Long-term treatment of cancer-prone germline PTEN mutant mice with low-dose rapamycin extends lifespan and delays tumour development.

PTEN is one of the most commonly inactivated tumour suppressor genes in sporadic cancer. Germline heterozygous PTEN gene alterations also underlie PTEN hamartoma tumour syndrome (PHTS), a rare human cancer-predisposition condition. A key feature of systemic PTEN deregulation is the inability to adequately dampen PI3-kinase (PI3K)/mTORC1 signalling. PI3K/mTORC1 pathway inhibitors such as rapamycin are therefore expected to neutralise the impact of PTEN loss, rendering this a more druggable context compared with those of other tumour suppressor pathways such as loss of TP53. However, this has not been explored in cancer prevention in a model of germline cancer predisposition, such as PHTS. Clinical trials of short-term treatment with rapamycin have recently been initiated for PHTS, focusing on cognition and colon polyposis. Here, we administered a low dose of rapamycin from the age of 6 weeks onwards to mice with heterozygous germline Pten loss, a mouse model that recapitulates most characteristics of human PHTS. Rapamycin was well tolerated and led to a highly significant improvement of survival in both male and female mice. This was accompanied by a delay in, but not full blockade of, the development of a range of proliferative lesions, including gastro-intestinal and thyroid tumours and endometrial hyperplasia, with no impact on mammary and prostate tumours, and no effect on brain overgrowth. Our data indicate that rapamycin may have cancer prevention potential in human PHTS. This might also be the case for sporadic cancers in which genetic PI3K pathway activation is an early event in tumour development, such as endometrial cancer and some breast cancers. To the best of our knowledge, this is the first report of a long-term treatment of a germline cancer predisposition model with a PI3K/mTOR pathway inhibitor. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Sirolimus treatment of a PTEN hamartoma tumor syndrome presenting with melena.

BACKGROUND: PTEN hamartoma tumor syndrome (PHTS) is an umbrella term including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), PTEN-related Proteus syndrome (PS), and PTEN-related Proteus-like syndrome. One of the disorders in PHTS spectrum, CS is characterized by macrocephaly, mucocutaneous findings, gastrointestinal system (GIS) polyposis and an increased lifetime risk of GIS, breast, thyroid and other cancers. CASE: In this study, we report an adolescent patient presenting with recurrent life-threatening upper GIS bleeding as a result of hamartomatous polyposis. Genetic studies revealed a known pathogenic nonsense mutation confirming the initial diagnosis of CS. CONCLUSIONS: Additionally, we describe our therapeutic intervention to improve the patient`s clinical symptoms with sirolimus, which its use is infrequently addressed in the literature for pediatric age group harboring PTEN mutations.

Eight years of experience with vismodegib for advanced and multiple basal cell carcinoma patients in the Netherlands: a retrospective cohort study.

BACKGROUND: Vismodegib has been used for the treatment of locally advanced basal cell carcinoma (laBCC) and metastatic BCC (mBCC) since 2011. Most efficacy and safety data are provided by clinical trials. This study evaluates the effectiveness of vismodegib for the treatment of laBCC, mBCC and basal cell nevus syndrome (BCNS) patients, and the tumour characteristics associated with a higher probability of achieving a complete response in the Netherlands. METHODS: A retrospective cohort study that included all patients ≥18 years with histologically proven basal cell carcinoma that received ≥1 dose of vismodegib between July 2011 and September 2019 in the Netherlands. RESULTS: In total, 48 laBCC, 11 mBCC and 19 BCNS patients were included. Median progression-free survival was 10.3 months (95% confidence interval (CI), 7.5-22.6) for laBCC, 11.7 (95% CI, 5.2-17.5) for mBCC and 19.1 (95% CI, 7.4-20.2) for BCNS. Larger laBCCs were associated with a lower probability of complete response (hazard ratio (HR) 0.77 per increase in cm, p = 0.02). Of all BCNS patients, 63% received ≥2 treatment sequences with vismodegib; all achieved partial responses. CONCLUSIONS: Half of the aBCC patients progress within 1 year after the start of vismodegib treatment. More research is needed to investigate other treatment strategies after vismodegib progression and to evaluate long-term effects of repetitive vismodegib treatment.

Clues to primary vismodegib resistance lie in histology and genetics.

Basal cell carcinoma (BCC) is the most common human malignant neoplasm. However, there are multiple BCC subtypes that share clinical features while demanding different management. We present a case of a woman with hundreds of BCCs throughout her body that were resistant to vismodegib and without other features of basal cell nevus syndrome. Histological results of biopsies taken from various sites revealed three lesions characteristic of infundibulocystic BCCs (IBCCs) and two BCCs. Paired whole-exome sequencing performed using DNA isolated from blood and one of her IBCCs uncovered a germline heterozygous SUFU (Suppressor of Fused) mutation. The downstream location of SUFU in the hedgehog pathway explains why its mutation results in IBCCs that will not respond to any therapeutics that target upstream components of SUFU These results capture the significance of histological and genetic analysis in directing treatment.

Long-term therapy of multiple basal cell carcinomas: Clinicodermoscopic score for monitoring of intermittent vismodegib treatment.

Vismodegib treatment of multiple basal cell carcinomas (BCCs) is limited by adverse effects and high relapse rates: intermittent regimens are therefore preferred for long-term administration. The objective of this study was to investigate clinical and dermoscopic changes in BCCs during long-term intermittent treatment and to identify those most indicative of tumor persistence/clearing. Clinical and dermoscopic images (n = 380 each) of 38 BCCs were acquired at 10 observation times (t0-t9). Biopsies were performed at baseline (t0) and after 72 weeks of treatment (t9). All images were evaluated retrospectively by experts who assessed the presence/absence of 12 clinical and 14 dermoscopic features: clinical scores (CScs) and dermoscopic scores (DScs) were then calculated.

A Pilot Study of Sirolimus in Subjects with Cowden Syndrome or Other Syndromes Characterized by Germline Mutations in PTEN.

LESSONS LEARNED: This is the first human interventional study in patients with Cowden syndrome that is driven by inactivation of germline PTEN gene.Single-agent sirolimus, a mTOR inhibitor, suppressed mTOR signaling in surrogate human tissues without significant toxicity. BACKGROUND: Cowden syndrome is characterized by inactivating germline PTEN mutations, which can lead to activation of the PI3K-Akt-mTOR pathway. METHODS: Adult subjects with germline PTEN mutation who met international diagnostic criteria for Cowden syndrome and who had Eastern Cooperative Oncology Group (ECOG) performance status 0-2 and adequate organ function were enrolled. Subjects were treated with a 56-day course of daily oral sirolimus. In addition to symptom assessment and physical examination, dermatologic, endoscopic, neurologic (cerebellar), and radiographic assessments were conducted. Inhibition of the mTOR pathway in benign skin and gastrointestinal (GI) lesion was assessed by immunohistochemistry. RESULTS: A total of 18 patients and 16 families were enrolled. PTEN mutations were located at exons 1-8. Regression of skin and GI lesions was observed by dermoscopy or endoscopy. Neurological evaluation showed improvement in cerebellar function score at 1 month. Immunohistochemistry (IHC) analysis in skin and GI benign lesions showed a decrease in the ratio of phosphorylated (p)S6 to total S6 in response to sirolimus. Ratios of pS6K to total S6 at days 14 and 56 were significantly lower than at baseline (p = .0026, p = .00391, respectively). A 56-day course of sirolimus was well tolerated. CONCLUSION: A 56-day course of sirolimus was well tolerated in subjects with Cowden syndrome and was associated with some evidence of improvement in symptoms, skin and GI lesions, cerebellar function, and decreased mTOR signaling.

Bilateral Recurrent Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos Disease) in Cowden Syndrome: A Case Report and Literature Review.

BACKGROUND: Dysplastic gangliocytoma (Lhermitte-Duclos disease [LDD]) typically presents as a PTEN (phosphatase and tensin homolog)-positive, insidious unilateral mass of the cerebellar cortex. Patients can present with symptoms of increased intracranial pressure. Magnetic resonance imaging (MRI) will reveal a characteristic laminar/tigroid appearance. Surgical management has been superior to conservative measures for symptomatic lesions. The outcomes for bilateral craniotomy have not yet been described. CASE DESCRIPTION: A 50-year-old patient with Cowden syndrome had initially presented with vertigo and imbalance. T2-weighted MRI showed a striated pattern of hypointensity and hyperintensity in bilateral cerebellar hemispheres consistent with Lhermitte-Duclos disease. He underwent right posterior fossa craniotomy with near total surgical resection and achieved symptom resolution. However, 3 years later, asymptomatic recurrence of the right-sided LDD and progression of left-sided LDD were noted. These were managed with a 1-year course of temozolomide. Both lesions remained stable until 4 years after completion of temozolomide. MRI demonstrated progression in the left hemisphere requiring a second surgical resection. PTEN analysis of the resected lesion was negative for mutation. CONCLUSIONS: To the best of our knowledge, the present case is the first reported case of bilateral cerebellar hemisphere LDD ultimately managed by temporally dissociated bilateral surgical resections. Our patient was unique in that he had undergone surgery for resection of LDD, followed by a second surgery for contralateral progression 8 years later. The therapeutic options to prevent recurrence are limited, although temozolomide did seem to impede progression. Symptomatic patients will typically benefit most from surgical intervention. Given the strong association between adult LDD and Cowden syndrome, maintaining close follow-up care and possible surveillance imaging will be essential.

Use of vismodegib for the treatment of multiple basal cell carcinomas in a patient with xeroderma pigmentosum.

A female patient with xeroderma pigmentosum and multiple basal cell carcinomas was treated with a hedgehog pathway inhibitor (vismodegib), which successfully treated the majority of her basal cell carcinomas while preventing the appearance of new lesions. The sum diameter of lesions showed a 61% decrease after 16.5 months of treatment, although after 18.5 months of treatment, a persistent lesion showed progression and metatypical characteristics; adverse events included persistent alopecia muscle cramps, dysgeusia, and amenorrhea. Despite these limitations, vismodegib may have a role in the treatment of some patients with xeroderma pigmentosum.

Childhood Lhermitte-Duclos Disease Progressing to Medulloblastoma in Bilateral Cerebellar Hemispheres: Report of Unusual Case.

BACKGROUND: Lhermitte-Duclos disease is an extremely rare pathologic entity characterized by a cerebellar mass composed of enlarged cerebellar folia containing abnormal ganglion cells. This entity usually presents in young and middle-aged adults and rarely in children. There is no study in the literature analyzing the long-term clinical course of this disease to assess the behavior primarily because of its rarity. CASE DESCRIPTION: We present our experience with a 7-year-old patient of Lhermitte-Duclos disease who was followed up for 5 years and found to have progressed to bilateral World Health Organization grade IV medulloblastoma. This case denotes the malignant potential of this rare disorder. CONCLUSIONS: LDD is seen rarely and demands a high degree of suspicion in patients presenting with cerebellar mass and/or imaging characteristics. It is prudent to keep these patients in close follow-up for early detection of malignant transformation.

Hamartoma-like lesions in the mouse retina: an animal model of Pten hamartoma tumour syndrome.

PTEN hamartoma tumour syndrome (PHTS) is a heterogeneous group of rare, autosomal dominant disorders associated with PTEN germline mutations. PHTS patients routinely develop hamartomas, which are benign tissue overgrowths comprised of disorganized 'normal' cells. Efforts to generate PHTS animal models have been largely unsuccessful due to the early lethality of homozygous germline mutations in Pten, together with the lack of hamartoma formation in most conditional mutants generated to date. We report herein a novel PHTS mouse model that reproducibly forms hamartoma-like lesions in the central retina by postnatal day 21. Specifically, we generated a Pten conditional knockout (cKO) using a retinal-specific Pax6::Cre driver that leads to a nearly complete deletion of Pten in the peripheral retina but produces a mosaic of 'wild-type' and Pten cKO cells centrally. Structural defects were only observed in the mosaic central retina, including in Müller glia and in the outer and inner limiting membranes, suggesting that defective mechanical integrity partly underlies the hamartoma-like pathology. Finally, we used this newly developed model to test whether rapamycin, an mTOR inhibitor that is currently the only PHTS therapy, can block hamartoma growth. When administered in the early postnatal period, prior to hamartoma formation, rapamycin reduces hamartoma size, but also induces new morphological abnormalities in the Pten cKO retinal periphery. In contrast, administration of rapamycin after hamartoma initiation fails to reduce lesion size. We have thus generated and used an animal model of retinal PHTS to show that, although current therapies can reduce hamartoma formation, they might also induce new retinal dysmorphologies.This article has an associated First Person interview with the first author of the paper.

Combination vismodegib and photodynamic therapy for multiple basal cell carcinomas.

BACKGROUND: Oral vismodegib therapy and photodynamic therapy (PDT) are non-invasive treatments for basal cell carcinoma (BCC) with overlapping utility in widespread BCCs and patients who are poor surgical candidates. There is no published study to date investigating the combination use of PDT with vismodegib to optimize individual response rates. OBJECTIVE: To evaluate the combination of red light PDT and vismodegib therapy in patients with multiple nodular BCCs. The primary objective was to determine the safety of this combination therapy. Secondary outcomes included evaluation of the overall response rate, treatment-related pain, and cosmesis. METHODS: An open label pilot study of immunocompetent patients with multiple BCCs treated with 3 months of continuous vismodegib therapy (150 mg daily) and 3 consecutive ALA PDT sessions. Outcomes were assessed following each PDT session and 30 days post-treatment. RESULTS: Four patients with multiple nodular BCC (median=5) were enrolled in the trial between January and August of 2016. Three patients completed the full intervention phase trial and a total of 19 lesions were treated. One patient completed 2 months of vismodegib and 2 PDT sessions. One PDT session was sufficient for small lesions, whereas larger lesions required all 3 sessions. The fifteen evaluable lesions at the end of the 3 PDT sessions showed complete responses. At 30-day follow-up, one of the treated lesions was noted to have clinical evidence of disease. Overall response rate showed 90% complete response and 10% partial response for the study. Combination therapy was well tolerated and yielded a similar or superior side effect profile to that of individual therapies with excellent cosmesis. CONCLUSION: Combination PDT-vismodegib is a potential safe & effective therapy for the treatment of multiple BCCs that may enhance efficacy of individual therapies.

Cowden Syndrome with a Novel PTEN Mutation Presenting with Partial Epilepsy Related to Focal Cortical Dysplasia.

Cowden syndrome is a rare autosomal dominant disorder characterized by multiple hamartomas of the ectoderm and brain. A 36-year-old Japanese man presented with right facial seizure during sleep and was admitted to our hospital. He showed cobblestoning over the tongue and palmar pitting but no neurological abnormalities while he was not having a seizure. Brain magnetic resonance imaging showed focal cortical dysplasia in the left frontal lobe. Electroencephalography showed sharp waves over the left frontal lesion. A genetic analysis revealed a novel mutation of PTEN. The administration of carbamazepine ended the seizures. This is the first Japanese case of Cowden syndrome with a novel PTEN gene mutation and cortical dysplasia.

Infantile Lhermitte-Duclos Disease Treated Successfully With Rapamycin.

Lhermitte-Duclos disease is a rare hamartomatous tumor of the cerebellum resulting from a mutation in the phosphatase and tensin homolog (PTEN) gene: it has been reported in fewer than 10 infants. Rapamycin treatment has not yet been described in Lhermitte-Duclos disease. The infant underwent shunt placement shortly after birth for aqueductal stenosis. Her clinical progression included failure to thrive, seizures, episodes of decerebrate posturing, loss of respiratory drive, and pituitary insufficiency from mass effect. The characteristic "tiger stripe" sign on imaging prompted diagnosis. Rapamycin therapy was initiated at 18 months. Within 5 months, our patient has become responsive to her surroundings and had return of spontaneous breathing. Repeat magnetic resonance imaging (MRI) reveals lack of brainstem compression or distortion of pituitary stalk. Rapamycin should be considered in cases of Lhermitte-Duclos disease where surgical removal may not be an option, as in our case where the cerebellum was entirely involved.

JC virus granule cell neuronopathy in the setting of chronic lymphopenia treated with recombinant interleukin-7.

JC virus (JCV) is a human polyomavirus that infects the central nervous system (CNS) of immunocompromised patients. JCV granule cell neuronopathy (JCV-GCN) is caused by infection of cerebellar granule cells, causing ataxia. A 77-year-old man with iatrogenic lymphopenia presented with severe ataxia and was diagnosed with JCV-GCN. His ataxia and cerebrospinal fluid (CSF) improved with intravenous immunoglobulin, high-dose intravenous methylprednisolone, mirtazapine, and mefloquine. Interleukin-7 (IL-7) therapy reconstituted his lymphocytes and reduced his CSF JCV load. One month after IL-7 therapy, he developed worsening ataxia and CSF inflammation, which raised suspicion for immune reconstitution inflammatory syndrome. Steroids were restarted and his ataxia stabilized.

Cutaneous and ocular manifestations of neurocutaneous syndromes.

Neurocutaneous syndromes are a heterogeneous group of congenital and hereditary disorders with manifestations in the skin and the nervous system, usually together with ocular features that represent diagnostic clues and potential sources of morbidity. Dermatologists and ophthalmologists often need to work together in identifying and managing patients with these conditions; herein, we focus on classic and under-recognized neurocutaneous syndromes. We begin with autosomal dominant genodermatoses characterized by hamartomas and tumors in the skin, eyes, and central nervous system: neurofibromatosis type 1, tuberous sclerosis complex, and PTEN hamartoma-tumor syndrome. This is followed by a discussion of two mosaic disorders, Sturge-Weber syndrome and neurocutaneous melanocytosis. In addition to providing an update on clinical presentations and evaluation of patients with these conditions, we review recent insights into their pathogenesis, drawing attention to relationships among the diseases on a molecular level and implications regarding treatment. We also highlight the major features of other neurocutaneous syndromes that have ocular findings plus pigmentary, vascular, hyperkeratotic, adnexal, connective tissue, photosensitive, and inflammatory manifestations in the skin.