Publications by authors named "Char-Loo Tan"

Background And Purpose: Evidence and clinical guidelines support the use of adjuvant RT in high-risk low-grade gliomas. However, patients with oligodendroglioma have a more indolent disease course and delaying or avoiding RT is often considered to reduce treatment-related toxicities. As the optimal adjuvant management for oligodendroglioma is unclear, we aimed to assess the effect of adjuvant RT on overall survival (OS) and progression-free survival (PFS).

View Article and Find Full Text PDF
Article Synopsis
  • AI solutions for Gleason grading show potential for pathologists, but face challenges like inconsistent image quality and limited adaptability to different data sources.
  • The proposed digital pathology workflow includes AI-driven components for image quality control, cloud annotation, and ongoing model improvements, achieving promising results across various scanner types.
  • The model notably improves Gleason scoring speed by 43% and enhances accuracy, making it a significant step towards integrating AI in clinical practices for better diagnostic consistency.
View Article and Find Full Text PDF
Article Synopsis
  • ChatGPT, an AI chatbot from OpenAI, was assessed for its effectiveness in diagnostic histopathology compared to human pathologists in a study that examined its collaborative potential.* -
  • The study revealed that ChatGPT's diagnostic accuracy was inferior to that of pathologists, and while its responses depended on the quality of prompts, it provided limited assistance in diagnosing cases.* -
  • Despite its shortcomings, pathologists acknowledged ChatGPT's utility as an advanced search tool, suggesting that future improvements in AI could enhance its role in histopathology.*
View Article and Find Full Text PDF

Ependymomas are glial neoplasms with a wide morphological spectrum. The majority of supratentorial ependymomas are known to harbor fusions, most commonly to . We present an unusual case of a 9-year-old boy with a supratentorial ependymoma harboring a noncanonical fusion.

View Article and Find Full Text PDF

Angiomatoid fibrous histiocytoma (AFH) is an uncommon soft tissue neoplasm that can exhibit diverse morphological features, including myxoid change. Rarely, the tumor occurs intracranially and poses considerable diagnostic challenges to neuropathologists. This is compounded by a recently coined entity, referred to as intracranial myxoid mesenchymal tumor (IMMT).

View Article and Find Full Text PDF

Implant exposure is a known complication of titanium mesh cranioplasty and is usually managed by implant removal and/or exchange. We describe a case of exposed titanium mesh cranioplasty which was managed with implant exchange and bipedicled flap coverage, and showcase an interesting phenomenon of full-thickness skin present beneath the exposed mesh. This was confirmed on histopathology, which showed the presence of dermal appendages including pilosebaceous units and eccrine glands.

View Article and Find Full Text PDF

Introduction: The differential diagnoses for multifocal lesions with pineal and suprasellar involvement in a young adult include germ cell tumour and intracranial metastasis. Other differentials include atypical teratoid/rhabdoid tumour and pineoblastoma. We present the first known case of multicentric H3K27M mutant diffuse midline glioma, which is typically defined by its diffuse nature, midline location, and H3K27M mutation.

View Article and Find Full Text PDF

MN1 alteration characterizes a recently described group of neuroepithelial tumors with varied morphological features. In cIMPACT-NOW update 6, only those with astroblastoma morphology has been accepted as a newly recognized tumor type, whereas the rest of morphological variants are considered lesions sub-judice. We perform an individual patient data meta-analysis of MN1-altered neuroepithelial tumors comprising a total of 73 cases, in order to study the survival data and predictive markers for better diagnosis and management of this rare molecular entity.

View Article and Find Full Text PDF

To determine the frequency of discordance in programmed death-ligand 1(PD-L1) expression between primary tumors and paired distant metastases in advanced cancers. We searched MEDLINE and EMBASE for eligible studies and assessed their methodologic quality using QUADAS-2 tool. We estimated the discordant rates (positive to negative or vice versa) of PD-L1 expression in primary tumors and paired distant metastases using logistic-normal random effects model.

View Article and Find Full Text PDF

Myxopapillary ependymomas are a slow-growing, grade I type glial tumor in the lumbosacral region. More rarely, they can present as extradural, subcutaneous sacrococcygeal, or perisacral masses, and it is under these circumstances that they are more likely to spread. Here, we report the presentation of a sacrococcygeal mass in patient that was initially resected confirming extradural myxopapillary ependymoma.

View Article and Find Full Text PDF

Oligodendrogliomas, the third most common primary gliomas, have a strict molecular definition, characterized by the combined presence of isocitrate dehydrogenase mutation and 1p19q codeletion. Herein, we describe an extremely unusual case of molecularly defined anaplastic oligodendroglioma with transdural extension into the frontal and ethmoid sinuses, without prior neurosurgical intervention or radiotherapy. The molecular profile of the tumor is also provided.

View Article and Find Full Text PDF

Purpose: To evaluate the rate of discordance of epidermal growth factor receptor (EGFR) mutation between primary lung tumor and paired distant metastases in non-small-cell lung cancer (NSCLC).

Methods: We performed a meta-analysis of 17 studies (518 cases) assessing discordance rates of EGFR mutation in primary tumors and paired distant metastases. We performed subgroup analyses based on EGFR mutation status in primary tumor (mutant or wildtype), site of distant metastasis (bone, central nervous system (CNS) or lung/ pleural), methods of testing (direct sequencing or allele-specific testing) and timing of metastasis (synchronous or metachronous).

View Article and Find Full Text PDF

Objectives: The list of tumors involving the pituitary gland has been expanded to include a variety of neuronal and paraneuronal tumors in the 2017 World Health Organization tumor classification of endocrine organs. All the entities included in this category are distinctly rare, with limited case reports in the literature.

Methods: We illustrate two extraordinary sellar tumors with neuronal differentiation: a sellar paraganglioma and a sellar neurocytoma, with thorough literature review and comparison of the clinicopathologic features of these entities.

View Article and Find Full Text PDF

The use of radiotherapy, either in the form of stereotactic radiosurgery (SRS) or whole-brain radiotherapy (WBRT), remains the cornerstone for the treatment of brain metastases (BM). As the survival of patients with BM is being prolonged, due to improved systemic therapy (i.e.

View Article and Find Full Text PDF

Ollier disease (OD) and Maffucci syndrome are rare conditions due to a post-zygotic somatic mutation that results in mosaicism. In addition to enchondromas and hemangiomas, some of these patients also develop other unrelated tumors, such as gliomas, that harbor IDH mutations, suggesting that an IDH mutation is a common genetic event in the tumorigenesis in this group of patients. We illustrate an interesting case of multifocal IDH-mutant astrocytomas in an OD patient with 8 years of follow-up.

View Article and Find Full Text PDF

Diagnosis and classification of poorly differentiated tumors with primitive features of the central nervous system heavily relies on molecular and genetic findings of the tumors. Although RB1 gene mutation underlies the development of retinoblastoma and many other systemic cancers, RB1 gene mutation in a brain tumor is mainly limited to infiltrating gliomas. We describe what we believe to be a hitherto unreported case of sellar/suprasellar embryonal tumor with distinctive Flexner-Wintersteiner rosette formation, and somatic RB1 gene mutation in a 5-month-old infant.

View Article and Find Full Text PDF

Central neurocytoma is a rare neuronal tumor that typically occurs in young adults. Infrequently, these tumors exhibit advanced neuronal maturation and glial differentiation, giving rise to a histologically diverse tumor, in contrast to a typical central neurocytoma. We present a novel case of intraventricular central neurocytoma with prominent gangliogliomatous differentiation that developed atypical features upon recurrence after 10 years of follow up in a 10-year-old boy.

View Article and Find Full Text PDF

A 38-year-old, previously healthy man presented with blood-stained saliva and epistaxis. A 3 mm nasopharyngeal lesion was found. A biopsy was performed and microscopic examination revealed a Kaposi sarcoma.

View Article and Find Full Text PDF

Background: Spinal extradural cyst (SEDC) accounts for <1% of spinal epidural lesions. It is commonly asymptomatic but can give rise to back pain and compressive neurologic symptoms.

Case Description: We report the case of a 51-year-old male who presented with gait difficulties over 5 months associated with occasional urge incontinence.

View Article and Find Full Text PDF

We report a novel case of a World Health Organization grade 3 anaplastic meningioma arising from the olfactory groove in an 83-year-old woman. Molecular and methylation profiling confirm this lesion to be an NF2 subtype, methylation class intermediate type B meningioma. As most meningiomas in this location are indolent SMO subtype lesions, our report suggests that even though rare, aggressive NF2 subtype meningiomas can also occur along the midline anterior skull base.

View Article and Find Full Text PDF

Glioblastoma (GBM) typically occurs as a primary tumour (i.e., primary GBM) and predominantly affects elderly patients.

View Article and Find Full Text PDF