Hypothalamic hamartoma: a report of 2 cases

Is surgery effective for treating hypothalamic hamartoma causing isolated central precocious puberty? A systematic review

The aim of this review was to determine the role of surgery in treating hypothalamic hamartoma (HH) causing isolated central precocious puberty (CPP). Literature review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patients with isolated CPP due to HH, managed with surgical resection, were included. We found 33 studies, reporting 103 patients (76 pedunculated, 27 sessile). Patients were considered "cured" if the symptoms of PP had regressed and the hormone profile had normalized after surgery. Indications for surgery included hamartoma deemed surgically resectable (n-12), for the purpose of tissue diagnosis (n-3), partial response/failure of preoperative therapy (n-9), and unable to afford/to avoid long-term medical therapy (n-7). The extent of resection was total (TR) (n-39), near total/subtotal (NTR/STR) (n-20), partial (PR) (n-35), or unspecified (n-9). On follow-up (range: 3 months-16 years), 73.6% (56/76) of patients with pedunculated HH were cured, while 17.1% (13/76) had partial relief. Only 3/27 (11.1%) of patients with sessile HH were cured. All patients with a pedunculated hamartoma who underwent TR (n=36) improved, with 88.88% cured of the symptoms. Surgery had no effect in 17/23 (73.9%) patients with sessile HH who underwent PR. Psychological symptoms improved in 10/11 patients. There was no mortality. Permanent complications, in the form of 3rd nerve palsy, occurred in 3.7% (2/54) of the patients. To conclude, in the current era of availability of GnRH analogs, surgical resection in a subset of patients may be acceptable especially for small pedunculated hamartomas.

Tuber Cinereum Hamartomas and Gelastic Epilepsy

We studied five patients with gelastic epilepsy sustained by hamartoma of the tuber cinereum, submitted to EEG and Video-EEG study and to MR examination. The mechanism of ictal laughter, clinical associations and prognosis for seizure control are discussed.

Hamartomas should be always suspected when gelastic seizures occur, and appropriate diagnostic tools should be employed for their diagnosis. In patients presenting with gelastic epilepsy, MR assessment of the hypothalamic region is necessary to identify a hamartoma of the tuber cinereum.

Moreover, the resolution of MR imaging provides a basis to correlate some of the clinical manifestations with the anatomical disposition of the lesion within the hypothalamus.

Gelastic epilepsy seems to correlate with large broad-based hamartomas in relationship with the mamillary bodies. In these cases, surgical treatment should be considered when symptoms are not sufficiently responsive to medical therapy.

Central precocious puberty due to hypothalamic hamartomas correlates with anatomic features but not with expression of GnRH, TGFalpha, or KISS1

BACKGROUND/AIMS

Hypothalamic hamartomas are the most common identifiable cause of central precocious puberty (CPP). Hamartoma characteristics proposed to be associated with CPP include specific anatomic features and expression of molecules such as gonadotropin-releasing hormone (GnRH), transforming growth factor alpha (TGFalpha), and GRM1A, which encodes the type 1 metabotropic glutamate receptor alpha isoform. We sought to determine whether hamartomas that cause CPP could be distinguished by anatomic features, expression of these molecules, or expression of KISS1, whose products signal through the receptor GPR54 to stimulate GnRH release.

METHODS

Clinical records and radiologic images were reviewed for 18 patients who underwent hamartoma resection for intractable seizures; 7 had precocious puberty. Resected tissue was examined for expression of GnRH, GnRH receptor (GnRHR), TGFalpha, KISS1, GPR54, and GRM1A.

RESULTS

Hypothalamic hamartomas associated with CPP were more likely to contact the infundibulum or tuber cinereum and were larger than hamartomas not associated with CPP. GnRH, TGFalpha, and GnRHR were expressed by all hamartomas studied. Expression of KISS1, GPR54, and GRM1A did not differ significantly between hamartomas associated and not associated with CPP.

CONCLUSION

Anatomic features rather than expression patterns of candidate molecules distinguish hypothalamic hamartomas that are associated with CPP from those that are not.

Hypothalamic Hamartoma

The incidence of hypothalamic hamartomas (HHs) has increased since the introduction of magnetic resonance (MR) imaging. The etiology of this anomaly and the pathogenesis of its peculiar symptoms remain unclear, but recent electrophysiological, neuroimaging, and clinical studies have yielded important data. Categorizing HHs by the degree of hypothalamic involvement has contributed to the accurate prediction of their prognosis and to improved treatment strategies. Rather than undergoing corticectomy, HH patients with medically intractable seizures are now treated with surgery that targets the HH per se, e.g. HH removal, disconnection from the hypothalamus, stereotactic irradiation, and radiofrequency lesioning. Although surgical intervention carries risks, total eradication or disconnection of the lesion leads to cessation or reduction of seizures and improves the cognitive and behavioral status of these patients. Precocious puberty in HH patients is safely controlled by long-acting gonadotropin-releasing hormone agonists. The accumulation of knowledge regarding the pathogenesis of symptoms and the development of safe, effective treatment modalities may lead to earlier intervention in young HH patients and prevent the decline in their cognitive abilities and quality of life. This review of hypothalamic hamartomas presents current classifications, pathophysiologies, and treatment modalities.

Hypothalamic hamartoma with precocious puberty

Hypothalamic hamartoma is a rare congenital nonneoplastic heterotopia consisting of neurons, glial cells and fiber bundles. Clinically, most patients with hypothalamic hamartomas present with precocious puberty and/or gelastic epilepsy. We report an interesting case of hypothalamic hamartoma causing precocious puberty in a young male. The lesion was excised totally through frontotemporal craniotomy and transSylvian approach without any added morbidity.

Gonadotrophin and prolactin secretory dynamics in girls with normal puberty, idiopathic precocious puberty and precocious puberty due to hypothalamic hamartoma

OBJECTIVE

This study was designed to test the hypothesis that hypothalamic hamartoma causes precocious puberty through a different neuroendocrine mechanism than that of normal puberty or of idiopathic precocious puberty.

DESIGN AND PATIENTS

We compared the pattern of gonadotrophin secretion among 4 girls with precocious puberty due to hypothalamic hamartoma, 27 girls with idiopathic precocious puberty, and 14 girls with normal puberty. All subjects were breast stage 3 or 4. Blood samples were obtained every 20 min for 4 h during the day (1.000 hours to 1400 h) and night (22.00 hours to 0200 h).

MEASUREMENTS

LH, FSH, and prolactin were measured in each blood sample. Girls also underwent LHRH-stimulation with measurement of LH and FSH before and after stimulation.

RESULTS

There were no significant differences in mean LH level, LH peak amplitude, or LH or FSH peak frequency during either the day or the night among the three diagnostic groups. However, the mean +/- SD LHRH-stimulated peak LH levels were greater in girls with hypothalamic hamartoma than in girls with normal puberty or with idiopathic precocious puberty (194 +/- 142 vs 85 +/- 60 or 66 +/- 54 IU/l, respectively, P < 0.05). The LHRH-stimulated peak FSH level in girls with hypothalamic hamartoma exceeded the level for the normal pubertal girls (31 +/- 19 vs 17 +/- 7 IU/l, P < 0.05), but not the level for the girls with idiopathic precocious puberty (25 + 12 IU/l). The peak LH to peak FSH ratio in the girls with hypothalamic hamartoma exceeded the ratio for the girls with idiopathic precocious puberty (7.3 +/- 3.9 vs 2.6 +/- 3.0 IU/l, P < 0.05), but not the ratio for the normal pubertal girls (5.0 + 2.9). There were no significant differences in mean prolactin level, peak amplitude or frequency, or in the ratio of mean night to mean day prolactin, among the 3 diagnostic groups.

CONCLUSIONS

We conclude that spontaneous gonadotrophin and prolactin secretion are similar among girls with hypothalamic hamartoma, idiopathic precocious puberty, or normal puberty. However, the increased LHRH-stimulated peak LH in the girls with hypothalamic hamartoma suggests subtle differences in neuroendocrine regulation that may underlie their more rapid pubertal maturation.

Idiopathic isosexual central precocious puberty: magnetic resonance findings in 30 patients

The purpose of this prospective study was to define the incidence of magnetic resonance imaging (MRI) abnormalities in the brain in patients with idiopathic central precocious puberty without any additional neurological signs and symptoms, and to evaluate the routine use of gadolinium contrast in these patients. 30 patients (29 girls, one boy; age range 1.9-11.9 years) with idiopathic central precocious puberty were studied. MRI of the brain in axial, coronal and sagittal planes was performed before and after administration of gadopentetate dimeglumine, with special attention to the region of the third ventricle. There are three major findings: (1) the height of the pituitary gland is increased up to adult size compared with normal individuals; (2) in four patients (13%) major structural abnormalities were found; three hamartomas of the tuber cinereum and one gliomatous process extending from the chiasm to the optic tract; and (3) the routine use of gadopentetate dimeglumine did not reveal new abnormalities although the lack of enhancement made a positive contribution to diagnostic certainty. We conclude that contrast enhanced MR examination is a safe and reliable method for the exclusion of abnormalities in children with precocious puberty and for the follow-up of those patients in whom abnormalities are present.

Neurosurgical treatment of hypothalamic hamartomas causing precocious puberty

Five children, three girls and two boys, were treated for precocious puberty secondary to hypothalamic hamartoma by resection of the hamartoma. The patients' ages at onset of pubertal development ranged from 6 to 19 months. The hamartomas ranged in size from 6 to 10 mm; four were pedunculated, one was sessile, and all were located below the tuber cinereum. The hamartomas were excised via a right subtemporal approach, with transection at the inferior surface of the hypothalamus; two were adherent posteriorly to the basilar artery and brain stem, and the adhesions were divided. Postoperatively, three children exhibited a transient oculomotor paresis and one other child required eye-muscle surgery. The symptoms and signs of precocious puberty completely regressed postoperatively in all patients. Preoperative hormone assays of testosterone, luteinizing hormone, and follicle-stimulating hormone were within the pubertal range in all five children; postoperative assays fell to prepubertal levels. The children have been followed for 0.5 to 10.5 years (mean 5.0 years) postoperatively, without evidence of recurrence of precocious puberty. One child has begun spontaneous puberty at a normal age. It is concluded that complete resection of hypothalamic hamartomas causing precocious puberty is curative.

Intrasellar gangliocytoma with multiple immunoreactivities

The authors report a rare case of intrasellar gangliocytoma without endocrinopathy. The tumor, removed by transsphenoidal surgery, exhibited immunoreactivities for VIP and galanin in the cytoplasm of several nerve cells, a-subunit, somatostatin, and serotonin in the cytoplasm of few nerve cells. Our case indicates that gangliocytomas can produce unusual combinations of peptides which, despite their known biologic activity, do not invariably cause clinical abnormalities.

Mixed gangliocytoma-adenoma: a distinct neuroendocrine tumor of the pituitary fossa

A mixed gangliocytoma-adenoma occurring in the pituitary fossa of a patient who presented with acromegaly, galactorrhea, and headaches is described. Immunohistochemical studies demonstrated the gangliocytic portion of the tumor to be composed nearly entirely of ganglion cells enmeshed in their neuritic processes and disclosed focal presence of growth hormone and prolactin-secreting cells in the adenoma. Ultrastructurally, some of the larger ganglion cells contained (and were often filled with) zebra-like bodies, while the adenoma was shown to be sparsely granulated with numerous fibrous bodies. These findings support the term of mixed gangliocytoma-adenoma for these rare intrasellar tumors and provide additional support for their nature as independent neuroendocrine units.