Hypothalamic hamartomas and sexual precocity

Surgical and radiosurgical treatment of hypothalamic hamartoma: The Italian experience between 2011 and 2021

OBJECTIVE

To investigate the Italian experience on the surgical and radiosurgical treatment of drug-resistant epilepsy due to hypothalamic hamartoma (HH) in the period 2011-2021 in six Italian epilepsy surgery centers, and to compare safety and efficacy profiles of the different techniques.

METHODS

We collected pseudo-anonymized patient's data with at least 12 months of follow-up. Surgical outcome was defined according to Engel classification of seizure outcome. Univariate analysis was performed to assess the risk of post-operative seizures, categorized in dichotomous variable as favorable and unfavorable; explanatory variables were considered. Mann-Whitney or Chi-squared test were used to assess the presence of an association between variables (p < 0.05).

RESULTS

Full presurgical and postoperative data about 42 patients from 6 epilepsy surgery centers were gathered. Engel class I was reached in the 65.8% and 66.6% of patients with gelastic and non-gelastic seizures, respectively. Other than daily non-gelastic seizures were associated with seizure freedom (p = 0.01), and the radiological type presented a trend toward significance (p = 0.12).

SIGNIFICANCE

Endoscopic disconnection and laser interstitial thermal therapy are effective in the treatment of HH-related epilepsy, with a tolerable safety profile. Both gelastic and non-gelastic seizures can be treated, also in patients with a long history of seizures.

PLAIN LANGUAGE SUMMARY

This study collected data about 42 patients with HH-related epilepsies. Endoscopic disconnection and laser therapy are both effective and safe in the treatment of hypothalamic hamartoma-related epilepsies.

Hypothalamic hamartoma with epilepsy: Review of endocrine comorbidity

The most common, and usually the only, endocrine disturbance in patients with hypothalamic hamartoma (HH) and epilepsy is central precocious puberty (CPP). The mechanism for CPP associated with HH may relate to ectopic generation and pulsatile release of gonadotropin-releasing hormone (GnRH) from the HH, but this remains an unproven hypothesis. Possible regulators of GnRH release that are intrinsic to HH tissue include the following: (1) glial factors (such as transforming growth factor α[TGFα) and (2) γ-aminobutyric acid (GABA)-mediated excitation. Both are known to be present in surgically-resected HH tissue, but are present in patients with and without a history of CPP, suggesting the possibility that symptoms related to HH are directly associated with the region of anatomic attachment of the HH to the hypothalamus, which determines functional network connections, rather than to differences in HH tissue expression or pathophysiology. CPP associated with HH presents with isosexual development prior to the age of 8 years in girls and 9 years in boys. It is not uncommon for CPP with HH to present in children at an earlier age in comparison to other causes of CPP, including in infancy. Surgical resection of the HH can be effective for treating CPP, but is reserved for patients with intractable epilepsy, since GnRH agonists are widely available and effective treatment. Other endocrine disturbances with HH are rare, but can include growth hormone deficiency, hypothyroidism, and adrenal insufficiency. Diabetes insipidus is commonly encountered postoperatively, but is not observed with HH prior to surgical intervention.

Autoimmune thyroiditis and diabetes mellitus type 1 after long-term gonadotropin-releasing hormone agonist treatment for central precocious puberty: evolution or coincidence?

Very few abnormalities in endocrine function have been reported during long term gonadotropin-releasing hormone agonist (GnRHa) treatment in girls. Most authors agree that this therapy is safe and effective. We present an unusual outcome of long term GnRHa therapy in two girls with central precocious puberty(CPP) of idiopathic or organic origin. They have received monthly depot injections of triptorelin acetate for a time period of 8 years. Thyroid function was examined by measuring serum levels of thyrotropin (TSH), thyroxine (T4), thyroid antibodies, and ultrasound of the thyroid gland. One of the girls was at the age of 8.5 years, having elevated thyroid antibodies, mild goitier and an abnormal ultrasound of the thyroid gland, suggesting autoimmune thyroiditis. Another girl with a hypothalamic hamartoma developed diabetes mellitus at the age of 9 years. Both of these girls were early diagnosed for CPP, at 6 months and 8 months respectively, and given GnRHa treatment. So far, it is not known whether these autoimmune diseases are related to the GnRHa treatment or are simply a coincidence. However, we suggest a closer monitoring of girls with CPP who have had a long period of treatment.

Exclusion of candidate loci and cholesterol biosynthetic abnormalities in familial Pallister-Hall syndrome

Pallister-Hall syndrome (PHS) was originally described in 1980 in six sporadic cases of children with structural anomalies including hypothalamic hamartoma, polydactyly, imperforate anus, and renal and pulmonary anomalies. In 1993, the first familial cases were reported, including affected sibs and vertical transmission. Three of these families are sufficiently large to allow initial evaluation by linkage studies to candidate genes or loci. We have evaluated candidate loci for PHS based on three clinical observations. The first is a patient with PHS-like malformations, including a hypothalamic hamartoma, and an unbalanced translocation involving 7q and 3p. The second is a family with familial PHS where the founder's father had an autosomal dominant hand malformation previously mapped to 17q. The third is the phenotypic overlap of PHS and Smith-Lemli-Opitz syndrome. In this report, we exclude these loci as candidates for linkage to the PHS phenotype on the basis of lod scores of less than-2.0. We conclude that hypothalamic hamartoma is not specific to PHS and that the dominant hand malformation in one of the families was a coincidence. To evaluate the relationship of PHS to Smith-Lemli-Opitz syndrome, we analysed levels of cholesterol and intermediate metabolites of the later stages of cholesterol biosynthesis. There is no evidence of a generalised disorder of cholesterol biosynthesis in patients with familial PHS. On genetic and biochemical grounds, we conclude that PHS and Smith-Lemli-Opitz syndrome are not allelic variants of a single locus.

Central neuronal tumors in childhood: relationship to dysplasia

A survey of 1,500 brain tumors at The Hospital for Sick Children in Toronto reveals that about 20-25% of tumors demonstrate some form of neuronal differentiation. At one end of the spectrum are the well-defined ganglionic tumors, sometimes difficult to differentiate from cortical dysplasia. At the other extreme are primitive neuroectodermal tumors with neuronal differentiation often confined to immunohistochemical observations. Of the total number of tumors, approximately 5% have a definitive ganglionic component, the majority being ganglioglioma, and others include dysembryoplastic neuroepithelial tumor, infantile ganglioglioma, paraganglioma, central neurocytoma, and gangliocytoma. Some tumors such as subependymal giant cell tumor associated with tuberous sclerosis occasionally have evidence of neuronal differentiation with immunoreactivity with antisera to neuron-specific enolase and negativity with antisera to GFAP. In children with epilepsy, improved brain imaging has identified lesions which on examination following temporal lobectomy show varying degrees of cortical dysplasia. At this site, there is also a high incidence of gangliogliomas. Is there a relationship between cortical dysplasia and neuronal tumors? Following a primary induction event during development, embryonal dysplasia and/or neoplasia may occur. The lesion may be malformative as in unilateral megalencephaly, hamartomatous as in tuberous sclerosis, neoplastic as in congenital tumors, or a combination of malformative and neoplastic.(ABSTRACT TRUNCATED AT 250 WORDS)