reasonable voids. The patient underwent spinal cord untethering, neurulation of the neural placode, and duraplasty with an artificial dural graft to increase the cord-sac ratio. [5-7] Postoperative motor power was similar to baseline. The urinary catheter was removed three weeks after surgery with adequate voiding. The were no concerns related to the wound. The parents consented to the procedure and the publication of the patient's video. Institutional Review Board approval was not required.

Terminal myelocystocele (TMC) is rare form of closed neural tube defect (NTD), accounting for approximately 4-8% of occult spinal dysraphisms. It is defined by cystic dilatation of the distal central canal herniating through a posterior spina bifida, typically covered by intact skin. Frequently associated with multisystem malformations, its pathogenesis remains debated, with theories involving disordered secondary neurulation, abnormal cerebrospinal fluid (CSF) dynamics, and failed disjunction between ectodermal layers. We present the case of a male neonate with a lumbosacral mass identified at birth. Magnetic resonance imaging (MRI) revealed a 50 mm TMC associated with a separate meningocele, syringomyelia, scoliosis, butterfly vertebra, and Chiari II malformation. Surgical correction at 2 weeks of age included detethering of the spinal cord, partial cyst wall resection, and dural patch closure under intraoperative neurophysiological monitoring. The postoperative course was uneventful, and at 3-month follow-up the patient remained neurologically stable with normal developmental milestones. This case underscores the clinical and radiological hallmarks of TMC, as well as the importance of early surgical intervention to prevent progressive neurological deterioration. MRI remains the diagnostic gold standard and guides surgical planning. We introduce a novel hypothesis drawing parallels with Chiari malformations, suggesting that fibrous bands and altered CSF hydrodynamics may contribute to cyst enlargement and clinical decline. A multidisciplinary approach and improved understanding of these mechanisms are crucial to optimize outcomes and refine management strategies.