Accuracy of contrast-enhanced CT in liver neoplasms in children under 2 years age.

BACKGROUND: Multiple differentials exist for pediatric liver tumors under 2 years. Accurate imaging diagnosis may obviate the need for tissue sampling in most cases. OBJECTIVE: To evaluate the imaging features and diagnostic accuracy of computed tomography (CT) in liver tumors in children under 2 years. METHODS: Eighty-eight children under 2 years with treatment naive liver neoplasms and baseline contrast-enhanced CT were included in this institutional review board approved retrospective study. Two blinded onco-radiologists assessed these tumors in consensus. Findings assessed included enhancement pattern, lobulated appearance, cystic change, calcifications, central scar-like appearance, and metastases. The radiologists classified the lesion as hepatoblastoma, infantile hemangioma, mesenchymal hamartoma, rhabdoid tumor, or indeterminate, first based purely on imaging and then after alpha-fetoprotein (AFP) correlation. Multivariate analysis and methods of comparing means and frequencies were used for statistical analysis wherever applicable. Diagnostic accuracy, sensitivity, and positive predictive values were analyzed. RESULTS: The mean age of the sample was 11.4 months (95% CI, 10.9-11.8) with 50/88 (57%) boys. The study included 72 hepatoblastomas, 6 hemangiomas, 4 mesenchymal hamartomas, and 6 rhabdoid tumors. Presence of calcifications, multilobular pattern of arterial enhancement, lobulated morphology, and central scar-like appearance was significantly associated with hepatoblastomas (P-value < 0.05). Fourteen out of eighty-eight lesions were called indeterminate based on imaging alone; six lesions remained indeterminate after AFP correlation. Pure radiology-based diagnostic accuracy was 81.8% (95% CI, 72.2-89.2%), which increased to 92.1% (95% CI, 84.3-96.7%) (P-value > 0.05) after AFP correlation, with one hepatoblastoma misdiagnosed as a rhabdoid tumor. If indeterminate lesions were excluded for biopsy, the accuracy would be 98.8% (95% CI, 93.4-99.9%). CONCLUSION: CT had high accuracy for diagnosing liver neoplasms in the under 2-year age population after AFP correlation. Certain imaging features were significantly associated with the diagnosis of hepatoblastoma. A policy of biopsying only indeterminate lesions after CT and AFP correlation would avoid sampling in the majority of patients.

A Child With Recurrent Jaw Swelling.

A 9-year-old male presented with a 2-year history of recurrent left-sided jaw swelling. Physical examination revealed a hard mass at the left ramus of the mandible. What is your diagnosis?

The Great Imposter: An Atypical Case of Pleomorphic Adenoma With Review of Literature.

Pleomorphic adenomas (PA) are the most common type of salivary gland tumors. These slow-growing benign tumors most commonly involve the parotid gland, but can sometimes occur at atypical sites such as the submandibular or minor salivary glands. We describe an atypical case of pleomorphic adenoma with multicentric involvement of the parotid, the submandibular gland, and the parapharyngeal space in a 35-year-old male which mimicked a slow-flow malformation on magnetic resonance imaging (MRI). Diagnosis was confirmed on fine needle aspiration cytology, and conservative approach was opted for the patient in view of perioperative risks. This case highlights the uncommon multicentricity and atypical presentation of PA, challenging the initial differential diagnosis based on MRI features. It also underscores the importance of considering atypical presentations and utilizing accurate diagnostic tools like cytology for managing complex salivary gland tumors.

Epilepsia Partialis Continua as a Sequelae of Measles Infection in Children With Hematolymphoid Malignancies.

PURPOSE: To share our clinical experience with the diagnosis and management of children with hematolymphoid malignancies presenting with epilepsia partialis continua (EPC) as a sequelae of measles infection. MATERIALS AND METHODS: In December 2022, a series of children in our hemato-oncology unit presented with focal status epilepticus with no conclusive evidence pointing toward any underlying etiology. One such child had a typical measles rash a few weeks before the onset of this focal status epilepticus. After a series of cases with a similar presentation, a clinical pattern suspicious for measles became evident. cerebrospinal fluid polymerase chain reaction was positive for measles virus with measles immunoglobin M detected in the serum. This led to the diagnosis of measles inclusion-body encephalitis in a series of children who presented with EPC over a period of 3 months. EPC is a rare manifestation of measles that is seen only in immunocompromised patients. RESULTS: Among the 18 children reported in this series, only 10 had a history of rashes. The rash was mostly transient and elicited only on retrospective history taking. Five of the 18 children who did not lose consciousness during the prolonged seizure episode survived the disease but had residual neurologic sequelae. Among the 18 children, two were unimmunized and immunization status could not be confirmed in three other children. CONCLUSION: This case series highlights the threats posed by measles infection in children with cancer who are immunosuppressed because of the underlying disease and ongoing chemotherapy. Loss of herd immunity because of declining measles immunization rates secondary to vaccine hesitancy and COVID-19 lockdown pose a greater risk of measles infection and its complications for patients with deficient immune systems.

Unusually Unnerved.

A 47-year-old woman had left-sided facial weakness and swelling for 2 months. These symptoms developed after chemotherapy. What is your diagnosis?

Treatment outcomes and prognostic factors in children with hepatoblastoma using a risk-stratified approach.

BACKGROUND: Not all the significant progress made in the management of children with hepatoblastoma (HB) has translated into improved outcomes in limited-resource settings. There are limited data on outcomes in children with HB from India. METHODS: All patients diagnosed with HB between July 2013 and December 2020 were risk-stratified and treated as per International Liver Tumor Strategy Group (SIOPEL). Patients with standard-risk HB received cisplatin monotherapy and those with high-risk HB received alternating cycles of cisplatin and the combination of carboplatin plus doxorubicin. Data regarding demographic details, chemotherapy, surgery, liver transplantation, outcomes, prognostic factors, and toxicity were collected. RESULTS: Of 157 patients with HB, 117 (74%) were high risk, 31 (20%) were standard risk, and nine (6%) unknown. Patients with standard-risk disease had excellent outcomes, with 3-year event-free survival (EFS) and overall survival (OS) of 96% and 100%, respectively. Among high-risk HB, six underwent orthotopic liver transplantation of which four were alive at last follow-up. The 3-year EFS and OS of patients with high-risk disease was 56% and 66%, respectively. Outcomes of patients with PRETEXT IV (3-year EFS: 42%, 3-year OS: 50%) and metastatic disease (3-year EFS: 30%, 3-year OS: 50%) were dismal. Patients with serum alpha-fetoprotein (AFP) reduction greater than 90% following two courses of chemotherapy had favorable outcomes; 3-year EFS: 80% versus 58% (p = .013) and 3-year OS: 95% vs. 68% (p < .01). Only two (6%) of 31 patients with relapse/refractory HB were alive at a median follow-up of 36 months, and both had received salvage chemotherapy and surgery. CONCLUSIONS: While children with standard-risk HB had excellent outcomes, those with high-risk disease continue to do poorly. Serial monitoring of serum AFP values is a cost-effective and reliable predictor of outcomes. Orthotopic liver transplantation remains a viable option for inoperable disease in resource-limited settings as well.

CT-Based Screening for Pulmonary Metastases in Head and Neck Squamous Cell Cancers: Diagnostic Accuracy and Cost Comparison with PET-CECT.

This study's objective was to compare detection rates of radiograph, computed tomography (CT), and positron emission tomography-contrast-enhanced computed tomography (PET-CECT) for pulmonary metastasis/synchronous primary lung tumors in head and neck squamous cell cancer (HNSCC) and its association with clinico-radio-pathological factors. Our retrospective study included 837 HNSCC patients from January 2012 to December 2017. Lung nodules were characterized on CT as benign, indeterminate, and metastatic. The true detection rate and statistical significance of associated risk factors were calculated. Risk factors for metastasis were determined using univariate and multivariate logistic regression models. Seventy-five (8.9%) patients had pulmonary metastasis and 3 (0.3%) had second lung primary. Detection rate of pulmonary metastasis by CT was higher (sensitivity-97.3%, specificity-97.2%) as compared to radiograph (sensitivity 49% and specificity 89%). Correlation was found between pulmonary and extra-pulmonary metastasis and N classification (P = 0.01, P = 0.02) and positive low jugular node (P = 0.001, P = 0.001). Using PET-CECT in place of CT costed an extra outlay of 7,033,805 INR (95,551.85 USD) while detecting distant metastasis in only 4 (0.47%) extra cases. Chest CT is a useful pulmonary metastases screening tool in advanced HNSCC patients with reasonable imaging cost as compared to PET-CT.

Prognostic Significance of EMVI in Rectal Cancer in a Tertiary Cancer Hospital in India.

Background Presence of extramural venous invasion (EMVI) is a poor prognostic factor for rectal cancer as per literature. However, India-specific data are lacking. Aim The aim of the study is to determine the prognostic significance of EMVI in locally advanced rectal cancer on baseline MRI. Materials and Methods We retrospectively reviewed 117 MRIs of operable non-metastatic locally advanced rectal cancers in a tertiary cancer institute. Three dedicated oncoradiologists determined presence or absence of EMVI, and its length and thickness, in consensus. These patients were treated as per standard institutional protocols and followed up for a median period of 37 months (range: 2-71 months). Kaplan-Meier curves (95% CI) were used to determine disease-free survival (DFS), distant-metastases free survival (DMFS), and overall survival (OS). Univariate analysis was performed by comparing groups with log-rank test. Results EMVI positive cases were 34/114 (29%). More EMVI-positive cases developed distant metastasis compared with EMVI-negative cases (14/34-41% vs. 22/83-26%). The difference, however, was not statistically significant ( p = 0.146). After excluding signet-ring cell cancers ( n = 14), EMVI showed significant correlation with DMFS ( p = 0.046), but not with DFS or OS. The median thickness and length of EMVI was 6 and 14 mm, respectively in patients who developed distant metastasis, as compared with 5 and 11 mm in those who did not, although this difference was not statistically significant. Conclusion EMVI is a predictor of distant metastasis in locally advanced non-metastatic, non-signet ring cell rectal cancers. EMVI can be considered another high-risk feature to predict distant metastasis.

Imatinib-induced retroperitoneal fibrosis in a child with chronic myeloid leukemia: a case report.

A 12 year old boy with chronic myeloid leukemia (CML) presenting with bilateral pitting pedal edema and abdominal distension after about 41 months of imatinib therapy and was diagnosed to have retroperitoneal fibrosis (RPF) based on imaging and biopsy findings. He was found to have bilateral hydroureteronephrosis needing double-J stenting to the more severely affected right ureter. Imatinib was briefly interrupted and restarted later due to rising transcript levels and unavailability of other alternatives at that time which was later substituted by dasatinib once generic versions became available. Child remains asymptomatic after 18 months of DJ stenting. RPF is a rare complication of imatinib this being the second case reported in the literature.

Probing the Mec1ATR Checkpoint Activation Mechanism with Small Peptides.

Yeast Mec1, the ortholog of human ATR, is the apical protein kinase that initiates the cell cycle checkpoint in response to DNA damage and replication stress. The basal activity of Mec1 kinase is activated by cell cycle phase-specific activators. Three distinct activators stimulate Mec1 kinase using an intrinsically disordered domain of the protein. These are the Ddc1 subunit of the 9-1-1 checkpoint clamp (ortholog of human and Schizosaccharomyces pombe Rad9), the replication initiator Dpb11 (ortholog of human TopBP1 and S. pombe Cut5), and the multifunctional nuclease/helicase Dna2. Here, we use small peptides to determine the requirements for Mec1 activation. For Ddc1, we identify two essential aromatic amino acids in a hydrophobic environment that when fused together are proficient activators. Using this increased insight, we have been able to identify homologous motifs in S. pombe Rad9 that can activate Mec1. Furthermore, we show that a 9-amino acid Dna2-based peptide is sufficient for Mec1 activation. Studies with mutant activators suggest that binding of an activator to Mec1 is a two-step process, the first step involving the obligatory binding of essential aromatic amino acids to Mec1, followed by an enhancement in binding energy through interactions with neighboring sequences.

The unstructured C-terminal tail of yeast Dpb11 (human TopBP1) protein is dispensable for DNA replication and the S phase checkpoint but required for the G2/M checkpoint.

Budding yeast Dpb11 (human TopBP1, fission yeast Cut5) is an essential protein required for replisome assembly and for the DNA damage checkpoint. Previous studies with the temperature-sensitive dpb11-1 allele, truncated at amino acid 583 of the 764-amino acid protein, have suggested the model that Dpb11 couples DNA replication to the replication checkpoint. However, the dpb11-1 allele shows distinct replication defects even at permissive temperatures. Here, we determine that the 1-600-amino acid domain of DPB11 is both required and sufficient for full replication function of Dpb11 but that this domain is defective for activation of the principal checkpoint kinase Mec1 (human ataxia telangiectasia and Rad3-related) in vitro and in vivo. Remarkably, mutants of DPB11 that leave its replication function intact but abrogate its ability to activate Mec1 are proficient for the replication checkpoint, but they are compromised for the G(2)/M DNA damage checkpoint. These data suggest that replication checkpoint defects may result indirectly from defects in replisome assembly. Two conserved aromatic amino acids in the C terminus of Dpb11 are critical for Mec1 activation in vitro and for the G(2)/M checkpoint in yeast. Together with aromatic motifs identified previously in the Ddc1 subunit of 9-1-1, another activator of Mec1 kinase, they define a consensus structure for Mec1 activation.

Cell-cycle-specific activators of the Mec1/ATR checkpoint kinase.

Mec1 [ATR (ataxia telangiectasia mutated- and Rad3-related) in humans] is the principle kinase responsible for checkpoint activation in response to replication stress and DNA damage in Saccharomyces cerevisiae. The heterotrimeric checkpoint clamp, 9-1-1 (checkpoint clamp of Rad9, Rad1 and Hus1 in humans and Ddc1, Rad17 and Mec3 in S. cerevisiae; Ddc1-Mec3-Rad17) and the DNA replication initiation factor Dpb11 (human TopBP1) are the two known activators of Mec1. The 9-1-1 clamp functions in checkpoint activation in G1- and G2-phase, but its employment differs between these two phases of the cell cycle. The Ddc1 (human Rad9) subunit of the clamp directly activates Mec1 in G1-phase, an activity identified only in S. cerevisiae so far. However, in G2-phase, the 9-1-1 clamp activates the checkpoint by two mechanisms. One mechanism includes direct activation of Mec1 by the unstructured C-terminal tail of Ddc1. The second mech-anism involves the recruitment of Dpb11 by the phosphorylated C-terminal tail of Ddc1. The latter mechanism is highly conserved and also functions in response to replication stress in higher eukaryotes. In S. cerevisiae, however, both the 9-1-1 clamp and the Dpb11 are partially redundant for checkpoint activation in response to replication stress, suggesting the existence of additional activators of Mec1.

The unstructured C-terminal tail of the 9-1-1 clamp subunit Ddc1 activates Mec1/ATR via two distinct mechanisms.

DNA damage checkpoint pathways operate to prevent cell-cycle progression in response to DNA damage and replication stress. In S. cerevisiae, Mec1-Ddc2 (human ATR-ATRIP) is the principal checkpoint protein kinase. Biochemical studies have identified two factors, the 9-1-1 checkpoint clamp and the Dpb11/TopBP1 replication protein, as potential activators of Mec1/ATR. Here, we show that G1 phase checkpoint activation of Mec1 is achieved by the Ddc1 subunit of 9-1-1, while Dpb11 is dispensable. However, in G2, 9-1-1 activates Mec1 by two distinct mechanisms. One mechanism involves direct activation of Mec1 by Ddc1, while the second proceeds by Dpb11 recruitment mediated through Ddc1 T602 phosphorylation. Two aromatic residues, W352 and W544, localized to two widely separated, conserved motifs of Ddc1, are essential for Mec1 activation in vitro and checkpoint function in G1. Remarkably, small peptides that fuse the two tryptophan-containing motifs together are proficient in activating Mec1.

A tale of two tails: activation of DNA damage checkpoint kinase Mec1/ATR by the 9-1-1 clamp and by Dpb11/TopBP1.

The DNA damage and replication checkpoint kinase Mec1/ATR is a member of the PI3-kinase related kinases that function in response to various genotoxic stresses. The checkpoint clamp 9-1-1 (Rad9-Rad1-Hus1 in S. pombe and mammals; Ddc1-Rad17-Mec3 in S. cerevisiae) executes two distinct checkpoint functions. In S. cerevisiae, DNA-bound 9-1-1 directly activates Mec1 kinase activity, a function that has not been demonstrated in other organisms. A second, conserved activity of 9-1-1 is that of TopBP1/Cut5/Dpb11 recruitment to stalled replication sites; subsequent activation of Mec1/ATR is carried out by TopBP1/Cut5/Dpb11. Biochemical studies indicate that the mode of Mec1/ATR activation by S. cerevisiae 9-1-1 is analogous to activation by S. cerevisiae Dpb11 or by vertebrate TopBP1: activation is mediated by the intrinsically disordered C-terminal tail of each activator. The relative contributions made by multiple activators of Mec1/ATR are discussed.

Yeast DNA replication protein Dpb11 activates the Mec1/ATR checkpoint kinase.

The Saccharomyces cerevisiae Mec1-Ddc2 protein kinase (human ATR-ATRIP) initiates a signal transduction pathway in response to DNA damage and replication stress to mediate cell cycle arrest. The yeast DNA damage checkpoint clamp Ddc1-Mec3-Rad17 (human Rad9-Hus1-Rad1: 9-1-1) is loaded around effector DNA and thereby activates Mec1 kinase. Dpb11 (Schizosaccharomyces pombe Cut5/Rad4 or human TopBP1) is an essential protein required for the initiation of DNA replication and has a role in checkpoint activation. In this study, we demonstrate that Dpb11 directly activates the Mec1 kinase in phosphorylating the downstream effector kinase Rad53 (human Chk1/2) and DNA bound RPA. However, DNA was not required for Dpb11 to function as an activator. Dpb11 and yeast 9-1-1 independently activate Mec1, but substantial synergism in activation was observed when both activators were present. Our studies suggest that Dpb11 and 9-1-1 may partially compensate for each other during yeast checkpoint function.