Dual-phase computed tomography for localization of parathyroid lesions in children and adolescents with primary hyperparathyroidism.

BACKGROUND: Childhood and adolescent primary hyperparathyroidism (PHPT) is a rare disease caused by single adenomas in 65-94% of patients. In this patient group, there is no data on computed tomography (CT) for pre-operative parathyroid localization that may facilitate focused parathyroidectomy. METHODS: Two radiologists reviewed dual-phase (nonenhanced and arterial) CT images of twenty-three operated children and adolescents [20:single-gland disease(SGD), 3:multi-glandular disease(MGD)] with proven histopathological PHPT. Percentage arterial enhancement (PAE) was calculated as [100*{arterial-phase Hounsfield unit (HU)-nonenhanced phase HU}/nonenhanced HU] of the parathyroid lesion(s), thyroid, and lymph node. RESULTS: Dual-phase CT lateralized 100%, localized to the correct quadrant/site 85% SGD (including 3/3 ectopic), and identified 1/3 MGD. PAE (cutoff ≥ 112.3%) was sensitive (91.3%) and specific (99.5%) in distinguishing parathyroid lesions from local mimics (P<0.001). The average effective dose was 3.16±1.01mSv, comparable to the planar/single photon emission CT (SPECT) Technetium 99m(Tc)-sestamibi and choline positron emission tomography (PET)/CT scans. Solid-cystic morphology identified in 4 patients harboring pathogenic germline variants (3:CDC73, 1:CASR) may serve as a radiological clue to molecular diagnosis. Nineteen out of 20 (95%) patients with SGD who had undergone single gland resection based on pre-operative CT findings were in remission over a median follow-up of 18 months. CONCLUSION: As most children/adolescents with PHPT have SGD, dual-phase CT protocols which reduce the effective radiation dose with high localization sensitivity for single parathyroid lesions may be a sustainable pre-operative imaging modality in this patient group.

Genetic spectrum of Kallmann syndrome: Single-center experience and systematic review.

OBJECTIVE: To study phenotype-genotype data of Asian-Indian Kallmann syndrome (KS) from our center and systematically review the studies analyzing multiple congenital hypogonadotropic hypogonadism (CHH) genes in KS cohorts using next-generation sequencing. DESIGN, PATIENTS, MEASUREMENT: Five hundred twenty-two KS probands (our center n = 78, published studies n = 444) were included in this systematic review. Molecular diagnosis was considered if the likely pathogenic/pathogenic variant in known CHH gene/s was reported in the appropriate allelic state. Varsome prediction tool (following American College of Medical Genetics standards) was used to analyze the variants. RESULT: For our center, the molecular diagnosis was seen in 20.5% of probands and was seen more often with severe than partial reproductive phenotype (28.3% vs. 4%, p = .0013). Our center data adds eight novel variants. The molecular diagnosis was seen in 31% as per the systematic review and analysis. It ranged from 16.6% to 72.2% at different centers. The affected genes were FGFR1 (9.8%), ANOS1 (7.5%), PROKR2 (6.1%), CHD7 (5.4%), oligogenic (2.1%), and others <1% each (FGF8, SOX10, PROK2, SEMA3A, IL17RD, and GNRHR). FGFR1 and ANOS1 were the commonly affected genes globally, whereas PROKR2 was commonest in studies from China and CHD7 from Japan, South Korea and Poland. CONCLUSION(S): This systematic review highlights that the genetic yield is 31% in KS probands, with distinct regional variations. The association of severe reproductive phenotype with the higher genetic yield needs further validation.

Percentage arterial enhancement on 2D CT in the diagnosis of primary hyperparathyroidism: A prospective validation study and potential pitfalls.

BACKGROUND: Parathyroid lesions are identified by subjective enhancement and washout patterns on computed tomography (CT). We have previously proposed "percentage arterial enhancement" (PAE) as an objective index and now aim to validate its performance prospectively. METHODS: Dual-phase CT was performed in 40 consecutive primary hyperparathyroidism patients. PAE was calculated as [{arterial phase Hounsfield unit (HU)-unenhanced phase HU}/unenhanced phase HU] × 100. PAE > 128.9% was considered parathyroid. RESULTS: PAE had 94.2% sensitivity, 100% positive predictive value (PPV) in lateralization, and sensitivity and PPV of 93.9% in quadrant localization of single-gland disease. PAE failed to identify two lesions: an intrathyroidal parathyroid carcinoma in the background of multinodular goiter and another lower enhancing cystic parathyroid adenoma. PAE had 60% sensitivity, and 100% PPV to identify multigland disease. The mean effective dose was 2.74 mSV. CONCLUSIONS: PAE is a specific CT index for parathyroid lesions with less radiation exposure. Areas of caution include intrathyroidal and cystic lesions.

Genotype-Phenotype Correlations in Asian Indian Children and Adolescents with Primary Hyperparathyroidism.

Childhood and adolescent primary hyperparathyroidism (PHPT) is a very rare disease. Data on its molecular genetics are scarce. We performed a retrospective analysis (January 2000-January 2021) to determine the deleterious germline variants and genotype-phenotype correlations in children and adolescents < 20 years diagnosed with PHPT from a single referral center. Clinical features, biochemistry, imaging, management, and genetics (clinical exome analyzed for 11 PHPT and 7 pancreatitis-associated genes, MLPA for CDC73) were recorded. Thirty-six patients (20 males; median age 17 years) were classified into those with familial and/or syndromic (F/S) or apparently sporadic (AS) presentation. Sixteen (44.4%) harbored pathogenic/likely pathogenic germline variants in PHPT-associated genes. The genetic yield in F/S group was 90% (MEN1:8/10; CDC73:1/10), and AS group was 26.9% (CDC73:4/26; CASR:3/26). F/S group had frequent asymptomatic presentation (60% vs none; P < 0.001), lower serum PTH (237.5 vs 1369.1 pg/mL; P = 0.001), and maximum parathyroid dimension (0.9 vs 2.2 cm; P = 0.01) than AS group. Among the AS group, renal involvement was higher in those with molecular diagnoses (71.4% vs 10.5%; P = 0.01). All those with novel CASR variants (including one homozygous) had hypercalciuria and histology-proven parathyroid adenoma/carcinoma. A missense CTRC VUS occurred in one patient with chronic pancreatitis. In summary, Asian Indian children and adolescents with PHPT have high genetic yield, even with apparently sporadic presentation. The phenotypic spectrum of CASR variants is expanded to include childhood/adolescent PHPT with hypercalciuria and single gland neoplasia. The proposed roles for renal involvement to predict molecular diagnosis among those with apparently sporadic presentation require further elucidation.

Regional genotypic variations in normosmic congenital hypogonadotropic hypogonadism: our experience and systematic review.

PURPOSE: To describe phenotype-genotype data of Asian-Indian normosmic congenital hypogonadotropic hypogonadism (nCHH) from our centre and perform a systematic review of genetic studies using next-generation sequencing (NGS) in nCHH. METHODS: Sixty-eight nCHH probands from our center, and 370 nCHH probands from published studies were included. Per-patient genetic variants were analyzed as per ACMG guidelines. Molecular diagnosis was defined as presence of a pathogenic or likely pathogenic variant in a known CHH gene following zygosity status as per known mode of genetic inheritance. RESULT: At our centre molecular diagnosis was observed in 35.3% of probands {GNRHR:16.2%, FGFR1:7.3%, KISS1R:4.4%, GNRH1:2.9%, TACR3:2.9%, CHD7:1.4%}. Molecular diagnosis was observed more often (44.7% vs 14.3%, p = 0.026) with severe than partial reproductive-phenotype. The study adds 12 novel variants and suggests GNRHR p.Thr32Ala variant may have a founder effect. In per-patient systematic review (including our cohort), the molecular diagnosis was reached in 23.2%, ranging from 3.5 to 46.7% at different centers. The affected genes were FGFR1:6.4%, GNRHR:4.3%, PROKR2:3.6%, TACR3:1.8%, CHD7:1.6%, KISS1R:1.4%, GNRH1:1.4% and others (PROK2, SOX3, SOX10, SOX11, IL17RD, IGSF10, TAC3, ANOS1, oligogenic): < 1% each. FGFR1 was the most commonly affected gene in most cohorts except Asia, whereas PROKR2 (in China and Japan) and GNRHR (in India) were the commonest. CONCLUSION: (s): The global molecular diagnosis rate was 23.2% in nCHH cohorts whereas that in our cohort was 35% with a higher rate (44.7%) in those with severe reproductive-phenotype. The most commonly affected gene in nCHH patients was FGFR1 globally while it was PROKR2 in East Asia and GNRHR in India.

Homozygous p.Val89Leu plays an important pathogenic role in 5α-reductase type 2 deficiency patients with homozygous p.Arg246Gln in SRD5A2.

OBJECTIVE: To evaluate the pathogenic role of a few benign variants and hypomorphic pathogenic variants in SRD5A2. DESIGN AND METHODS: We retrospectively analyzed phenotypes and genotypes in 23 Indian patients with genetically proven steroid 5α-reductase 2 (SRD5A2) deficiency. The interactions of the SRD5A2 enzymes resulting due to the most common benign variant (p.Val89Leu), the most common (hypomorphic) pathogenic variant (p.Arg246Gln) and the double variants (p.Val89Leu and p.Arg246Gln) in SRD5A2 were compared with that of the wild type (WT) enzyme by molecular dynamics (MD) simulation. RESULTS: The majority (n = 19, 82.61%) of patients presented for atypical genitalia and had male gender identity (16/20). Including the two novel ones (p.Leu83Pro, p.Ala28Leufs*103), a total of nine different pathogenic variants were observed. p.Arg246Gln was the most common pathogenic variant (n = 12). Homozygous p.Arg246Gln (n = 9) variant was associated with milder undervirilization (Sinnecker score of ≤3a: 8/9 vs 6/14, P = 0.04) and had concurrent homozygous p.Val89Leu in all patients. Interestingly, asymptomatic fathers of two index patients were homozygous for p.Arg246Gln which questioned the pathogenicity of the variation as a sole factor. Unlike all symptomatic homozygous p.Arg246Gln patients who were also homozygous for p.Val89Leu, asymptomatic homozygous p.Arg246Gln fathers were heterozygous for p.Val89Leu. On MD simulation SRD5A2 p.Val89Leu-Testeosterone (T) and SRD5A2 p.Arg246Gln-T complexes, but not SRD5A2 p.Val89Leu and p.Arg246Gln-T complex, demonstrated close interaction between NADPH and T as that of SRD5A2 WT-T. CONCLUSIONS: p.Arg246Gln may not be pathogenic as a sole variation even in the homozygous state; additional contribution of homozygous p.Val89Leu variant may be essential for the pathogenicity of p.Arg246Gln in SRD5A2.

Radiological differentiation of phaeochromocytoma from other malignant adrenal masses: importance of wash-in characteristics on multiphase CECT.

Rationale and introduction: To evaluate the computerised tomography (CT) characteristics of phaeochromocytoma (PCC) that differentiate them from other non-benign adrenal masses such as adrenocortical carcinoma (ACC), primary adrenal lymphoma (PAL) and adrenal metastases (AM). Methods: This retrospective study was conducted at a tertiary health care institute from Western India. Patients presented between January 2013 and August 2016 with histological diagnosis of PCC or other non-benign adrenal mass having adequate reviewable imaging data comprising all four CECT phases were included. Results: The study cohort consisted of 72 adrenal masses from 66 patients (33 PCC, 22 ACC, 4 PAL, 13 AM). Unlike other masses, majority of PCC (25/33) showed peak enhancement in early arterial phase (EAP). PCC had significantly higher attenuation in EAP and early venous phase (EVP), and higher calculated percentage arterial enhancement (PAE) and percentage venous enhancement (PVE) than other adrenal masses (P < 0.001). For diagnosis of PCC with 100% specificity, PAE value ≥100% and EAP attenuation ≥100 HU had 78.8 and 63.6% sensitivity respectively. ACC were significantly larger in size as compared to PCC and metastasis. The adreniform shape was exclusively found in PAL (two out of four) and AM (4 out of 13). None of the enhancement, wash-in or washout characteristics were discriminatory among ACC, PAL and AM. Conclusion: Peak enhancement in EAP, PAE value ≥100% and EAP attenuation ≥100 HU differentiate PCC from other malignant adrenal masses with high specificity.

Percentage arterial enhancement: An objective index for accurate identification of parathyroid adenoma/hyperplasia in primary hyperparathyroidism.

BACKGROUND: Radiation exposure to neck by four-dimensional computerized tomography (4DCT) is relatively high and limits its use as a first-line investigation in evaluation of primary hyperparathyroidism (PHPT). Radiation exposure can be reduced by restricting the number of CT phases. Our aim was to study the performance of 4DCT in cohort of surgery-naïve PHPT patients, and to evaluate percentage enhancement as an objective radiological index to discriminate parathyroid lesions (adenoma/hyperplasia) from thyroid tissue and lymph nodes. MATERIALS AND METHOD: Retrospective study of 49 PHPT patients {(44 single-gland diseases (SGD) and five multiple-gland disease (MGD)} who underwent 4DCT (unenhanced, early arterial, early venous and delayed venous phase) pre-operatively. Two radiologists who were blinded to surgical location of parathyroid lesions examined the scans. Attenuation values were recorded for parathyroid lesions (n=50), thyroid gland (n=50) and lymph nodes (n=12) in different phases. Percentage enhancement for different phases was calculated as "(HU in a specific enhanced phase-HU in unenhanced phase)/HU in unenhanced phase" ×100. RESULTS: Inter-rater reliability between the two radiologists was 0.83 (Cohen's kappa). In SGD, sensitivity and PPV were 93.18% and 98.8% for lateralization, and 89.77% and 95.18% for quadrant localization, respectively. In MGD, 4DCT showed 50% sensitivity and 100% PPV. Percentage arterial enhancement showed highest area under curve (AUC=0.992) for differentiation of parathyroid lesions from thyroid tissue and lymph nodes. A cut-off value of 128.9% showed 95.8% sensitivity and 100% specificity for the identification of parathyroid lesions. CONCLUSIONS: We propose that percentage arterial enhancement can be used as an objective radiological index for accurate identification of parathyroid adenoma/hyperplasia.

Comparison of 68Ga-DOTANOC PET/CT and contrast-enhanced CT in localisation of tumours in ectopic ACTH syndrome.

BACKGROUND: Localising ectopic adrenocorticotrophic hormone (ACTH) syndrome (EAS) tumour source is challenging. Somatostatin receptor-based PET imaging has shown promising results, but the data is limited to case reports and small case series. We reviewed here the performance of (68)Ga-DOTANOC positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) in our cohort of 12 consecutive EAS patients. MATERIALS AND METHODS: Retrospective data analysis of 12 consecutive patients of EAS presenting to a single tertiary care centre in a period between January 2013 and December 2014 was done. CECT and (68)Ga-DOTANOC PET/CT were reported (blinded) by an experienced radiologist and a nuclear medicine physician, respectively. The performance of CECT and (68)Ga-DOTANOC PET/CT was compared. RESULTS: Tumours could be localised in 11 out of 12 patients at initial presentation (overt cases), whereas in one patient, tumour remained occult. Thirteen lesions were identified in 11 patients as EAS source (true positives). CECT localised 12 out of these 13 lesions (sensitivity 92.3%) and identified five false-positive lesions (positive predictive value (PPV) 70.5%). Compared with false-positive lesions, true-positive lesions had greater mean contrast enhancement at 60s (33.2 vs 5.6 Hounsfield units (HU)). (68)Ga-DOTANOC PET/CT was able to identify 9 out of 13 lesions (sensitivity 69.2%) and reported no false-positive lesions (PPV 100%). CONCLUSION: CECT remains the first-line investigation in localisation of EAS. The contrast enhancement pattern on CECT can further aid in characterisation of the lesions. (68)Ga-DOTANOC PET/CT can be added to CECT, to enhance positive prediction of the suggestive lesions.

The performance and reproducibility of late-night salivary cortisol estimation by enzyme immunoassay for screening Cushing disease.

OBJECTIVE: Our study aimed to establish a local reference range for late-night salivary cortisol (LNSC) using enzyme immunoassay (EIA) and to study the intra-individual reproducibility of LNSC. METHODS: Prospective study involving 30 healthy subjects (HS) with body mass index (BMI) <25 kg/m2, 37 obese/overweight subjects (OS) with BMI >25 kg/m2 and 28 patients with Cushing disease (CD). Salivary sampling was performed on 2 consecutive nights and assayed by EIA. The reference range was established using LNSC values of HS, and receiver operating characteristic (ROC) curves were used to determine diagnostic cutoffs. RESULTS: The mean LNSC level of CD was significantly higher than HS and OS (CD: 16.96 ± 9.11 nmol/L, HS: 1.30 ± 0.95 nmol/L, and OS 1.21 ± 0.78 nmol/L). A cutoff of 2.92 nmol/L differentiated CD from HS with 100% sensitivity and 96.7 % specificity, and a cutoff of 5.04 nmol/L yielded a specificity of 100% with a sensitivity of 96.4% to distinguish CD from OS. There was more intra-individual variability in HS (55%) than in CD (49%) and OS (22%). There was no difference in the sensitivity and specificity derived from the ROCs using day 1 values or the higher of the 2 LNSCs. CONCLUSIONS: In our cohort, we found that LNSC assayed by EIA showed good sensitivity and specificity to screen patients suspected to have CD. Although intra-individual variability was significant, it did not hamper the diagnostic performance of the test.