RESUMO
DISCLAIMER: In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE: To describe the implementation of human leukocyte antigen (HLA)-related genotype-guided prescribing in Singapore. SUMMARY: Various HLA alleles have been implicated in drug hypersensitivity syndromes (DHS). These include HLA-B*15:02, which has been associated with carbamazepine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis, HLA-B*58:01, which has been associated with increased risk of severe cutaneous adverse reactions with allopurinol use, and HLA-B*57:01, which has been associated with increased risk of hypersensitivity reactions with abacavir use. Integrating pharmacogenomics into patient care through genotype-guided prescribing potentially optimizes use of these drugs by reducing DHS-related and healthcare costs. We describe the prevalence of HLA-related DHS in Singapore, the cost-effectiveness of genotype-guided prescribing, and local policies and guidelines, as well as the impact of genotype-guided prescribing where available. CONCLUSION: HLA-related genotype-guided prescribing has the potential to reduce the incidence of DHS and decrease healthcare costs, as seen in the success with carbamazepine. However, not all genotype-guided prescribing is cost-effective when implemented across the population, as was evident from local studies for allopurinol and abacavir. The cost-effectiveness of such measures may change over time with new data (eg, allele frequencies, test costs, drug prices, genotyping approach) and should be evaluated periodically and locally. Implementation of preemptive pharmacogenomics panel testing as part of routine clinical care may shift the threshold for cost-effectiveness and brings promise of further optimization of pharmacotherapy through precision medicine.
RESUMO
Ovarian sex cord-stromal tumours (SCSTs) present diagnostic difficulties during frozen section (FS) consultations due to their diverse morphology. This study aimed to evaluate the accuracy of FS evaluation of SCSTs in our institution, as well as to examine the reasons leading to incorrect FS diagnosis. Cases mimicking SCSTs and diagnosed as such during FS were also highlighted. We analysed 121 ovarian SCST cases and their mimics which underwent FS consultations over a 10-year period, to evaluate FS accuracy, reasons for deferrals and discrepancies. FS diagnoses were concordant, deferred and discrepant compared to the final diagnosis in 50 (41.3%), 39 (32.2%) and 32 (26.5%) cases, respectively. Major discrepancies (9/121, 7.4%) were mostly related to the diagnosis of adult granulosa cell tumour (AGCT). A fibromatous AGCT was misinterpreted as fibroma on FS, while a cystic AGCT was called a benign cyst. Conversely, a mesonephric-like adenocarcinoma, a sertoliform endometrioid carcinoma and a thecoma were misinterpreted as AGCT on FS. Another discrepant case was a Krukenberg tumour with prominent fibromatous stroma in which malignant signet ring cells were overlooked and misinterpreted as fibroma. Minor discrepancies were primarily associated with fibroma (21/23, 91.3%), wherein minor but potentially impactful details such as cellular fibroma and mitotically active cellular fibroma were missed due to sampling issues and misinterpretation as leiomyoma. FS evaluation for ovarian SCSTs demonstrated an overall accuracy of 78.5%, 81.0% and 81.8% for benign, uncertain/low malignant potential and malignant categories, respectively. There was no FS-related adverse clinical impact in all cases with available follow-up information (120/121 cases). Intraoperative FS evaluation of ovarian SCSTs is challenging. A small number of cases were misinterpreted, with AGCTs being the primary group where errors occur. Awareness of common diagnostic pitfalls and difficulties, alongside application of a stepwise approach, including (1) obtaining comprehensive clinical information, (2) thorough macroscopic examination and directed sampling, (3) meticulous microscopic examination with consideration of pitfalls and mimics, (4) effective communication with surgeons in difficult cases, and (5) consultation of subspecialty colleagues in challenging cases, will enhance pathologists' reporting accuracy and management of such cases in the future.