The Perinatal Center, 3196 S. Maryland Parkway, Suite 209, Las Vegas, NV  89109, USA

Synonyms:  Brain heterotopia, cystic temporofacial brain heterotopia.

Definition:  Heterotopic tissue consists of histologically normal tissue that is situated in an abnormal location.  Brain heterotopia is a rare developmental anomaly that has been reported to occur in the pharynx, orbit, nasal cavity and maxillofacial region[1].   The lesion is attributed to early displacement of pluripotential cells and cyst formation may result from cerebrospinal fluid production by the choroid plexus-like structures[2].

Introduction:  Large cystic masses in the facial and neck region are rare lesions found prenatally by ultrasound.   We present an unusual case of a cystic lesion in the left mandibular/auricular region on an obstetric ultrasound at 16 weeks gestation.

Case report:  A 34-year old primigravida woman was referred to our center for evaluation of a possible cystic hygroma.  The patient’s family history was negative for congenital anomalies.  Sonography revealed a 21-week fetus whose size was consistent with dates based on a prior ultrasound.  A large cystic structure measuring 79 x 87 mm arising from the left mandibular/auricular area was identified.  The walls were thickened.  There was glandular-appearing tissue with echogenic foci noted at the margins, which most likely represented calcifications.  The mass did not contain any septations.  Color flow Doppler did not reveal any blood flow within the mass.  At the level of the cervical spine, the midline soft tissue structures were displaced toward the right side.  The mass appeared separate from the thyroid or esophagus.  No dilatation of the esophagus was present.  Polyhydramnios was identified with an amniotic fluid index of 243 mm.

 

A follow up ultrasound examination was performed two weeks later and the mass had increased to 100 x 95 mm and the amniotic fluid index had increased to 316 mm.  An amniocentesis, amniotic fluid drainage and fetal neck mass aspiration were then performed. The karyotype revealed 46XY, male chromosome complement, 650 cc’s of amniotic fluid was drained and 350 cc’s of thick brown fluid was aspirated from the neck mass with a sample sent for cytology and chemistry.  The mass measured 133 mm after the drainage.  The post-procedure amniotic fluid index was 170 mm.  Pathology results reported the fluid aspirated from the cyst to contain fetal red blood cells and mononuclear cells-both histocytes and lymphocytes.   Cystic hygroma was suggested as a differential diagnosis.

 

Aspiration needle in the cyst

Collapsed cyst

Within one week the mass had increased to its pre-drainage size and the amniotic fluid index had increased to 259 mm.  The patient was placed on Indomethacin for treatment of polyhydramnios. 

At 25 weeks gestation a second amniotic fluid drainage was performed and 795 cc’s of amniotic fluid was drained.    A shunt was placed into to neck mass and 445 cc’s of fluid was aspirated from the cyst.  A pigtail catheter was inserted into the cyst to allow continuous drainage. 

 

Pigtail catheter inserted in the cyst 

Weekly ultrasound monitoring continued and by 29 weeks gestation a third amniotic fluid drainage of 840 cc’s was performed.  The mass had again enlarged and 300 cc’s of fluid was drained.  At 30 weeks 4 days gestation, a second shunt was placed in the mass since it had again enlarged, and the first shunt was assumed not to drain.  The mass measured 110 x 100 x 90 mm before the drainage and shunt placement, and 83 x 100 x 105 after the procedure.   A fourth amniotic fluid drainage of 1200 cc’s was also performed.  Weekly ultrasound monitoring of amniotic fluid, mass size and Doppler of ductus arteriosus continued.  After one week the amniotic fluid index remained normal and the mass was unchanged in size.  One week later, the amniotic fluid index was normal, but the shunt was seen completely within the mass. 

 

At 33 weeks 5 days the patient was admitted to the hospital with preterm labor and spontaneous rupture of membranes.   Fetal lung maturity amniocentesis was negative.  Patient was placed on tocolytics for another week.  At 34 weeks 5 days a repeat lung maturity amniocentesis was performed and 600 cc’s of fluid was drained from the mass.  Because the foam stability index was 48 (mature) and the fetus developed recurrent late heart rate decelerations, a cesarean section was performed and a 2.77 kg baby boy was delivered.

The newborn

Post surgery

 

 

Followup images at 1 year 2 months and 2 years 3 months of age

Management:  Prenatally, percutaneous drainage of the mass was performed five times to facilitate fetal swallowing.  Shunt placements were attempted on two separate occasions but were not successful.  Amniotic fluid drainage was performed on four occasions to treat polyhydramnios, which was causing preterm labor.  Indomethacin was also used in an attempt to treat the polyhydramnios.   Cystic hygroma was suggested as a differential.  

Postnatally: Two days after delivery the mass had to be drained to relieve airway obstruction.  Computerized tomography and magnetic resonance imaging scans showed a complex cystic mass of the left face and neck with some compression of the oropharyngeal airway.  On day 9 of life, the child went to surgery and the mass was excised along with the left parotid gland and submandibular gland.  The pathology report defined the mass as heterotopic brain tissue, and was confirmed by Children’s Hospital of Philadelphia and UCLA.

Postoperative condition:  Paresis of the left facial nerve distribution, both upper and lower components, resultant in inability to nipple feed and lagophthalmos.  Gastrostomy tube was placed on day 37.  The baby had difficulty tolerating extubation and bronchoscopy was performed on day 37, which showed an abnormally shaped and deficient cartilage formation of the epiglottis.  Because of the tenuous airway, a tracheostomy was performed.  The left ear was somewhat deformed externally with partial occlusion of the external auditory canal.  The brain appeared normal on computerized tomography scan and other than the facial nerve paresis, the baby had a fairly normal neurologic exam upon discharge.

Prevalence:  Fewer than 20 cases of large heterotopic brain tissue in the neck region have been reported[3].

Etiology and pathogenesis:  The etiology of cystic masses of heterotopic brain tissue is thought to be attributable to the early displacement of pluripotential cells and cyst formation may result from cerebrospinal fluid production by contained choroid plexus[4]. Other theories exist regarding the origin of heterotopia.  One such theory suggests that it is derived from an encephalocele that has lost its connection to the subarachnoid space.  Another theory hypothesizes that neuroectodermal tissue develops from multipotent cells during embryogenesis[5].

Differential diagnosis:  Cystic hygromas, encephaloceles, meningoceles, teratomas and brachial cleft cysts[4].

Prognosis:  Good with antenatal intervention and postnatal surgical excision for extracranial lesions.

Treatment:  Complete surgical excision/resection is indicated.  Drainage of the cyst results in reaccumulation of fluid[5].

Follow up:  Plastic surgery, gastroenterology, neurology, ophthalmology and cardiorespiratory follow up arranged after discharge from the neonatal unit.

Reviewers: Aleksandra Novakov, MD, Leif Penrose BA, RDMS, RVT, RT

References:

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These are the only extra references i found in Medline:

Scheiner AJ, Frayer WC, Rorke LB, Heher K.Ectopic brain tissue in the orbit. Eye 1999 Apr;13 ( Pt 2):251-4

Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia 19104, USA.
PURPOSE: The authors report findings in a 9-month-old male infant with heterotopic brain tissue in the orbit, and compare and contrast the characteristics in this patient with the few other descriptions of such lesions in the literature. METHODS: Excisional biopsy of the growth was undertaken by means of an anterior orbitotomy. RESULTS: A 9-month-old male infant had a history of congenital left "anophthalmia" and a slowly growing mass in the left orbit. An MRI scan revealed an orbital mass with solid and cystic components. Histological study of the excised tissue was performed and revealed a choristomatous arrangement of dysplastic brain tissue with intermixed primitive retina including pigmented epithelium. There was no connection between the orbit and cranial cavity. CONCLUSIONS: The mass must be considered a rare example of heterotopic brain tissue in the orbit and is the only instance we could find in the literature in which a formed eye was absent but in which a scattered primitive ocular structure could be identified.

April MM, Seymour BT, Duboys E, Egnor M, Braun A, Katz AE. Massive cystic heterotopic brain tissue. Int J Pediatr Otorhinolaryngol 1994 Jan;28(2-3):235-9
Department of Surgery, SUNY-Stony Brook 11733.
The differential diagnosis of large cystic masses in the newborn should include heterotopic brain tissue. This lesion is attributed to early displacement of pluripotential cells and cyst formation may result from cerebrospinal fluid production by choroid plexus-like structures. Treatment consists of surgical excision.

Hendrickson M, Faye-Petersen O, Johnson DG.  Cystic and solid heterotopic brain in the face and neck: a review and report of an unusual case.  J Pediatr Surg 1990 Jul;25(7):766-8
Primary Children"s Medical Center, Salt Lake City, UT 84113-1100.
An unusual case of heterotopic brain tissue was confused as a lymphangioma in the neck. Although these lesions are rare, they should be included in the differential diagnosis of congenital head and neck masses. They can compress and deform surrounding structures and cause airway obstruction in the newborn. Excision is curative, but the possibility of encephalocele should be eliminated by prior computed tomography scan.

al-Nafussi A, Hancock K, Sommerlad B, Carder PJ.Heterotopic brain presenting as a cystic mass of the palate. Histopathology 1990 Jul;17(1):81-4
Department of Pathology, University of Edinburgh, UK.
We report a case of heterotopic brain which presented as a cystic mass in the palate and which clinically was thought to be a cystic hygroma. Histologically, there was a remarkable proliferation of choroid plexus-like structures which we believe to have been responsible for the production of cerebrospinal fluid. We believe heterotopic brain to result from early displacement of multipotential cells and that the presence of cerebrospinal fluid within extracranial brain tissue does not imply an intracranial communication.

Wilkins RB, Hofmann RJ, Byrd WA, Font RL. Heterotopic brain tissue in the orbit. Arch Ophthalmol 1987 Mar;105(3):390-2
A 3-month-old female infant with Turner"s syndrome was noted to have progressive swelling of the left upper lid at the age of 1 month. A computed tomogram demonstrated a well-circumscribed, low-density, homogeneous orbital mass. Initially, the main clinical differential diagnosis included dermoid cyst, hemangioma, and encephalocele. Medial orbitotomy followed by histopathologic examination disclosed a cystic choristomatous malformation containing brain tissue. No choroid plexuses within the mass were demonstrated on microscopic examination. Aspiration of fluid from the cystic mass and subsequent biochemical studies unequivocally demonstrated that the mass was filled with cerebrospinal fluid. Despite five surgical procedures, including two frontal craniotomies, and specialized roentgenographic studies, no communication could be demonstrated between the orbital mass and the central nervous system. We postulate that the cerebrospinal fluid was produced within the orbital mass, which represented ectopic brain tissue. Problems in diagnosis and management of this unusual orbital malformation are discussed.

Misra BK, Shaw JF, Gordon A. Heterotopic brain cyst from middle cranial fossa to submandibular region. Childs Nerv Syst 1987;3(5):297-300
University Department of Surgical Neurology, Edinburgh University, Western General Hospital, UK.
The case of a newborn boy with a congenital cystic neck mass causing respiratory distress is reported. This lesion extended from the submandibular region through a bone defect to the middle cranial fossa but remained totally extradural. There was no underlying brain abnormality. The cyst was composed mainly of mature neuroglial tissue, with some ependymal and choroid plexus elements, and was diagnosed as heterotopic brain. After 8 years" follow-up, the child still has no deficits.

Patterson K, Kapur S, Chandra RS. "Nasal gliomas" and related brain heterotopias: a pathologist"s perspective. Pediatr Pathol 1986;5(3-4):353-62
Brain heterotopias are rare congenital malformations embryologically related to encephaloceles. They present as a mass in or about the nose (nasal glioma) or in the nasopharynx. We present the clinical and pathological features of 5 cases of heterotopic brain tissue. Four nasal gliomas consisted of mature neuroglial tissue, including neurons in 2 cases, embedded in a fibrovascular stroma. A nasopharyngeal brain heterotopia showed histologic features of mature neuroglial tissue including neurons and ependymal-lined cystic structures. The finding of mature neuroglial tissue in a mass from the head and neck region raises three differential diagnostic possibilities: teratoma, encephalocele, or heterotopic tissue. A teratoma can be ruled out by examination of the entire specimen. Encephaloceles and brain heterotopias can be distinguished only after correlation with the patient"s clinical and radiologic findings.