Everolimus for Retinal Astrocytic Hamartomas in Tuberous Sclerosis Complex

Ocular and orbital tumors in childhood

Pediatric tumors of the eye and orbit can be benign or malignant as well as congenital or acquired and are usually distinctively different than those seen in adults. Although most of these neoplasms are benign (eg, dermoid cyst, chalazion, molluscum), their location near and within a vital organ can result in serious dermatologic and ophthalmologic sequelae. Lesions discussed include vascular lesions, retinoblastomas (the most common primary pediatric intraocular malignancy), rhabdomyosarcoma (the most common primary pediatric orbital malignancy), Langerhans cell histiocytosis, and metastatic lesions to the orbit (neuroblastoma, Ewing sarcoma). Although cysts and ocular melanoma can occur within the pediatric population, these conditions are covered in other contributions in this issue of Clinics in Dermatology.

Long-term efficacy and safety of sirolimus for retinal astrocytic hamartoma associated with tuberous sclerosis complex

Mammalian target of rapamycin (mTOR) inhibitors (sirolimus or everolimus) have been demonstrated effective in reducing the size of tuberous sclerosis complex (TSC)-associated retinal astrocytic hamartoma (RAH) in short term. To investigate the long-term efficacy and safety of sirolimus on TSC-associated RAH, 13 TSC-associated RAH patients (59 RAH lesions) who received sirolimus therapy for at least 2 years were retrospectively enrolled in this study. Changes in the maximal thickness (MT) of RAH on optical coherence tomography and the longest base diameter (LBD) of RAH on color fundus photography were assessed. The results showed that for a mean follow-up of 39 months, sirolimus was associated with a mean reduction of 14.6% in MT and 6.8% in LBD of RAHs. The main impacts of sirolimus occurred within the first 6–12 months, with 14.8% reduction in MT and 4.7% reduction in LBD. Mouth ulceration (10 [76.9%]) and acne (9 [69.2%]) were the most common adverse events. These follow-up data support the long-term use of sirolimus in TSC-associated RAH patients, and persistent use of sirolimus possibly prevents tumor regrowth.

Treatment of Aggressive Retinal Astrocytic Hamartoma with Oral mTOR Inhibition

OBJECTIVE OR PURPOSE

To describe the clinical course and outcomes of aggressive retinal astrocytic hamartoma (RAH) treated with oral mTOR inhibitors (mTORi).

DESIGN

Retrospective clinical case series.

SUBJECTS, PARTICIPANTS, AND/OR CONTROLS

Five patients with genetically confirmed TSC and visually significant RAH due to tumor growth or exudation.

METHODS, INTERVENTION, OR TESTING

Review of the electronic medical record in this retrospective clinical case series was performed to determine baseline and follow-up ophthalmologic examination characteristics along with ancillary imaging findings, in patients receiving off-label treatment with either oral sirolimus or everolimus for symptomatic RAH.

MAIN OUTCOME MEASURES

Visual acuity, change in tumor size, degree of exudation, and adverse effects of mTORi were evaluated.

RESULTS

The five patients in this series ranged in age from 8 months to 54 years. Four were treated with sirolimus, and one received everolimus. In all cases, tumor height was stable or decreased following treatment (median follow-up: 39 months, range 11-73 months). Exudation improved following treatment in all cases. In the 8-month-old infant, frequent upper respiratory tract infections prompted cessation of treatment. In one patient, the mTORi was temporarily held due to elevated liver enzymes. No other significant adverse effects were noted.

CONCLUSIONS

Sirolimus and everolimus should be considered in the management of vision-threatening RAH, particularly in the setting of exudative and rapidly growing tumors. Four out of five patients in this series tolerated oral mTORi and continued on therapy. There were no serious complications.

TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.

[Tumors and Pseudotumors of the Retina and the Ciliary Epithelium]

The variety of retinal tumors ranges from harmless lesions to benign, locally destructive tumors and life-threatening diseases, and they are not always easy to distinguish from each other. The differential diagnosis includes real neoplasia, reactive inflammatory pathologies and vascular anomalies of the fundus as well. If possible, the diagnosis should be made clinically in order to avoid the danger of tumor cell spread via invasive diagnostic tools. Nevertheless, genetic analysis of the pathology is gaining more importance and adds to the precise characterization of the diagnosis. Depending on the tumor entity, therapy in a specialized center is necessary.

Tumoren und Pseudotumoren der Netzhaut und des Ziliarepithels

Die Varietät retinaler Tumoren reicht von harmlosen Läsionen über benigne, lokal destruierende Tumoren bis hin zu lebensbedrohlichen Erkrankungen. Nicht immer lassen sie sich einfach voneinander unterscheiden. Die Diagnose sollte nach Möglichkeit klinisch gestellt werden wegen der Gefahr einer Tumorzellverschleppung durch invasive Diagnostik. Jedoch rückt die genetische Charakterisierung der Läsion immer mehr in den Vordergrund. Je nach Entität ist eine Therapie in einem spezialisierten Zentrum notwendig.