ADELOYE-ODEKU DISEASE IN ASEER REGION OF SAUDI ARABIA

Abstract

Adeloye-Odeku disease, also known as congenital inclusion dermoid cyst (CIDC) of the anterior fontanelle was first described in a publication in 1971 by Adeloye A and Odeku EL, as a solitary congenital subgaleal inclusion dermoid cyst of the anterior fontanelle in Nigerians. This rare lesion, (0.1-0.5% of all cranial tumors and 0.2% of all inclusion cysts), was initially thought to be an African cyst. The universal distribution of this cyst has subsequently been shown in accumulated literature of other ethnic distribution, Caucasians, Indians, Chinese, Japanese, Turkish and others. This is the first published report that we know of Adeloye-Odeku disease in Saudi Arab children in Abha, Saudi Arabia. Four patients with Adeloye-Odeku disease, two boys and two girls, Saudi patients with ages ranging from 3months to 9years are presented. All had CT and MRI brain scans. Successful surgical excision of the cyst was achieved in each of the three patients who consented for surgery and there was no recurrence. The parents of the oldest patient declined surgical intervention but agreed to outpatient follow up.

Introduction

Congenital inclusion dermoid cyst (CIDC) of the anterior fontanelle is a rare lesion that is noticed soon after birth in all affected patients as a solitary lesion. It accounts for 0.1-0.5% of all cranial tumors1 and 0.2% of all inclusion cysts2.

Adeloye-Odeku in 1971, were the first authors who published a full description and management of congenital subgaleal cysts over the anterior fontanelle in Nigerians3 and named it Adeloye-Odeku disease. This condition was initially thought to be an African cyst4. World wide occurrence of congenital dermoid cyst of the anterior fontanelle has since been shown in publications5, 6, 9, 10, 11, 12.

CIDC is a developmental anomaly in which displaced dermal elements are included in the neuroaxis along the embryonic fusion line. There is no communication between the cyst and the intracranial contents. The cyst is a slow growing, non tender fluctuant mass covered with intact skin over the anterior fontanelle. The size of the cyst has varied with the age of the patient at the time of diagnosis6 and a measurement range of 1-7cm have been recorded1. The cyst transilluminates. Surgical excision is curative and there is no recurrence. All patients had no associated neurological findings. Other important differential pathologies are encephalocele, meningocele, sebaceous cyst, lipoma, haemangioma and cephalhematoma. Some authors however, have reported inclusion cysts in adults7,8 based on the age of the patient at the time of diagnosis.

Materials and Methods

Between 2004 and 2010, consecutive patients with Adeloye-Odeku disease were prospectively recruited into this study involving Arab-Saudi patients. Four patients with non-tender swellings over the anterior fontanelle were seen in the neurosurgical outpatients department of Aseer Central Hospital, Abha, and the regional referral center of the southwest of the Kingdom of Saudi Arabia.

1) A one and half year old female Saudi patient was admitted from the outpatients’ clinic because the parents wanted cosmetic correction of a small painless scalp swelling in the middle of her head that had failed to disappear since her birth. There was no other complain in this thriving baby girl. Routine blood tests were normal. CT & MRI brain confirmed the cyst, 15x20mm in diameter. It had no intracranial extension. In the operating room under general anesthesia, a complete excision of the cyst was achieved through a coronal scalp incision over the mass and blunt dissection of the cyst from the underlying tissues. Care was taken to avoid injury to the dura and cranium and this enabled this cyst with clear contents to be delivered without capsular rupture. There was no intracranial extension of the cyst. Haemostasis was achieved and a continuous suction drain inserted. Layered closure of the incision was achieved with vicryl and silk to skin. The drain containing 3ml of serum-bloody fluid was removed after 2days. Microscopically, the cyst wall was made up of connective tissue lined by squamous epithelium. In the subepithelial layer were adnexial

appendages like sebaceous glands, sweat glands and hair follicles.

Fluid from the cyst had Protein: 1mg/dl; Glucose: 1mg/dl; potassium: 20.4mmol/l; sodium: 10mmol/l; Urea: 162mg/dl; LDH: 109u/l; Amylase 1u/l. Patient recovered without any complication and the patient’s parents were satisfied with the aesthetic result. Follow up in the outpatients’ clinic in a 2-year period showed no recurrence.

2) A three-month-old male Saudi was admitted for the removal of a small lump occupying the anterior fontanelle noticed after birth. The swelling seemed to be growing slowly with the child, who had no other neurological problem. The dome shaped mass was non-tender and transilluminates light. Pre-operative brain CT scan showed a well-defined extra cranial, subcutaneous fluid-density cyst over the anterior fontanelle. The cyst measured 20x10mm in diameter. CT brain showed normal ventricles with no midline shift or deformity; normal posterior fossa; no areas of recent blood density and no extra collections were seen. MRI of the brain showed a well-defined oval shaped cystic swelling over the anterior fontanelle. It measured 15x10mm in diameter. It had a thin wall, no interval septum or solid masses and had fluid intensity. The rest of the brain was normal. In the operating room under general anesthesia, a complete excision of the cyst was achieved without damage to the underlying midline structures through a skin crease incision and blunt dissection. Haemostasis was achieved and a continuous suction drain left in the sutured wound for 2days after which the drain was removed.

The cyst fluid had clear contents and had Protein: 0.5mg/dl; Glucose: 1mg/dl; potassium: 15mmol/l; sodium: 10mmol/l; Urea: 100mg/dl; LDH: 100u/l; Amylase 1u/l. Histopathology of the cyst wall showed connective tissue lined by stratified squamous epithelium. There were sebaceous glands and hair follicles in the adnexial layer. The patient had an uneventful postoperative period and there was no recurrence during the 2years follow up period.

(3) A one-year-old Saudi girl presented with a swelling over the anterior fontanelle, which was present at birth and did not seem to cause the child any problem but had failed to go away. CT scan brain confirmed a dermoid cyst, 15x20mm in diameter. This cyst was removed under general anesthesia in the operating room through a skin crease incision and careful blunt dissection that avoided injury to the underlying dura mater. A continuous suction drain was left in the sutured wound for 2days after which the drain was removed. The cyst fluid had clear contents and had Protein: 1mg/dl; Glucose: 1mg/dl; potassium: 20.0mmol/l; sodium: 5mmol/l; Urea: 150mg/dl; LDH: 110u/l; Amylase 1.2u/l. Histopathology of the cyst wall showed connective tissue lined by stratified squamous epithelium. No recurrence has been shown in the outpatients follow up of 2years.

(4) A nine-year-old boy presented with a small lump in the middle of the head. This was only noticed a month before presentation because of headaches. He had no fits or vomiting. There was no other neurological deficit.

CT & MRI brain showed an extra cranial small well-defined cyst 20x20mm in the middle of the frontal bone abutting the saggital sinus but separate from the intracranial and the CSF spaces. The brain and the ventricles were normal. This atretic anterior fontanelle cyst was suspected to be a dermoid cyst. Parents of this child declined surgical intervention but agreed to follow up in the outpatients’ clinic for this asymptomatic small suspected dermoid cyst.

Summary

Adeloye-Odeku disease, CDIC, manifested soon after birth in three Saudi patients while the fourth patient’s lesion was an accidental presentation at the age of 9years. The lesion in this latter patient was small, the lack of change in size, was hidden away behind the hairline and did not pose a problem to the boy. There was no gender difference in our study. CT and MR imaging of the brain confirmed the extra cranial position of the cyst and no intracranial extension. The size of the lesion in our study was between 10-20mm, within the range of 10-70mm reported in other studies, (2). Complete surgical excision with no complication or recurrence was achieved in the three patients operated. The asymptomatic nature of this benign small lesion and the no change in size made the parents to opt for follow up in the nine-year-old boy instead of surgical excision.

Discussion

Adeloye-Odeku disease is a rare lesion that has been shown to be worldwide and not African as was initially thought 8. The total number of published cases of congenital dermoid inclusion cyst of the anterior fontanelle in children worldwide in 1989 was 174; Americans were 74, Africans 45, Europeans 30 and others 25⁵. Many other authors have since added to that number in their publications.

A congenital dermoid inclusion cyst (CDIC), of the anterior fontanelle accounts for 0.1-0.5% of all cranial tumors 2 and 0.2% of all inclusion cysts 1. The lesion usually manifests at birth.

A simple plain X-ray of the patient’s skull is a starting radiological investigation. CT scan and magnetic resonance imaging (MRI) of the skull in our 4 patients confirmed these modalities as the most reliable and accurate in delineating the lesion as other authors had found 2,11.

The size of the lesion in our study was between 10-20mm, within the range of 10-70mm reported in other studies 2.

There was no gender difference in our study.

The histology of the cyst in all three cases in our study was the same as findings in published studies and showed squamous epithelium lining and skin appendages like hair follicles, sebaceous and sweat glands in the adnexial layer8,10,1 .

The three operated patients with Adeloye-Odeku disease in our study had clear colourless contents with low proteins, sugar and sodium chloride consistent with published cases9,10,11,12. Variation in the colour of the cyst fluid was found in other studies depending on the size and age of the lesion as well as the contained dermal elements^8,9. Some authors have published cases of anterior fontanelle cyst in adults3,7.

Aesthetic appearance of the patient is the main reason for seeking surgical intervention by parents. Other reasons are bewilderment, anxiety, unawareness, ignorance and fear of the outcome of surgical intervention.

CDIC is a benign lesion that can be easily excised and cured with no recurrence. Excision of the cyst prevents possible rupture and infection and provides tissue for histological diagnosis and to rule out malignancy.

The 4cases presented in this study have added Saudi patients to the worldwide published cases. There was no gender preponderance in our study. Surgical excision achieved an aesthetically satisfactory appearance and no neurological complication. No recurrence has occurred in the follow up period. Histology confirmed dermoid cyst and no malignancy. Follow up in the outpatients clinic for the patient who did not have surgery is going on.