Unclassified Cases Research Articles (Page 1)

Background Gender inference from names is widely used in bibliometric and epidemiologic research, including in general internal medicine. Traditional tools such as Gender API and NamSor are considered accurate but remain limited by misclassifications and unclassified cases. Recent studies suggest that ChatGPT may perform comparably to these tools. We aimed to test whether a two-step procedure could further improve ChatGPT’s performance. Methods We evaluated ChatGPT-5 against Gender API using a random sample of 1,000 Swiss physicians. A two-step one-shot prompt was applied: 1-assign gender directly from the name if reliable; 2-otherwise, verify using the internet. Gender API was applied to the same dataset with no threshold and at probability thresholds of ≥60%, ≥70%, ≥80%, and ≥90%. Confusion matrices, McNemar’s test, and accuracy metrics (errorCoded, errorCodedWithoutNA, naCoded) were computed. Results Of 1,000 physicians, 523 (52.3%) were women and 477 (47.7%) were men. ChatGPT-5 achieved 996 correct classifications (99.6%), with 4 errors and no unclassified cases, whereas Gender API (whole sample) achieved 977 correct classifications (97.7%), 18 errors, and 5 unclassified cases (p-value<0.001). At higher thresholds, Gender API reduced errors but produced up to 6.5% unclassified cases. Overall error rates (errorCoded) were 0.4% for ChatGPT-5 versus 2.3% for Gender API. ChatGPT-5 marked 10.1% of names as “checked” through internet verification, increasing to 69.6% among cases that Gender API misclassified or left unclassified. Conclusion ChatGPT-5 substantially outperformed Gender API in gender inference from physicians’ names, achieving near-perfect accuracy without unclassified cases. Its adaptive use of internet verification for difficult names may offer a robust and efficient approach for large-scale research.

High-grade glioma, IDH- and H3-wildtype in young adults is a rare and poorly known entity. We compared newly diagnosed cases in young adults (18-39 years) to those in adult patients (> 39 years). We performed an observational, retrospective, single-centre cohort study at a tertiary neurosurgical oncology centre between January 2006 and December 2023. We included 1.139 adult patients with a newly diagnosed high-grade glioma, IDH- and H3-wildtype. Young adults: (1) represent a small proportion of patients with high-grade glioma (n = 33, 2.9%); (2) have a high rate of unclassified cases based on epigenetics (n = 5, 15.2%); (3) have a longer progression-free survival (p = 0.003) and overall survival (p = 0.001) and; (4) do not have higher surgically-related adverse event rates (p = 0.198). Concerning young adults, surgical resection was associated with improved progression-free and overall survival (p < 0.001 and p < 0.001, respectively). The DNA-methylation class significantly impacts the overall survival (p = 0.028), however, the MGMT methylation status is not significantly associated with either progression-free or overall survival (p = 0.320 and p = 0.639, respectively). High-grade glioma, IDH- and H3-wildtype is a rare histo-molecular subtype in young adults with a better prognosis than older adults. In young adults, DNA-methylation subtypes are different from their adult counterpart and had a significant impact on survival unlike MGMT status. Given the rarity in young adults, a dedicated management in specialized neurosurgical oncology centres is preferred. Further molecular and epigenetic analyses are required to understand the differences in prognosis compared to adult patients.

Terminal deoxynucleotidyl transferase (TdT) is occasionally expressed in large B-cell lymphoma (LBCL), and this causes difficulty in differential diagnosis from B-lymphoblastic leukaemia/lymphoma (B-ALL/LBL). We reviewed 31 cases of TdT-positive LBCL and B-ALL/LBL, and their final diagnosis included 19 diffuse large/high-grade BCLs with MYC and BCL2 rearrangements (five DLBCL-MYC/BCL2, 14 HGBCL-MYC/BCL2), three DLBCL not otherwise specified (NOS), three HGBCL-NOS, four B-ALL/LBL, and two unclassifiable cases. TdT was variably expressed in all these cases, without any clear demarcation among different groups. Loss or partial loss of CD20 expression was seen in 13/17 DLBCL/HGBCL-MYC/BCL2, 2/3 HGBCL-NOS, and 2/2 unclassified, albeit not in DLBCL-NOS. Expression of BCL6 and/or MUM1 was seen in 3/4 B-ALL/LBLs and 2/2 unclassified. Next-generation sequencing revealed characteristic mutations associated with follicular lymphoma and its high-grade transformation in each DLBCL/HGBCL-MYC/BCL2, and also frequent variants in genes targeted by somatic hypermutation (SHM) in almost all DLBCL/HGBCL-MYC/BCL2, DLBCL-NOS, and HGBCL-NOS but one case. In contrast, such mutations were absent in B-ALL/LBL. There were no pathognomonic mutations in the two unclassifiable cases, although one showed a moderate level of somatic mutations in its rearranged IGHV. Furthermore, in three cases of TdT-positive HGBCL-MYC/BCL2, studies of previous or concurrent follicular lymphoma demonstrated their divergent evolution from an IGH::BCL2-positive cell population following acquisition of MYC translocation. In conclusion, mutation profiling analysis including the SHM target genes is highly valuable in the differential diagnosis between TdT-positive LBCL and B-ALL/LBL. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Rare diseases, defined by the 2002 Rare Disease Act, affect fewer than 5 in 10,000 individuals. Rare metabolic bone diseases (MBDs), such as osteogenesis imperfecta, hypophosphatasia, osteopetrosis, and other unclassified disorders, can disrupt bone development and remodeling, posing diagnostic and management challenges. This study analyzed data from the rarembd.in registry (2010-2024), a 15-year database documenting only rare MBDs. Clinical presentation and demographic data of patients with rare MBDs were collated. Common MBDs (osteoporosis, primary hyperparathyroidism) were excluded. Genetic testing was performed in a subset of patients. There was a total of 218 patients with an almost equal gender distribution (male-to-female ratio of 1:1.07) and a mean age of 29.1 ± 18.9years. The registry identified 29 rare MBDs with three main disease categories: demineralization disorders (50.4%), disorders of bone matrix and cartilage formation (32.5%), and sclerotic disorders (13.7%); with a smaller proportion categorized as unclassified bone disorders (2.7%). Rickets/osteomalacia (27.1%) was the most common, followed by osteogenesis imperfecta (23.4%) and fibrous dysplasia/McCune-Albright syndrome (18.8%). Fractures affected 57.7% of patients, with 24.5% experiencing multiple fractures, while 31.1% exhibited skeletal deformities. Mutation analysis in our registry identified pathogenic variants in the SOST, TGFβ1, SLC34A3, ALPL, and VCP genes, confirming the genetic basis of sclerosteosis, Camurati-Engelmann disease, hypophosphatemic rickets, hypophosphatasia, and IBMPFD, respectively. Different management strategies were used that included teriparatide, bisphosphonates (zoledronate or alendronate) with total contact casting, intralesional zoledronate, denosumab, calcium, active vitamin D, and recombinant human growth hormone. Total parathyroidectomy was performed in specific cases. The registry classified RMBDs into four categories, with demineralization disorders being the most common, followed by bone matrix/cartilage formation disorders, sclerotic diseases, and unclassified cases. There were 29 RMBDs, and rickets/osteomalacia was the most prevalent subtype, tumor-induced osteomalacia followed by familial hypophosphatemic osteomalacia. Among the unclassified bone disorders, fragility fractures emerged as the most common presentation.

Beyond cloacal malformation. Addressing unclassifiable complexity.

Background/Objectives: Pediatric episodic vestibular syndrome (EVS) is increasingly recognized, with recurrent vertigo of childhood (RVC) and vestibular migraine of childhood (VMC) being the most prevalent disorders. In 2021, the Bárány Society and the International Headache Society proposed new diagnostic criteria for RVC, VMC, and probable VMC (pVMC), replacing the older term benign paroxysmal vertigo (BPV). This study aimed to evaluate the clinical applicability of these new criteria. Methods: We conducted a cross-sectional study at a pediatric neurotology clinic within a tertiary hospital, including patients under 18 years with episodic vestibular symptoms evaluated between 2018 and 2025. All patients underwent a standardized neuro-otological assessment. Diagnoses were assigned using both the 2018 ICHD-3 and the 2021 Bárány criteria. Patients who did not fulfill any of the three new diagnostic categories, nor met criteria for any other specific vestibular disorder, were grouped into an undetermined category referred to as episodic vestibular syndrome without hearing loss (EVSw/oHL). Demographic and clinical variables were compared across diagnostic groups using non-parametric and chi-squared tests. Results: Among the 202 children evaluated, 109 met the inclusion criteria and were classified as RVC (n = 55), VMC (n = 23), pVMC (n = 13), or EVSw/oHL (n = 18). All patients previously diagnosed with BPV met the new criteria for RVC. Application of the Bárány criteria significantly reduced the proportion of unclassified EVS cases (from 35.78% to 16.51%). Significant clinical differences were observed among the groups in terms of episode duration, presence of vomiting, migraine and headache, and family history of migraine. Conclusions: The new Bárány criteria provide a more inclusive and clinically meaningful framework for classifying pediatric EVS. They improve diagnostic clarity, reduce the proportion of unclassifiable cases, and support earlier and more tailored management strategies.

Introduction and Objective: Type 2 diabetes (T2D) may be associated with higher cancer risk through chronic inflammation, insulin resistance, and obesity. We assessed cancer risks across T2D subtypes. Methods: Newly diagnosed T2D (n = 727,076; age: 64.4 years [SD:13.3], 52% female) over 2012-2023 from the Epic Cosmos platform were classified into Severe Insulin-Deficient Diabetes (SIDD, 21.6%), Mild Obesity-Related Diabetes (MOD, 23.8%), or Mild Age-Related Diabetes (MARD, 40.9%) using reliable algorithms. Unclassified cases were labeled as Mixed (13.7%). First occurrence of cancers (colorectal, liver, pancreatic, female [breast, endometrial, and ovarian], prostate) within ten years after T2D diagnosis were identified using ICD-10-CM codes. Cox proportional hazards models were used to estimate absolute and relative hazards (HR) by subtype, adjusted for age, sex, and smoking. Results: Cumulative cancers were highest in MOD and Mixed. Patterns for specific cancer risks differed: compared to MOD (Figure), SIDD and MARD had 35-111% higher hazards of liver, pancreatic, and prostate cancers but 10-36% lower hazards of colorectal and female cancers. Conclusion: Novel subtypes exhibit varying risks for different cancers, highlighting opportunities for early screening and tailored prevention strategies. Disclosure Z. Li: None. B. Salazar: None. J. Guo: None. K.O. Sanaka: None. P. Vellanki: Advisory Panel; Eli Lilly and Company. M.K. Ali: Advisory Panel; Eli Lilly and Company. C. Hofmeister: Research Support; AbbVie Inc, Sanofi, Bristol-Myers Squibb Company. J. Varghese: None.

Introduction: Rhabdomyosarcoma (RMS) is a prevalent paediatric soft-tissue sarcoma. Among the four histomorphological subtypes of RMS, distinguishing the dense pattern of Embryonal RMS (ERMS) from the solid pattern of Alveolar RMS (ARMS) solely based on morphology is challenging and necessitates ancillary techniques. Aim: To study the demographics, classify the histomorphological subtypes and reclassify the morphologically overlapping embryonal and ARMS cases into specific subtypes based on the intensity of myogenin expression and the FOXO1 gene fusion status. Materials and Methods: This cohort study was conducted at the Kidwai Memorial Institute of Oncology, Bengaluru, Karnataka, India, from January 2019 to December 2022. The study included 71 cases of RMS. Clinical data such as age, gender, tumour site, size and clinical stage, along with histomorphological types, were analysed. A panel of immunomarkers was performed based on morphological differentials, which included desmin, myogenin, MyoD1, CD99, synaptophysin, chromogranin, PanCK, NKX2.2, INI1, CD56, S100, CD34 and SMA. Myogenin expression was scored based on the extent of tumour cell positivity. Interphase Fluorescence In Situ Hybridization (FISH) analysis was conducted on all ARMS and morphologically unclassified cases using the CytoTest Break Apart Probe for the FOXO1 gene. One hundred tumour cells were analysed and split signals, with or without amplification signals in at least 15 cells, were considered positive. Results: A male preponderance was noted (43/71, 60.6%), with a higher incidence among children under 14 years (42/71, 59.2%). ERMS was the most common histological subtype (26/71, 36.6%), followed by ARMS (13/71, 18.3%) and Spindle Cell RMS (SCRMS) (7 cases, 9.9%). The head and neck regions were frequently involved (24 cases, 33%). Twenty-three cases of unclassified RMS were reclassified into ARMS (fusion-positive) (43.4%, n=10) and reclassified ERMS (fusion-negative) (34.7%, n=8). Notably, the correlation between myogenin expression and FOXO1 fusion showed that 94.7% of fusion-positive cases exhibited 4+ myogenin expression (p-value &lt;0.001). Overall, ARMS had the worst overall survival (OS) rate (26.1%). The reclassified ERMS and the classic ERMS cases showed almost similar survival rates (62.5% vs 64.2%, respectively) (p-value=0.025). Conclusion: The study highlights that the myogenin immunomarker is useful in differentiating between ERMS and ARMS in resource-constrained settings and emphasises the need for fusion testing in ARMS and unclassified RMS cases for accurate risk assessment and tailored treatment strategies.

ABSTRACT Background: Hodgkin’s lymphoma is a malignant tumor of the lymph nodes that causes painless lymphadenopathy. Diagnosing it can be challenging, especially in the early stages, due to often nonspecific symptoms. This study addresses our center’s increased Hodgkin’s lymphoma (HL) incidence. Given the limited literature on this subject, we aim to enhance our understanding of HL’s incidence and clinicopathological features in our environment. Methods: This retrospective study analyzed HL cases from 2010 to 2022 at Lagos University Teaching Hospital and two private laboratories. Clinical data were gathered from case files and laboratory requests, and both hematoxylin-eosin-stained sections and immunohistochemical slides were reviewed to classify the diseases morphologically. Results: A total of 50 HL cases were identified, primarily in the cervical region, with 5 and 4 cases in the inguinal and axillary regions, respectively. Among the 34 with clinical information, there were 35% in Ann Arbor stage I, 15% in stage II, none in stage III, and 9% in stage IV, while 41% had unspecified stages. The cohort comprised 40 males and 10 females, with a male-to-female ratio of 4:1. Ages ranged from 2 to 72 (mean 32.8), and most cases (68%) involved individuals in their third to fifth decades. Histologically, the breakdown was 44% nodular sclerosis, 30% mixed cellularity, 8% lymphocyte-rich, 4% lymphocyte-depleted, and four unclassified cases. Conclusions: HL is common at our center. It typically presents at a late stage, predominantly nodal, and is more frequent in young adult males. The nodular sclerosis (NS) subtype is the most common, and a bimodal peak is not observed. The increased frequency among young people and late presentations indicates a need for improved access to clinical and diagnostic services.

Diffuse Large B-Cell Lymphoma (DLBCL) is a heterogeneous disease characterized by a limited number of molecularly defined subtypes. Recently, genomic-based algorithms have been proposed for the classification of this disease. The whole exome sequencing was conducted on 108 diagnostic samples of diffuse large B-cell lymphoma (DLBCL). Somatic variants, predicted copy number alterations (CNAs), and available fusion data were utilized to classify the cases. Additionally, the enrichment of mutations in the TP53, MYC, and MAPK/ERK pathways was analyzed. Genetic subtypes were identified in approximately 55% of the cases. Cases with a specific genetic subtype exhibited a significantly higher Tumor Mutation Burden compared to molecularly unclassified cases (Mann-Whitney U test, p = 0.024). The prevalence of subtypes varied according to the cell of origin phenotypes. GC-B type DLBCL NOS were classified as EZB (5 cases, 16%), ST2 (5 cases, 16%), and BN2 (1 case, 3%). Four cases (13%) were genetically composite. Three cases of HGBCL/DLBCL double-hit (MYC & BCL2) were classified as EZB-MYC. Forty-three non-GC-B type DLBCL cases were classified as ST2 (5 cases, 11%), BN2 (6 cases, 14%), and MCD (3 cases, 7%). Nine cases were genetically composite (20%). MYC pathway mutations were enriched in cases with EZB and ST2 genetic features, while they were absent in the MCD subtype. TP53 mutations were identified in 11% of the cases. Plasmablastic lymphomas exhibit genetic diversity, with 27% of tumors classified as ST2. Recurrent somatic mutations indicate dysregulation of the JAK/STAT, MAPK/ERK, and tyrosine kinase signaling pathways.

Background/Objectives: Renal cell carcinoma is an aggressive form of kidney cancer, contributing to an estimated 138,000 deaths globally in 2017. Traditional treatments like chemotherapy and radiation are generally considered ineffective. Additionally, CD47 has been identified as a crucial tumor antigen involved in the development and progression of various cancers, including renal cell carcinoma. The interaction of CD47 with SIRPα triggers a "don't eat me" signal to the macrophages, inhibiting phagocytosis. Much progress has been made in targeting CD47 for cancer immunotherapy in solid tumors (STs) and hematological malignancies. This study aimed to evaluate CD47 expression in malignant and benign renal cell tumors and compare it with prognostic histopathological parameters. Methods: We included 160 malignant and 26 benign tumors. The malignant tumors consisted of renal cell carcinoma (RCC) subtypes including 37 clear cell, 30 chromophobe, 30 papillary type 1, 29 papillary type 2, and 34 unclassified RCC cases. As for the benign tumors, we included 26 oncocytoma cases. All samples were stained with anti-CD47 antibodies by immunohistochemistry methods. Results: The statistical analysis yielded a significant correlation between CD47 expression and survival, metastasis, and capsule invasion for the unclassified RCC cases. We did not find any further significant correlation between CD47 expression and the studied parameters. Conclusions: To the best of our knowledge, our study is the first to research CD47 expression in benign and malignant renal carcinoma subtypes. Further large-scale studies are needed to determine the expression profile of CD47 in renal cell tumors.

This epidemiological study aimed to identify the primary categories of kidney pathology diagnosis and their prevalence among patients admitted to Shahid Labbafinezhad Teaching Hospital. We included 1006 kidney biopsy findings from 2019 to 2022. The majority of kidney patients (78%) were between the ages of 20 and 60 years. Nephrotic syndrome made up 62% of the patient population. The findings revealed that primary glomerulonephritis, secondary glomerulonephritis, tubular/interstitial nephritis, end-stage kidney disease, and unclassified cases accounted for 63%, 17%, 12%, 6%, and 2% of kidney disease cases, respectively. The inclusion of a large number of patients from various regions across the country, combined with the expertise of the laboratory staff, underscores the reliability and significance of the results obtained in this study.

The classification of TFEB-altered renal cell carcinoma (RCC) has been revised to include TFEB-rearranged RCC and TFEB-amplified RCC in the 2022 World Health Organization (WHO) Classification of Tumors of the Urinary System. Given the wide spectrum of TFEB-altered RCC in terms of morphology and clinical behavior, an accurate diagnosis is challenging yet crucial, particularly in aggressive cases. Moreover, the concurrence of TFEB gene rearrangement and amplification/gene copy number (GCN) gains was also observed, but there was limited knowledge of these cases. We presented three TFEB-rearranged RCC cases, one TFEB-amplified RCC case, and one case of concomitant TFEB-rearranged and -amplified RCC, comparing the similarities and differences among these three subgroups. Furthermore, we summarized the clinicopathological and molecular features of TFEB-rearranged RCC concomitant with TFEB amplification/GCN gains from the literature and the present study. TFEB-altered RCCs exhibit significant heterogeneity in morphology and clinical behavior while displaying similar immunohistochemical profiles, including positive staining for Melan-A, PAX8, and CD117, and negative staining for CK7. A typical biphasic "rosette-like" morphology has been observed in a proportion of TFEB-rearranged RCC concomitant with TFEB amplification/GCN gains, which has been noted in TFEB-rearranged RCC, but not in cases with only TFEB amplification. Notably, TFEB-rearranged RCCs concomitant with TFEB amplification/GCN gains tend to be aggressive, in contrast to the often indolent nature of TFEB-rearranged cases, irrespective of the extent of TFEB gene copy increase. Therefore, a TFEB FISH assay is essential for unclassified RCC cases that exhibit melanocytic marker expression, and fluorescent signals should be counted and interpreted acurrately.

<i>SF3B1</i> Mutation Significance in Myeloid Neoplasms without Anemia

Fibrosing interstitial lung diseases (ILDs) encompass a diverse range of scarring disorders that lead to progressive lung failure. Previous gene expression profiling studies focused on idiopathic pulmonary fibrosis (IPF) and bulk tissue samples. We employed digital spatial profiling to gain new insights into the spatial resolution of gene expression across distinct lung microenvironments (LMEs) in IPF, chronic hypersensitivity pneumonitis (CHP) and non-specific interstitial pneumonia (NSIP). We identified differentially expressed genes between LMEs within each condition, and across histologically similar regions between conditions. Uninvolved regions in IPF and CHP were distinct from normal controls, and displayed potential therapeutic targets. Hallmark LMEs of each condition retained distinct gene signatures, but these could not be reproduced in matched lung tissue samples. Based on these profiles and unsupervised clustering, we grouped previously unclassified ILD cases into NSIP or CHP. Overall, our work uniquely dissects gene expression profiles between LMEs within and across different types of fibrosing ILDs.

To compare maternal demographics based on occupation coding status and evaluate potential bias by excluding manually coded occupations. This case-control study assessed cases with clefts obtained from the Texas Birth Defects Registry. The NIOSH Industry and Occupation Computerized Coding System automatically coded occupations, with manual coding for unclassified cases. Maternal demographics were tabulated by occupation coding status (manual vs. automatic). Logistic regression examined associations between major occupation groups and clefts. Automatic coding covered over 90% of all mothers. Building, grounds cleaning, and maintenance occupations, and office and administrative support occupations were significantly associated with cleft lip with or without cleft palate, even after excluding manually coded occupations. We found consistent associations before and after excluding manually coded data for most comparisons, suggesting that machine learning can facilitate occupation-related birth defects research.

Artificial intelligence’s main component, machine learning, enables systems to learn on their own and improve performance via experience, doing away with the need for explicit programming. This cutting-edge field focuses on equipping computer programs with the ability to access vast datasets and derive intelligent decisions from them. One of the cornerstone algorithms in machine learning, the K-nearest neighbours (KNN) algorithm, is known for its simplicity and effectiveness. KNN leverages the principle of storing all available data points within its training dataset and subsequently classifying new, unclassified cases based on their similarity to the existing dataset. This proximity-based classification approach renders KNN a versatile and intuitive tool with applications spanning diverse domains. This document explores the inner workings of the K-nearest neighbours’ algorithm, its practical applications across various domains, and a comprehensive examination of its strengths and limitations. Additionally, it offers insights into practical considerations and best practices for the effective implementation of KNN, illuminating its significance in the continually evolving landscape of machine learning and artificial intelligence.

DNA methylation analysis has become a powerful tool in neuropathology. Although DNA methylation-based classification usually shows high accuracy, certain samples cannot be classified and remain clinically challenging. We aimed to gain insight into these cases from a clinical perspective. To address, central nervous system (CNS) tumors were subjected to DNA methylation profiling and classified according to their calibrated score using the DKFZ brain tumor classifier (V11.4) as "≥ 0.84" (score ≥ 0.84), "0.3-0.84" (score 0.3-0.84), or "< 0.3" (score < 0.3). Histopathology, patient characteristics, DNA input amount, and tumor purity were correlated. Clinical outcome parameters were time to treatment decision, progression-free, and overall survival. In 1481 patients, the classifier identified 69 (4.6%) tumors with an unreliable score as "< 0.3". Younger age (P < 0.01) and lower tumor purity (P < 0.01) compromised accurate classification. A clinical impact was demonstrated as unclassifiable cases ("< 0.3") had a longer time to treatment decision (P < 0.0001). In a subset of glioblastomas, these cases experienced an increased time to adjuvant treatment start (P < 0.001) and unfavorable survival (P < 0.025). Although DNA methylation profiling adds an important contribution to CNS tumor diagnostics, clinicians should be aware of a potentially longer time to treatment initiation, especially in malignant brain tumors.

We aimed to evaluate the clinical significance of the "unclassified" blood pressure phenotypes on left ventricular hypertrophy in children. All children evaluated with ambulatory blood pressure monitoring in the pediatric nephrology department between October 2018 and January 2021 were included in the study. Prehypertension, normotensive, white coat hypertension, masked hypertension, ambulatory hypertension groups and 2 other groups including increased blood pressure load, normal ambulatory blood pressure measurements, but normal (unclassified group 1) or high (unclassified group 2) office blood pressure measurements were defined according to the American Heart Association 2014 statement. Left ventricular mass index, left ventricular mass index/95 percentile values, and left ventricular hypertrophy ratios were compared between the groups separately to establish the influence of the unclassified cases. A total of 497 children were included. There were 52 cases in normotensive, 47 cases in unclassified group 1, 50 cases in masked hypertension, 79 cases in white coat hypertension, 104 cases in unclassified group 2, and 165 cases in the ambulatory hypertension group. Left ventricular mass index/95 percentile and left ventricular hypertrophy in masked hypertension were significantly higher than normotensive but similar between normotensive and unclassified group 1 groups. Left ventricular hypertrophy was significantly higher in the ambulatory hypertension group compared to white coat hypertension, and similar between white coat hypertension and unclassified group 2 groups. Independent of age, we have found that interpretation of blood pressure load not only has a limited predictable effect on left ventricular hypertrophy but also causes a large group of patients to be unclassified. Cite this article as: Kasap-Demir B, Başaran C, Demircan T, et al. The effect of "unclassified" blood pressure phenotypes on left ventricular hypertrophy. Turk Arch Pediatr. 2024;59(1):43-48.

Canine mast cell tumors (MCT) in the skin are classified into cutaneous MCT (cMCT) and subcutaneous MCT (scMCT) types, which exhibit different clinical behaviors. Although these types have been classified only by histology, preoperative differentiation is important for proper surgical planning. To examine the accuracy of differentiating these types based on the gross features before surgery. Gross photographic and histologic features of 52 MCTs (2014-2022) were retrospectively compared between cMCTs and scMCTs. Based on these results, we grossly classified an additional 25 MCTs (2007-2013) into two forms using photographic observations. These observations were then compared with the results of histological classification performed by a blinded pathologist. The most notable difference between the two forms was hair loss on the tumor surface. Hair loss was prominent in all 36 cMCTs but minimal or absent in all 16 scMCTs. Histologically, only the cMCT showed prominent follicular reduction due to MCT infiltration. Using the hair loss feature, we classified an additional 25 MCTs: 15 cMCTs, 7 scMCTs, and 3 unclassifiable cases with overlapping features. Agreement with histological classification was 80% (12/15) for cMCT and 100% (7/7) for scMCT. Among the unclassifiable cases, one was cMCT, and two were scMCT. Large tumors (3.5-10.5 cm) were found in two of the three unclassifiable cases and in all three cases without agreement. Hair loss on the tumor surface is a distinct feature of cMCT that enables accurate visual differentiation from scMCT, except for some large MCTs. This may assist in surgical planning, specifically for sc-MCT.