|Year : 2007 | Volume
| Issue : 2 | Page : 75-78
Suprasellar epidermoid presenting with precocious puberty
Nigel Peter Symss, AN Prasad, Ravi Ramamurthi, MC Vasudevan
Post Graduate Institute of Neurological Surgery, Dr. Achanta Lakshmipathi Neurosurgical Centre, Voluntary Health Services Hospital, Chennai - 600 113, India
Nigel Peter Symss
Department of Neurosurgery, Post Graduate Institute of Neurological Surgery, Dr. ALNC, VHS Hospital, IT Corridor, Taramani Road, Chennai - 600 113
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Epidermoids are inclusion tumors of the central nervous system and are rare, benign slow-growing tumors. They are estimated to constitute 0.5-1.8% of the brain tumors and have an affinity for the subarachnoid cisterns at the base of the brain, the suprasellar cistern being one of the most favoured sites. We report a case of suprasellar epidermoid in a 2-year-old male child with an unusual CT and MRI appearance, who presented to us in February 1995 with features of precocious puberty. In October 2004, at the age of 11 years, he presented with symptoms and signs of raised ICP.
Keywords: Epidermoid, precocious puberty, suprasellar cistern
|How to cite this article:|
Symss NP, Prasad A N, Ramamurthi R, Vasudevan M C. Suprasellar epidermoid presenting with precocious puberty. J Pediatr Neurosci 2007;2:75-8
| Introduction|| |
Epidermoids are tumors of disordered embryogenesis and are of congenital origin. They grow very slowly and often reach a large size before becoming symptomatic, commonly in the third and fourth decades of life. Epidermoids in the suprasellar location most commonly produce symptoms referable to the optic apparatus. They can also present with pituitary dysfunction along with the visual symptoms. , On CT scan, the lesion usually appears as a hypodense mass with an attenuation value between -2 to +32 Hounsfield Units . Lesions with a relatively high density between 80 and 120 HU can also occur. , Suprasellar epidermoids presenting with precocious puberty is an uncommon presentation, and the exact incidence is uncertain. We are reporting such a case along with a review of the literature.
| Case History|| |
A 2-year-old male child presented to us in February 1995 with complaints of hoarsening of voice, increased body weight and abnormal increase in the size of the external genitalia with appearance of pubic hair since the age of one year. There was no headache, vomiting, visual disturbances or abnormal increase in size of the head. His weight was 24 kg (expected weight: 15 kg); his external genitalia and testicular volume were of adult size with pubic hair (Tanner grade 3). His fundus examination was normal, and he had no cranial or spinomotor-sensory deficits. His systemic examination was also normal. Plain X-ray of the skull lateral view showed a normal sella with no features of raised ICP. The CT scan of the brain plain study showed a well-circumscribed hypodense lesion in the suprasellar region [Figure - 1]. The MRI scan of the brain showed a lesion in the suprasellar region, which was homogeneously hyperintense in T1- and T2-weighted images with no hydrocephalus [Figure - 2]. The endocrine assays were as follows S.Testosterone - 8 ng/ml (normal 0-0.45 ng/ml prepuberty), S.FSH 14.0 mIU/ml (1-9 mIU/ml prepuberty), S.LH 22.0 mIU/ml (3-15 mIU/ml prepuberty), 17 ketogenic steroids - 6.8 mg/24 h (normal: 5-12.5 mg/24 h), 17-OH steroids - 8.3 mg/24 h (normal: 5-15 mg/24 h). A pterional craniotomy was done. The lesion was seen below and posterior to the chiasm, adherent to the hypothalamus. The capsule of the lesion was whitish, tough and difficult to breach to enter the lesion. There was also an area of calcification. Considering its dense adherence to the hypothalamus, only a biopsy of the lesion was done. The histopathological report was acellular proteinaceous material. He was advised regular follow-up.
The patient reported again in December 1995 with complaints of further development of his secondary sexual characters. A repeat CT scan of the brain plain and contrast study showed a well-defined rounded nonenhancing cystic sellar-suprasellar lesion, and there was no increase in size of the lesion in comparison to the previous scans. Hence, he continued to remain under observation. He returned for follow-up in January 1998 at the age of 6 years with further development of other secondary sexual characters [Figure - 3]. His neurological and systemic examination was normal. The CT scan of the brain was repeated, which showed an increase in the size of the lesion with an attenuation value of - 113 HU [Figure - 4]. There was no hydrocephalus. His S. testosterone level was 400 ng/dl (normal: 0-5 ng/dl), S.FSH levels - 42.0 mIU/ml (normal: 0-2 mIU/ml) and S. LH - 7.0 mIU/ml (normal 0-4 mIU/ml). As he had no neurological deficits, he was started on anti-androgens and was advised regular follow-up. He presented to us in October 2004 at the age of 11 years with complaints of headache, vomiting, blurring of vision, increasing drowsiness and unsteady gait with a duration of 1 week. His fundus examination showed papilledema. He had no other neurological deficits. His height was 165 cm; there was further development of his external genitalia and testicular volume (Tanner grade 4) with complete development of other secondary sexual characters. The CT scan of the brain plain and contrast study showed a well-defined hypodense, nonenhancing sellar-suprasellar lesion extending upto the anterior third ventricle, with an attenuation value of -114 at the centre and -73 at the periphery [Figure - 5]. There was obstructive hydrocephalus. His S. testosterone level was 214 ng/ml (normal: 0-10 ng/ml). Since the lesion was extending upto and distorting the third ventricle, the patient underwent a right midline frontoparietal craniotomy, transcallosal approach and radical excision of the lesion. The lesion had a characteristic pearly appearance of an epidermoid and was flaky in consistency. Postoperatively, he was continued on steroids, but he still developed chemical meningitis that was managed with the lumbar drainage (twice daily) of CSF and antibiotics. Postoperative CT scan showed no residual lesion, and his S. testosterone level dropped to 110 ng/ml.
| Discussion|| |
In 1829, Curveilhier described the epidermoid tumor and named it as "pearly tumor." Intracranial epidermoid cysts constitute 0.5-1.8% of all the intracranial tumors. They are inclusion tumors that arise from displaced midline ectodermal cells between the third and fifth weeks of gestation during the closure of the neural tube when the neural tube separates form the overlying ectoderm along the mid-dorsal aspect of the embryo. Misplaced epithelial rests may be deposited between the neural canal and the skin that may expand into a cyst to form an epidermoid or a dermoid. They have a slow rate of growth, due to which they usually become symptomatic in the third or fourth decade. These tumors have an affinity for the basal cisterns, the suprasellar and CP angle cisterns being the most favoured sites.
The clinical picture of intracranial epidermoids varies according to their location, direction and rate of growth, interference with the CSF pathways and compression of neural and vascular structures. Suprasellar epidermoids most commonly produce symptoms referable to the optic apparatus, such as visual impairment, optic atrophy and bitemporal hemianopia.  Pituitary dysfunction may or may not be evident along with the visual symptoms. , Our patient first presented to us in 1995 at the age of 2 years with precocious puberty, which is an uncommon presentation for suprasellar epidermoids. Precocious puberty in boys is much rarer than in girls and almost invariably secondary to central lesions. A structural CNS lesion can be demonstrated by CT or MRI in 25-75% of boys with central precocious puberty.  The commonest intracranial tumors causing precocious puberty are hamartomas, gliomas, craniopharyngiomas, germinomas, ganglioneuromas, ependymomas, third ventricular cysts and pinealomas.  Other lesions that have been reported to present with precocious puberty are suprasellar arachnoid cysts  and Rathke's cleft cysts.  A suprasellar germ cell tumour involving the anterior portion of the third ventricle presenting with both precocious puberty and diencephalic syndrome has been reported.  Tumors and other pathological lesions involving the hypothalamus frequently modify the sexual development. These lesions may destroy the posterior hypothalamus leaving the anterior hypothalamus intact. The intact anterior hypothalamus, in the absence of inhibitory influences, leads to increased pituitary function. The preoptic region possibly plays an important role in regulating the release of gonadotropic hormones from the anterior lobe of the hypophysis. In rats, this region has been termed as the "sexually dimorphic nucleus of the preoptic area."  Styme stated that an inhibitory tone develops within the central nervous system after birth that reduces the gonadotrophin levels, thereby preventing early pubertal development.  It is postulated that this neural inhibition may be interrupted by hypothalamic hamartomas leading to precocious puberty. This explanation may also hold true for other lesions associated with precocious puberty.
On CT scans, epidermoids usually appear as a hypodense, irregular lesion with an attenuation value between -2 and +32 HU without contrast enhancement or just minimal enhancement may be seen at the periphery. Epidermoids of a relatively high density with 80-120 HU can occur, but they are very rare. , A density in the range of -73 to -114 HU as seen in this patient may be attributed to the high lipid component and cholesterol.  Hydrocephalus is only seen occasionally with epidermoids due to the percolation of CSF through the interstices of the tumour. This is an important differentiating factor between an epidermoid and other tumors that act as obstructive space occupying lesions. On MRI, epidermoids have variable features; the lesions usually appear slightly hyperintense or isointense to the CSF and hypointense to brain on TI-WI, and the lesion is markedly hyperintense relative to brain and slightly hyperintense to CSF in T2-WI images.  Epidermoids with atypical MRI signal patterns have been reported. [15,16] Horowitz et al. reported three cases of epidermoids showing hyperintensity on TI-WI.  All lesions reported to be hyperintense on TI-WI have been cystic rather than solid. ,
The treatment is complete excision of the cyst and its contents. As the lesion was extending upto and distorting the anterior third ventricle, a transcallosal approach and radical excision of the lesion was done. The extent of excision of a lesion depends on its location, anatomical extension, and its relationship to the major neural and vascular structures. In some cases, there may be a clear plane of cleavage between the tumor lining and arachnoid membrane, enabling the total excision of the lesion. In others cases, however, the cyst lining often becomes adherent to neural and vascular structures due to a granulomatous reaction, making complete removal extremely difficult. In such cases, it is always better to leave small bits of cyst lining rather than attempting total removal of the lesion with a high risk of damaging vital neurovascular structures. The incidence aseptic meningitis occurring can be diminished by taking care to avoid the spillage of cyst contents into the subarachnoid space, removal of the entire cyst lining and perioperative administration of steroids.
| Conclusion|| |
A male child presenting with precocious puberty should be investigated for an intracranial tumour. Although the most common tumour in precocious puberty is a hamartoma, an epidermoid should be considered in the differential diagnosis. They can have atypical CT and MRI appearances and hydrocephalus is occasionally seen. Epidermoid tumors should be treated by radical surgical resection. The risks of neural deficits because of manipulation or vascular injury and aseptic meningitis are greatly diminished if microsurgical techniques are utilized.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]
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