Tuberous Sclerosis Complex (TSC): Renal and Extrarenal Imaging

Tuberous sclerosis complex: Diagnostic features, surveillance, and therapeutic strategies

Tuberous sclerosis complex (TSC) is a rare neurocutaneous disorder of mTOR pathway dysregulation resulting from pathogenic variants in the TSC1 or TSC2 genes. Expression of this disorder may involve abnormal tissue growth and dysfunction within the brain, kidneys, heart, lungs, eyes, skin, bones, and teeth. Neurological manifestations can include subependymal giant cell astrocytomas (SEGAs), high rates of infantile spasms, drug-resistant epilepsy, developmental delay, cognitive impairment, autism spectrum disorder, and other neurobehavioral manifestations. Here we review the potential clinical manifestations of TSC by system, recommended diagnostic and surveillance testing, genetic testing, currently available therapeutic options, and considerations for education and social support resources given the unique challenges of this multi-system disorder.

New staging criteria predicting m-tor inhibitors treatment effect of renal angiomyolipoma in tuberous sclerosis complex patients

BACKGROUND

We aimed to launched new staging criteria to predict mTOR inhibitors treatment effect of renal angiomyolipomas (r-AMLs) in TSC patients.

METHODS

40 TSC patients with 69 r-AMLs were divided into two groups based on the efficacy of 6-month mTOR inhibitor treatment. Epidemiological data, therapeutic response, and predictive factors of enrolled patients were collected and analyzed. Age, sex, maximum diameter, maximum cross-sectional area (CSAmax), unenhanced mean CT value, enhanced mean CT value, and added value of enhanced CT of largest r-AML at baseline were assessed as potential influencing factors. Receiver operating characteristic (ROC) curve analysis and the area under the ROC curve (AUC) was used to estimate prediction power.

RESULTS

After 6 months of mTOR inhibitor treatment, the tumor reduction rates in the two groups were 55.87% and 16.44% (P < 0.001). At the start of treatment, the maximum diameters, CSAmax, added value of enhanced CT of the target lesion in two groups were 7.70 ± 0.73 cm vs. 13.18 ± 1.23 cm(P = 0.028), 57.40 ± 10.76cm2 vs. 167.29 ± 33.09cm2 (P = 0.015), and 62.32 ± 5.03HU vs. 33.06 ± 3.13HU (P = 0.009), respectively. AUCs of CSAmax, added value of enhanced CT, and combination of both were 0.8024, 0.7672, and 0.8116, respectively (P < 0.001). Cut-off values of CSAmax combined with the added value of enhanced CT were 40cm2 and 46HU. AUCs of maximum diameters, combination of maximum diameters and added value of enhanced CT were 0.7600 and 0.8100, respectively (P < 0.001), with cut-off values of 6.6 cm and 46 HU.

CONCLUSION

New staging criteria, based on CSAmax and added value of enhanced CT, can predict the treatment efficiency of m-TOR inhibitors for r-AMLs in TSC patients. A simplified version based on maximum diameter and added value of enhanced CT of lesion has also been proposed.

PMEL is a predictive biomarker for mTORC1 inhibitor treatment of renal angiomyolipoma in tuberous sclerosis complex patients

Background

We aimed to demonstrate the function of premelanosome protein (PMEL) as a biomarker to predict the effectiveness of mammalian target of rapamycin complex 1 (mTORC1) inhibitor treatment in renal angiomyolipomas (RAMLs) in tuberous sclerosis complex (TSC) patients.

Methods

95 whole blood samples from 49 patients diagnosed with TSC-RAMLs were collected. PMEL, N4BP2, and PCSK1N expression in the plasma samples were tested by quantitative sandwich ELISA. The target tumor volume assessed by maximum cross-sectional area (CSAmax) in CT scans. Correlation analysis was used to determine the relationship between PMEL expression and target tumors, as well as the tumor reduction rate.

Results

The tumor size of TSC-RAMLs positivity correlated with PMEL expression (r = 0.30, p = 0.036) and PCSK1N expression (r = 0.23, p = 0.027), but had no significant relationship with N4BP2 (r = 0.06, p = 0.89). The positive correlation between TSC-RAML tumor volume and PMEL expression still existed in TSC patients before (r = 0.30, p = 0.026) and after mTORC1 inhibitor treatment (r = 0.41, p = 0.0017), but the correlation between tumor volume and PCSK1N expression no longer existed. Further analysis found that PMEL expression negatively correlated with the reduction rate of TSC-RAMLs after mTORC1 inhibitor treatment (r = -0.50, p = 0.0022), both after 3 months (r = -0.47, p = 0.048) and 6 months of treatment (r = -0.52, p = 0.028).

Conclusion

PMEL expression positively correlated with the tumor size of TSC-RAMLs, and inversely with the reduction rate of TSC-RAMLs after mTORC1 inhibitor treatment, which may suggest that PMEL may serve as a predictive biomarker for the efficacy of mTORC1 inhibitor treatment.

Malignant tumors in tuberous sclerosis complex: a case report and review of the literature

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare, autosomal dominant genetic disease that arises from TSC1 or TSC2 genetic mutations. These genetic mutations can induce the development of benign tumors in any organ system with significant clinical implications in morbidity and mortality. In rare instances, patients with TSC can have malignant tumors, including renal cell carcinoma (RCC) and pancreatic neuroendocrine tumor (PNET). It is considered a hereditary renal cancer syndrome despite the low incidence of RCC in TSC patients. TSC is typically diagnosed in prenatal and pediatric patients and frequently associated with neurocognitive disorders and seizures, which are often experienced early in life. However, penetrance and expressivity of TSC mutations are highly variable. Herein, we present a case report, with associated literature, to highlight that there exist undiagnosed adult patients with less penetrant features, whose clinical presentation may contain non-classical signs and symptoms, who have pathogenic TSC mutations.

CASE PRESENTATION

A 31-year-old female with past medical history of leiomyomas status post myomectomy presented to the emergency department for a hemorrhagic adnexal cyst. Imaging incidentally identified a renal mass suspicious for RCC. Out of concern for hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome, the mass was surgically removed and confirmed as RCC. Discussion with medical genetics ascertained a family history of kidney cancer and nephrectomy procedures and a patient history of ungual fibromas on the toes. Genetic testing for hereditary kidney cancer revealed a 5'UTR deletion in the TSC1 gene, leading to a diagnosis of TSC. Following the diagnosis, dermatology found benign skin findings consistent with TSC. About six months after the incidental finding of RCC, a PNET in the pancreatic body/tail was incidentally found on chest CT imaging, which was removed and determined to be a well-differentiated PNET. Later, a brain MRI revealed two small cortical tubers, one in each frontal lobe, that were asymptomatic; the patient's history and family history did not contain seizures or learning delays. The patient presently shows no evidence of recurrence or metastatic disease, and no additional malignant tumors have been identified.

CONCLUSIONS

To our knowledge, this is the first report in the literature of a TSC patient without a history of neurocognitive disorders with RCC and PNET, both independently rare occurrences in TSC. The patient had a strong family history of renal disease, including RCC, and had several other clinical manifestations of TSC, including skin and brain findings. The incidental finding and surgical removal of RCC prompted the genetic evaluation and diagnosis of TSC, leading to a comparably late diagnosis for this patient. Reporting the broad spectrum of disease for TSC, including more malignant phenotypes such as the one seen in our patient, can help healthcare providers better identify patients who need genetic evaluation and additional medical care.

Tuberous sclerosis complex combined with primary lymphedema: A case report

BACKGROUND

Tuberous sclerosis complex (TSC) and primary lymphedema (PLE) are both rare diseases, and it is even rarer for both to occur in the same patient. In this work, we have provided a detailed description of a patient's clinical presentation, imaging findings, and treatment. And a retrospective analysis was conducted on 14 published relevant case reports.

CASE SUMMARY

A 16-year-old male came to our hospital for treatment due to right lower limb swelling. This swelling is already present from birth. The patient's memory had been progressively declining. Seizures had occurred 1 year prior at an unknown frequency. The patient was diagnosed with TSC combined with PLE through multimodal imaging examination: Computed tomography, magnetic resonance imaging, and lymphoscintigraphy. The patient underwent liposuction. The swelling of the patient's right lower limb significantly improved after surgery. Epilepsy did not occur.after taking antiepileptic drugs and sirolimus.

CONCLUSION

TSC with PLE is a rare and systemic disease. Imaging can detect lesions of this disease, which are important for diagnosis and treatment.

Tumorigenesis Mechanisms Found in Hereditary Renal Cell Carcinoma: A Review

Renal cell carcinoma is a heterogenous cancer composed of an increasing number of unique subtypes each with their own cellular and tumor behavior. The study of hereditary renal cell carcinoma, which composes just 5% of all types of tumor cases, has allowed for the elucidation of subtype-specific tumorigenesis mechanisms that can also be applied to their sporadic counterparts. This review will focus on the major forms of hereditary renal cell carcinoma and the genetic alterations contributing to their tumorigenesis, including von Hippel Lindau syndrome, Hereditary Papillary Renal Cell Carcinoma, Succinate Dehydrogenase-Deficient Renal Cell Carcinoma, Hereditary Leiomyomatosis and Renal Cell Carcinoma, BRCA Associated Protein 1 Tumor Predisposition Syndrome, Tuberous Sclerosis, Birt-Hogg-Dubé Syndrome and Translocation RCC. The mechanisms for tumorigenesis described in this review are beginning to be exploited via the utilization of novel targets to treat renal cell carcinoma in a subtype-specific fashion.

Benign tumors in TSC are amenable to treatment by GD3 CAR T cells in mice

Mutations underlying disease in tuberous sclerosis complex (TSC) give rise to tumors with biallelic mutations in TSC1 or TSC2 and hyperactive mammalian target of rapamycin complex 1 (mTORC1). Benign tumors might exhibit de novo expression of immunogens, targetable by immunotherapy. As tumors may rely on ganglioside D3 (GD3) expression for mTORC1 activation and growth, we compared GD3 expression in tissues from patients with TSC and controls. GD3 was overexpressed in affected tissues from patients with TSC and also in aging Tsc2+/- mice. As GD3 overexpression was not accompanied by marked natural immune responses to the target molecule, we performed preclinical studies with GD3 chimeric antigen receptor (CAR) T cells. Polyfunctional CAR T cells were cytotoxic toward GD3-overexpressing targets. In mice challenged with Tsc2-/- tumor cells, CAR T cells substantially and durably reduced the tumor burden, correlating with increased T cell infiltration. We also treated aged Tsc2+/- heterozygous (>60 weeks) mice that carry spontaneous Tsc2-/- tumors with GD3 CAR or untransduced T cells and evaluated them at endpoint. Following CAR T cell treatment, the majority of mice were tumor free while all control animals carried tumors. The outcomes demonstrate a strong treatment effect and suggest that targeting GD3 can be successful in TSC.