A 22 year old primipara delivered a female child with clinically evident atretic lumbar meningocele and dermal sinus. Slight anterior bowing of both legs was seen.
The child was delivered at 37 weeks by caesarean section in our hospital. Birth weight of the child was 2200 grams. Immediate post delivery examination by the pediatrician revealed an approximately 3x2cm sized cigar shaped protrusion from lower midline back with slightly reddish pink to purple in color which diagnosed to be an atretic meningocele [Fig 1]. An associated area of blind dermal sinus was also evident just caudal to it. Apart from this only slight bending of both legs could be identified clinically. Otherwise the newborn was active and no other obvious anomaly could be detected. Ultrasound of skull, abdomen and plain radiographs of the spine were unremarkable. Radiographs of the lower legs revealed bilateral absent fibula with mild anterior bowing of both tibia. [Fig 2] and [Fig3]. The 4th and 5th ray were also absent.
The family history was negative. Mother had no post-partum illness. The parents belong to lower socio-economic group. No antenatal check up or USG was done. No history of illness or drug intake during pregnancy.
Though absent fibula is a recognized congenital anomaly, however association with other anomalies, especially with meningocele is not very common. The normal incidence of meningocele in general population is 1 per 10,000 live births.Dermal sinus (blind) is another uncommon association in this case. Congenital absence of fibula may present as an isolated anomaly or in association with other anomalies. The fibular hypoplasia is more common in male. Fibular hemimelia is a spectrum of disease from mild fibular hypoplasia to fibular aplasia. The ipsilateral tibia may be hypoplastic, bowed or normal . Fibular hemimelia can be frequently associated with proximal focal femoral deficiency, deficiencies of the lateral aspect of the foot, or is part of a malformation syndrome .The diagnosis is made by the absence of the fibula with commonly associated clubfoot . The disease is usually sporadic, although a familial incidence (autosomal recessive) has been reported in a small percentage of cases .Generally, three types of congenital absence of fibula have been recognized .TYPE I: Includes cases with unilateral or partial absence of the fibula, with mild or no bowing of the tibia (10% of the cases). The leg may or may not be shortened. TYPE II: Patients have unilateral absence of the fibula, anterior “bowing of the tibia with dimpling foot deformity with absent rays” and marked shortening of the leg. This form is observed in about 35% of the cases. TYPE III: The remaining 55% of the patients have unilateral or bilateral absence of the fibula, with the some leg and foot deformities above described and multiple other skeletal defects. The present case is a type III pattern. Apart from meningocele and dermal sinus, the major findings in the present case are absent fibula, bowing of tibia and absent 4th and 5th ray bilaterally. So these findings may represent fibular aplasia-tibial campomelia-oligosyndactyly (FATCO) syndrome.
The most common associated anomaly is proximal femoral deficiency syndrome . Other anomalies include: Cardiac anomalies, thrombocytopenia absent-radius (TAR) syndrome, thoraco-abdominal schisis, spina bifida, renal anomalies .
Agenesis of fibula with meningocele
1. On bilateral lower extremity X-rays, both fibulae are absent or show significant underdevelopment.
2. The tibia demonstrates an anterior bowing deformity (arched change), with a clear outline but abnormal shape, suggesting local developmental or structural abnormalities of the tibia.
3. The foot shows absence of the 4th and 5th toes (or corresponding metatarsals/phalanges), presenting as missing structures in the corresponding toes and metatarsals.
4. Imaging of the lumbar spine shows a localized protrusion behind the spinal canal, which, in combination with clinical findings, suggests a spinal canal–related malformation or meningocele (consistent with the clinically observed spinal canal skin sinus tract and meningeal protrusion).
5. Soft tissue structures appear generally clear, with no apparent fracture lines or other obvious signs of soft tissue masses.
Based on the patient’s fibular absence, tibial bowing, lack of lateral rays in the foot, and accompanying congenital spinal abnormalities, FATCO Syndrome is particularly important in the differential diagnosis. Other possibilities, such as isolated fibrous dysplasia or other congenital skeletal anomalies, usually do not present such definite and extensive lower limb absence coupled with spinal canal–related abnormalities.
Considering the patient’s age, clinical presentation (lumbar dura protrusion, skin sinus tract, bilateral fibular absence, anterior bowing of the tibia, missing lateral rays of the foot, etc.) and imaging characteristics, the most likely diagnosis is: FATCO Syndrome (Fibular Aplasia, Tibial Campomelia, Oligosyndactyly) with a concurrent congenital spinal neural tube defect (e.g., meningocele, skin sinus tract).
1. Multidisciplinary Assessment and Intervention
- Neurosurgery/Spinal Surgery: Evaluate the extent of spinal nerve involvement in the lumbar meningocele and skin sinus tract. If there is a cerebrospinal fluid leak or signs of neurological damage, consider surgical repair to prevent infection or further neurological deterioration.
- Orthopedics: For bilateral lower limb deformities (fibular absence, tibial anterior bowing, foot ray absence), develop an individualized correction plan based on limb development, such as bracing, osteotomy correction, soft tissue surgery, or long-term reconstructive procedures, aiming to optimize gait function and limb length.
2. Conservative Treatment and Support
- For significant tibial bowing with instability, consider bracing or casting.
- For foot deformities, early physical therapy can help preserve joint range of motion and reduce the risk of progressive deformities.
- If the child has limited lower limb mobility or poor muscle strength, use assistive devices (e.g., walkers, orthotic insoles), while monitoring and adjusting them as the child grows.
3. Rehabilitation/Exercise Prescription (FITT-VP Principle)
Disclaimer: This report is based on an analysis of the provided imaging and clinical data, and is for reference only. It is not a substitute for an in-person consultation or professional medical advice regarding diagnosis and treatment. If you have any questions, please consult with orthopedics, neurosurgery, or other relevant specialists promptly.
Agenesis of fibula with meningocele
