A New de novo Mosaic Mutation of PHEX Gene: A Case Report of a Boy with Hypophosphatemic Rickets.

BACKGROUND: X-linked hypophosphatemia is the most prevalent form of heritable rickets, characterized by an X-linked dominant inheritance pattern. The genetic basis of X-linked hypophosphatemia is a loss-of-function mutation in the PHEX gene (Phosphate regulating gene with Homology to Endopeptidases on the X chromosome), which leads to an enhanced production of phosphaturic hormone FGF23. X-linked hypophosphatemia causes rickets in children and osteomalacia in adults. Clinical manifestations are numerous and variable, including slowdown in growth, swing-through gait and progressive tibial bowing, related to skeletal and extraskeletal actions of FGF23. PHEX gene spans over 220 kb and consists of 22 exons. To date, hereditary and sporadic mutations are known (missense, nonsense, deletions and splice site mutations). CASE PRESENTATION: Herein, we describe a male patient carrying a novel de novo mosaic nonsense mutation c.2176G>T (p.Glu726Ter) located in exon 22 of PHEX gene. CONCLUSION: We highlight this new mutation among possible causative of X-linked hypophosphatemia and suggest that mosaicism of PHEX mutations is not so uncommon and should be excluded in diagnostic workflow of heritable rickets both in male and female patients.

Calcium-stimulated calcitonin test for the diagnosis of medullary thyroid cancer: results of a multicenter study and comparison between different assays.

BACKGROUND: A basal serum calcitonin (Ct) increase >100 pg/mL in patients with a thyroid nodule is consistent with the diagnosis of medullary thyroid cancer (MTC). In cases where the CT test have a slight to moderate increase, the calcium gluconate stimulation test is helpful to increase diagnostic accuracy. However, reliable cut-offs for calcium-stimulated Ct are still lacking. The aim of this study was to evaluate the sex-specific calcium-stimulated Ct cutoffs for the diagnosis of MTC in a multicenter series. A comparison between different Ct assays has been also performed. METHODS: 90 subjects undergone calcium-stimulated Ct for a suspected MTC in 5 Endocrine Units between 2010-2021 were retrospectively analyzed. Serum Ct concentrations were assessed by immunoradiometric (IRMA) or chemiluminescence (CLIA) assays. RESULTS: MTC was diagnosed in 37 (41.1%) and excluded in 53 (58.9%) patients. The best calcium-stimulated Ct cut-off to identify MTC was 611 pg/mL in males (AUC =0.90, 95% CI (0.76;1) and 445 pg/mL in females (AUC=0.79, 95% CI (0.66;0.91). Logistic regression analysis showed that both basal (OR 1.01, P=0.003) and peak Ct after stimulation (OR 1.07, P=0.007) were significantly associated with MTC, together with sex (OR=0.06, P<0.001). The "Ct assay" variable was also considered in the logistic regression model, but it was not significantly associated with MTC (OR=0.93, P=0.919). CONCLUSIONS: This study indicates that calcium test could be helpful to identify patients with early-stage MTC and those without MTC. A Ct value of 611 pg/mL in males and 445 pg/mL in females are proposed as the optimal Ct cut-offs at the stimulation test.

Decreased serum vascular endothelial growth factor-D levels in metastatic patients with differentiated thyroid carcinoma.

OBJECTIVE: Vascular endothelial growth factor-D (VEGF-D) has been identified as one of the lymphangiogenic growth factors involved in metastatic diffusion. The aim of this study is to evaluate the serum VEGF-D levels in patients with differentiated thyroid cancer at different conditions of disease. DESIGN AND PATIENTS: We studied prospectively the VEGF-D plasma levels in 96 subjects affected by differentiated thyroid cancer. The patients were divided into three groups according to the clinical and biochemical findings: patients with no evidence of disease (Cured), patients with pathological (>1 ng/ml) stimulated thyroglobulin (Tg) (Path-Tg/rhTSH) levels only after rhTSH and patients with elevated basal Tg levels (Path-Tg/LT4). RESULTS: The serum VEGF-D concentrations in patients of group Cured were not different from the controls, while group Path-Tg/rhTSH showed baseline serum VEGF-D levels significantly lower than group Cured and controls (P < 0·001 and P < 0·01, respectively). Moreover, the patients of group Path-Tg/LT4 showed median serum cytokine concentrations at baseline not significantly different from the patients of group Path-Tg/rhTSH. The rhTSH stimulation did not modify the difference in serum VEGF-D levels in patients of group Cured and group Path-Tg/rhTSH. CONCLUSIONS: Our data demonstrate that the VEGF-D serum levels are reduced in patients with metastases of differentiated thyroid cancer, regardless of the degree of metastatic spread. It is possible that some other molecule produced by the tumoral tissue could affect the VEGF-D physiologically produced of from different tissues, thus conducting to a decrease in the VEGF-D found in blood of patients with evidence of metastatic differentiated thyroid cancer.

Combination of Lenvatinib and Pembrolizumab as Salvage Treatment for Paucicellular Variant of Anaplastic Thyroid Cancer: A Case Report.

Anaplastic thyroid cancer (ATC) is a rare but aggressive thyroid cancer, responsible for about 50% of all thyroid cancer-related deaths. During the last two decades, the development of a multimodal personalized approach resulted in an increased survival. Here, we present an unusual case of a 54-year old woman with a paucicellular metastatic ATC, a rare variant of ATC, who was treated with a combination of surgery, radiation therapy and cytotoxic chemotherapy. More than two years later, when the disease was rapidly growing, a combination of lenvatinib and pembrolizumab induced a partial tumor response of lung metastasis that persisted over 18 months. Paucicellular ATC may initially show a less aggressive behavior compared to other histological ATC variants. However, over the time, its clinical course can rapidly progress like common ATC. The combination of lenvatinib and pembrolizumab was effective as a salvage therapy for a long period of time.

Evaluation of BRAF, RAS, RET/PTC, and PAX8/PPARg alterations in different Bethesda diagnostic categories: A multicentric prospective study on the validity of the 7-gene panel test in 1172 thyroid FNAs deriving from different hospitals in South Italy.

BACKGROUND: Thyroid fine-needle aspiration (FNA) is a reliable and cost-effective diagnostic tool for establishing the nature of thyroid nodules, although up to 30% of FNAs are still classified as "indeterminate." Molecular testing of FNAs could improve preoperative diagnosis, thereby reducing unnecessary surgery. In this multicenter prospective study the authors investigated, using a 7-gene assay, the distribution and diagnostic impact of BRAF, RAS, RET/PTC, and PAX8/PPARg, the most frequent genomic alterations occurring during thyroid oncogenesis. METHODS: In total, of 1172 routine FNAs from 7 centers in southern Italy were classified according to the Bethesda System for Reporting Thyroid Cytopathology. Each specimen was tested, and molecular data were compared with available histology or cytologic follow-up. RESULTS: In particular, for atypia of undetermined significance/follicular lesion of undetermined significance cases, the 7-gene test confirmed the high positive predictive value of BRAFV600E and BRAF-like mutations (80%) and the moderate positive predictive value of RAS-like alterations (32.4%), suggesting different surgical management, depending on the type of mutation. The rate of mutation-positive FNAs was strictly related to the risk of malignancy of each diagnostic class, supporting the identification of prognostically relevant diagnostic categories. CONCLUSIONS: The 7-gene panel test improves the preoperative risk stratification of indeterminate thyroid FNAs, especially when considering the biologic significance of the different types of mutations. Moreover, the rate of mutation-positive FNAs is related to the risk of malignancy of each diagnostic class.