Common Lesions Research Articles

Umbilical keratinous cyst in a 7-year-old girl: A case report

Keratinous cysts, the most common kind of epidermal cysts, are filled with keratin originating from the epidermis, most often from the hair follicle. Keratinous cyst is one of the most common skin lesions and occurs most commonly in the face, head, trunk, extremities, and genitals. A 7-year-old girl reported to the pediatric surgery department with a painless, small tumor arising from her umbilicus. There was no history of trauma, and it has been slowly growing for the past many years. Clinical examination revealed a 3-cm-long skin tag with three small interconnected tumors from the umbilicus. It was soft, and the parts of the tumors looked like they contained whitish material inside. Her general and other systems, including the abdominal examinations, were within the normal limits. The tumor was resected through a sub-umbilical skin incision. She made an uninterrupted recovery. The excised specimens subjected to histology were reported as superficial keratinous cysts. Keratinous cysts are one of the most common benign skin lesions, but not the most common, at the umbilicus. Clinicians need to be aware of such pathology during the evaluation of the umbilical swellings and tumors, especially in children.

A Novel Case of Paediatric Petrous Apex Cholesterol Granuloma.

The petrous apex is medial most part of temporal bone, which is surrounded by vital structures. Cholesterol granuloma is the most common benign lesion of the petrous apex. Symptoms are related to mass effect and/or direct involvement of closely adjacent vital structures. The lesions can be manged either by open surgery via craniotomy or through the newer endoscopic approach. Case report and review of the literature concerning cholesterol granulomas of the petrous apex and their management. The lesion was approached endoscopically trans nasal and trans sphenoid and cholesterol granuloma was excised and marsupialised. Post operative patient recovery was uneventful. Endonasal Endoscopic approach has significantly lower complication rate when compared to open approaches. Petrous apex lesions are rare and need a multidisciplinary team approach for optimal management. By endoscopic approach one can remove lesion or marsupialize the sac with natural drainage into sinus and result in better prognosis and minimal chance of recurrence. Endonasal procedure has also lower complication rates and shorter median follow-up than open approaches.

A systematic review of blunt abdominal aortic injury and analysis of predictors of death.

At present, research on blunt abdominal aortic injury (BAAI) is limited, with the majority being case reports. Consequently, there is a significant knowledge gap concerning this condition. To address this, we conducted a systematic review by extensively searching major databases. We included all literature that provided individual (non-identifiable) data on BAAI patients, irrespective of the study design. Furthermore, we undertook regression analyses to identify predictors of death after BAAI. The search yielded 2,099 results, leading to the inclusion of 102 case reports and one conference abstract. Using the Joanna Briggs Institute (JBI) checklist for assessment, all studies were deemed of medium to high quality. In total, 133 patients were included, with a median age of 34 years, and 73.7% being male. The predominant clinical manifestation was pain, reported in 65.6% of patients. The most frequently observed aortic lesion severity was grade A (intimal tear or intramural hematoma) at 46.9%, and the most common lesion location was zone III (infrarenal aorta) in 88.3% of cases. The overall mortality after BAAI was 15.3%. Multivariate regression analyses revealed the following predictors of death after BAAI: lower limb ischemia (relative risk [RR] = 7.137, 95% confidence interval [CI] 1.154 - 44.161), cardiopulmonary arrest (RR = 10.250, 95% CI 1.452 - 72.344), and injuries to body parts other than the abdomen and lumbar spine (RR = 2.593, 95% CI 1.189 - 5.655). In conclusion, this review provides a detailed quantitative summary of BAAI's clinical manifestations, diagnosis, treatment, and prognosis, emphasizing its high mortality rate and identifying three critical variables as predictors of death.

A Hospital-Based Cross-Sectional Study on the Histopathology of Upper Gastrointestinal Tract Endoscopic Biopsy in Dyspeptic Patients.

Background Dyspepsia is one of the most common GI complaints encountered in clinical practice. Histopathological assessment of endoscopic gastric mucosa biopsy is crucial to delineate the exact cause of dyspepsia to guide patients' management. Objectives The aim of this study was to determine the histopathological spectrum of upper gastrointestinal (GI) tract endoscopic biopsies and to study the age and sex distribution of the predominant upper GI lesions. Methods A cross-sectional study was conducted in the Department of Pathology, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India, from January 2022 to December 2023. All endoscopic mucosal biopsies of the esophagus, stomach, and duodenum (first and second parts) lesions were examined under a microscope for histopathological findings. Results Out of 250 endoscopic biopsies studied, there were 76 cases of esophageal biopsies, 149 cases of gastric biopsies, and 25 cases of duodenal biopsies. The male-to-female ratio was 1.2:1. Non-neoplastic lesions were more common than neoplastic lesions. The most common lesions encountered were esophagitis in the esophagus, gastritis in the stomach, and duodenitis in the duodenum. Conclusion The main organic cause of dyspepsia in our setting was chronic gastritis. We conclude that endoscopy of the upper GI tract and histopathological examination help in the earlier detection of both benign and malignant lesions. This aids in better timely management of the patients and improves the overall treatment provided resulting in a better prognosis.

Nasopharyngeal tumors with unusual presentations: a retrospective analysis from Saudi Arabia

The most common malignant lesion in the nasopharynx is the nasopharyngeal carcinoma (NPC), commonly presents with painless upper cervical lymphadenopathy secondary to nodal metastasis and the undifferentiated type is the most common diagnosis. Compared with other types of cancers, NPC is uncommon, albeit with a high difference in geographical distribution where the worldwide cases account for only 0.6% of all annually diagnosed cancers diagnosed, however, in Saudi Arabia the overall incidence among all age groups is 0.1–0.13 per 10 000. Other rare types of malignancies are also seen at the nasopharynx and due to the nonspecific clinical and imaging characteristics; the preoperative diagnosis may be difficult. This study retrospectively assessed the nasopharyngeal tumors diagnosed in a referral hospital in Al-Baha regions, Saudi Arabia during 10 years period that came with unusual presentations at the level of clinical, radiological, or pathological features to raise the awareness of healthcare provides by these entities. Twenty patients were included and revealed unusual (atypical) clinical presentation in 50% of case including a case presented with respiratory symptoms as a first presentation where multiple lung foci were seen and proved to be a metastatic NPC. Histopathological diagnoses were challenging for 40% of the cases revealing unusual malignant types. In summary, however, the nasopharyngeal malignancy is a rare entity, accurate diagnosis may be missed in clinical or even in the pathology examination. Surgeons and pathologists should be aware of the unusual presentation to provide early and more accurate diagnosis for such serous tumors.

Histological Outcome of Conjunctival Lesions at a Tertiary Hospital in North East Nigeria

Objective: The objective of this study was to determine the relative frequency of histologically diagnosed conjunctival lesions at a tertiary hospital over a 12-month period. Methods: It was a prospective study in which all patients who presented to the ophthalmology clinic with suspicious conjunctival lesions between January and December 2022 were recruited. Data recorded were age, sex, duration of the growth and the affected eye. All the patients underwent basic ocular examination and an examination of the growth to document its site and size. Lesions were excised in the operating theatre under anaesthesia. The excised tissue was preserved in a formalin bottle and sent for histology. Data were entered into Excel and analysed using SPSS version 20.0. Results: A total of 73 eyes were recruited during the period of study. There were 41 males (56.2%) with M:F ratio of 1.3:1. Mean age was 38.44 ± 19.07 years with a range of 2–77 years. Forty patients (54.8%) presented with lesions in the right eye and 33 (45.2%) in the left eye. Fifteen types of conjunctival lesions were diagnosed, including pterygium 37%, conjunctival intraepithelial neoplasia 2.7%, melanoma 2.7%, ocular surface squamous neoplasia 4.1% and squamous cell carcinoma 4.1%, respectively. Conclusion: Pterygium was the most common benign lesion in this study. When conjunctival lesions appear suspicious, it is of utmost importance for the surgeons to differentiate between benign, premalignant and malignant lesions as this may aid in prompt patient management as well as better outcomes.

Radiological features of screening-detected and interval breast cancers and subsequent survival in Eastern Finnish women.

Interval breast cancers are diagnosed between scheduled screenings and differ in many respects from screening-detected cancers. Studies comparing the survival of patients with interval and screening-detected cancers have reported differing results. The aim of this study was to investigate the radiological and histopathological features and growth rates of screening-detected and interval breast cancers and subsequent survival. This retrospective study included 942 female patients aged 50-69years with breast cancers treated and followed-up at Kuopio University Hospital between January 2010 and December 2016. The screening-detected and interval cancers were classified as true, minimal-signs, missed, or occult. The radiological features were assessed on mammograms by one of two specialist breast radiologists with over 15years of experience. A χ2 test was used to examine the association between radiological and pathological variables; an unpaired t test was used to compare the growth rates of missed and minimal-signs cancers; and the Kaplan-Meier estimator was used to examine survival after screening-detected and interval cancers. Sixty occult cancers were excluded, so a total of 882 women (mean age 60.4 ± 5.5years) were included, in whom 581 had screening-detected cancers and 301 interval cancers. Disease-specific survival, overall survival and disease-free survival were all worse after interval cancer than after screening-detected cancer (p < 0.001), with a mean follow-up period of 8.2years. There were no statistically significant differences in survival between the subgroups of screening-detected or interval cancers. Missed interval cancers had faster growth rates (0.47% ± 0.77%/day) than missed screening-detected cancers (0.21% ± 0.11%/day). Most cancers (77.2%) occurred in low-density breasts (< 25%). The most common lesion types were masses (73.9%) and calcifications (13.4%), whereas distortions (1.8%) and asymmetries (1.7%) were the least common. Survival was worse after interval cancers than after screening-detected cancers, attributed to their more-aggressive histopathological characteristics, more nodal and distant metastases, and faster growth rates.

Metastatic Papillary Thyroid Microcarcinoma Presenting as a Branchial Cleft Cyst in Young Female.

Though aetiology of lateral neck masses is complex, branchial cleft cyst is the second most common congenital lesions of the neck next only to thyroglossal duct cysts. Rarely ectopic thyroid tissue within a branchial cleft cyst may develop into primary papillary carcinoma, and even more rarely it may harbour metastases of primary thyroid papillary carcinoma. We report a rare case of lateral cystic neck mass in a 24-year-old female patient diagnosed as metastatic PTC. The patient was diagnosed after she underwent surgical excision of branchial cleft cyst. Later prospectively the patient underwent total thyroidectomy which revealed papillary thyroid micro invasive carcinoma.

Hepatocellular Carcinoma Mimicking Focal Nodular Hyperplasia

Focal nodular hyperplasia (FNH) is a common benign liver lesion, mostly solitary, and with no evidence of malignant transformation over time. The diagnosis can usually be made by imaging modalities with distinct features in magnetic resonance imaging (MRI) and computed tomography (CT) scans. We present a case series of three patients with solitary liver tumors which were, based on radiological features, first diagnosed to be large FNH. The patients were sent to our center for second opinion and probable treatment. Indication for resection was given because of nonconclusive radiologic imaging in the first, substantial growth progression in the second and elevated alpha fetoprotein (AFP) in the third case. Histology revealed well to poor differentiated hepatocellular carcinoma (HCC). FNH tends to show a distinct pattern in imaging modalities, but HCC can mimic FNH. The MRI-scan using hepatotropic contrast agent is the most sensitive imaging modality to diagnose FNH. AFP is usually not elevated in FNH. Asymptomatic FNH does not require surgery but a reliable diagnosis is crucial. In case of an un-certain diagnosis surgery should be offered to patients. In cases with a progression in size, an elevated level of AFP should be suspicious. Generally, an over-therapy via surgery should be avoided and follow-ups of a newly diagnosed FNH including measurement of AFP are advisable to detect alterations.

HIV/AIDS infection: endoscopic characteristics of the most common esophageal lesions and propaedeutics

HIV/AIDS infection: endoscopic characteristics of the most common esophageal lesions and propaedeutics

Pathologic outcome of incidentally detected tracer-avid lesions in 68Ga-PSMA-11 PET/CT for prostate cancer

Abstract Background Prostate-specific membrane antigen (PSMA) PET is effective in identifying prostate cancer metastases. However, PSMA PET uptake has also been described in other lesions, including nonprostate malignancies and benign processes. Purpose To identify causes of unexpected radiopharmaceutical accumulation on PSMA PET. Materials and Methods A total of 2,054 study reports representing 1,873 unique patients who had undergone 68Ga-PSMA-11 PET/CT scans at a single large academic center from December 2015 to April 2022 were retrospectively reviewed for the mention of unexpected PSMA uptake not initially thought to represent metastatic prostate cancer. Scans with pathologic outcome were reviewed by 2 blinded readers for scan indication and lesion location and quantitative parameters. Results In 48 patients, the PSMA ligand–avid incidental lesions revealed 19 cases of second malignancies, 17 cases of prostate cancer, and 13 cases of benign lesions. The most common lesion locations were lung (14), thyroid (14), lymph nodes (8), and bowel (4). Benign lesions exhibited lower molecular imaging PSMA scores (median: 1; interquartile range [IQR]: 1.00-1.25; P = .017) than metastatic prostate lesions (median: 2; IQR: 1-3). Second malignancies were larger (median: 34 mm; IQR: 27-39 mm) than metastatic prostate cancer (median: 14 mm; IQR: 12-19 mm; P = .001) and benign lesions (median: 19 mm; IQR: 13.00-31.00 mm; P = .03). PSMA ligand–avid lesions in scans performed in the initial staging for prostate cancer were more commonly associated with a diagnosis of a secondary malignancy than with metastatic prostate cancer (0 vs 8 lesions, P = .008). Higher standardized uptake value maximum was observed for metastatic prostate cancer and second malignancy when compared with benign outcome. Conclusion Features that influence the probability of an incidental lesion representing a malignancy include lesion location, reason for the PSMA PET/CT study, and associated imaging features (size, standardized uptake value maximum, and molecular imaging PSMA score).

Structural and Dynamic Features of the Recognition of 8-oxoguanosine Paired with an 8-oxoG-clamp by Human 8-oxoguanine-DNA Glycosylase.

8-oxoguanine (oxoG) is formed in DNA by the action of reactive oxygen species. As a highly mutagenic and the most common oxidative DNA lesion, it is an important marker of oxidative stress. Human 8-oxoguanine-DNA glycosylase (OGG1) is responsible for its prompt removal in human cells. OGG1 is a bifunctional DNA glycosylase with N-glycosylase and AP lyase activities. Aspects of the detailed mechanism underlying the recognition of 8-oxoguanine among numerous intact bases and its subsequent interaction with the enzyme's active site amino acid residues are still debated. The main objective of our work was to determine the effect (structural and thermodynamic) of introducing an oxoG-clamp in model DNA substrates on the process of 8-oxoG excision by OGG1. Towards that end, we used DNA duplexes modeling OGG1-specific lesions: 8-oxoguanine or an apurinic/apyrimidinic site with either cytidine or the oxoG-clamp in the complementary strand opposite to the lesion. It was revealed that there was neither hydrolysis of the N-glycosidic bond at oxoG nor cleavage of the sugar-phosphate backbone during the reaction between OGG1 and oxoG-clamp-containing duplexes. Possible structural reasons for the absence of OGG1 enzymatic activity were studied via the stopped-flow kinetic approach and molecular dynamics simulations. The base opposite the damage was found to have a critical effect on the formation of the enzyme-substrate complex and the initiation of DNA cleavage. The oxoG-clamp residue prevented the eversion of the oxoG base into the OGG1 active site pocket and impeded the correct convergence of the apurinic/apyrimidinic site of DNA and the attacking nucleophilic group of the enzyme. An obtained three-dimensional model of the OGG1 complex with DNA containing the oxoG-clamp, together with kinetic data, allowed us to clarify the role of the contact of amino acid residues with DNA in the formation of (and rearrangements in) the enzyme-substrate complex.

Association between HIV Serostatus and premalignant cervical lesions among women attending a cervical cancer screening clinic at a tertiary care facility in southwestern Uganda: a comparative cross-sectional study

BackgroundUganda has approximately 1.2 million people aged 15–64 years living with human immunodeficiency virus (HIV). Previous studies have shown a higher prevalence of premalignant cervical lesions among HIV-positive women than among HIV-negative women. Additionally, HIV-infected women are more likely to have human papilloma virus (HPV) infection progress to cancer than women not infected with HIV. We determined the prevalence of premalignant cervical lesions and their association with HIV infection among women attending a cervical cancer screening clinic at Mbarara Regional Referral Hospital (MRRH) in southwestern Uganda.MethodsWe conducted a comparative cross-sectional study of 210 women aged 22–65 years living with HIV and 210 women not living with HIV who were systematically enrolled from March 2022 to May 2022. Participants were subjected to a structured interviewer-administered questionnaire to obtain their demographic and clinical data. Additionally, Papanicolaou smears were obtained for microscopy to observe premalignant cervical lesions. Multivariate logistic regression was performed to determine the association between HIV status and premalignant cervical lesions.ResultsThe overall prevalence of premalignant cervical lesions in the study population was 17% (n = 72; 95% C.I: 14.1–21.4), with 23% (n = 47; 95% C.I: 17.8–29.5) in women living with HIV and 12% (n = 25; 95% C.I: 8.2–17.1) in women not living with HIV (p < 0.003). The most common premalignant cervical lesions identified were low-grade squamous intraepithelial lesions (LSIL) in both women living with HIV (74.5%; n = 35) and women not living with HIV (80%; n = 20). HIV infection was significantly associated with premalignant lesions (aOR: 2.37, 95% CI: 1.27–4.42; p = 0.007).ConclusionPremalignant cervical lesions, particularly LSILs, were more common in HIV-positive women than in HIV-negative women, highlighting the need to strengthen the integration of cervical cancer prevention strategies into HIV care programs.

Branchial Cyst Masquerading as Myositis and Abscess of Sternocleidomastoid Muscle and Necrotic-Cystic Lymphadenopathy.

Branchial cleft cysts are considered one of the most common cystic lesions in neck and are commonly seen in pediatric age group and young adulthood with most of the cases presenting within second and third decade. Here we intend to discuss a case of a 43year old male who presented with a very short history of a painful lateral neck mass and was clinico-radiologically suggested as either myositis and abscess of sternocleidomastoid muscle or necrotic/cystic lymphadenopathy. An ultrasound guided needle aspiration cytology did not show any microorganism thus an excisional biopsy of the mass was done suspecting it to be lymph nodal mass. However the histopatholgical examination confirmed it to be an inflamed branchial cyst. Thus we would like to highlight the importance of keeping branchial cleft cysts as a possible differential while managing lateral neck masses of any duration in adults as well as in children.

Incidental finding of thyroglossal duct cyst in a neonate during endotracheal intubation: a case report

BackgroundThyroglossal Duct Cyst (TDC) is a common lesion of the midline neck, originating from an incomplete involution of the thyroglossal duct. It is typically observed in pre-scholar patients and surgery is the treatment of choice to prevent infections. Here reported a case of incidental diagnosis in a newborn patient.Case presentationa 3-week-old male baby was admitted to our hospital for weight loss and projectile vomits after breastfeeding. After a diagnosis of hypertrophic pyloric stenosis, the baby underwent pyloromyotomy. During the endotracheal tube placement, the anesthetist noticed the presence of a midline neck mass. The suspect of TDC was confirmed by an intraoperative ultrasound, so, despite the age of the patient, we proceeded with the excision of the lesion according to Sistrunk’s procedure to avoid future complications and anesthesia.Conclusionseven if TDC is a common lesion of pediatric patients, anecdotical neonatal cases were described in the literature, all of them symptomatic. An accurate physical examination and ultrasound are essential diagnostic tools to distinguish TDC from other middle neck lesions, particularly ectopic thyroidal tissue. Sistrunk’s procedure is the most effective surgical approach. When diagnosis is made in a newborn, we suggest postponing surgery, unless the baby requires general anesthesia for other surgical procedures, such as in our case.

Arachnoid cyst in the pediatric patient: What the radiologist needs to know.

Arachnoid cysts are the most common incidentally discovered intracranial lesions on imaging and the most common cystic intracranial lesions. They may be developmental or secondary. A relative lack of recent literature and any comprehensive radiological review on arachnoid cysts has led to a general lack of awareness among radiologists of symptomatic or complicated arachnoid cysts. This is particularly concerning in pediatric patients. While arachnoid cysts are asymptomatic in most cases, they can cause clinical symptoms in a minority of cases, especially when they occur in unusual sites. These include intraventricular locations where they may cause hydrocephalus, the basal cisterns where they may compress cranial nerves, the cerebellopontine angle where they have to be differentiated from a number of cystic lesions, the cavum septum pellucidum or cavum velum interpositum, the choroid fissure where they can entrap the temporal horn and compress the hippocampus, the posterior fossa where they need to be differentiated from other posterior fossa cystic lesions, and within the spinal canal where there is a concern for cord or nerve root compression. Larger cysts are more prone to complications such as mass effect, hemorrhage, and rupture. Hemorrhage and rupture often present with acute symptoms. Ruptured cysts lose their characteristic imaging appearance and can mimic several ominous pathologies. It therefore becomes vital to accurately diagnose these cases as complications of pre-existing arachnoid cysts for appropriate management. A detailed review of all diagnostic imaging aspects of arachnoid cysts will help fill in the existing information void on this important entity.

Imaging of pediatric gastrointestinal tumors: A tertiary center experience over 19 years

PurposeGastrointestinal tract (GIT) tumors in children are rare and there is a scarcity of data on their imaging features. The purpose of this study was to determine thefrequency of various GIT tumor types in children and to identify key imaging characteristics. MethodsThis retrospective, single-center study was approved by the local ethics committee. Children with histologically proven GIT tumours (malignantand benign) who had imaging available on the institutional PACS between May 1, 2000 and Dec 31, 2019 were included. Demographic data and available imaging was reviewed by two blinded radiologists. ResultsIn total, 90 children (45 male, mean age 9.3 ± 4.3 years) with GIT tumours were included. The final diagnoses included polyps (n = 28), lymphomas/PTLD (n = 27), neuroendocrine tumours (n = 16), adenocarcinoma (n = 6), adenoma (n = 5), gastrointestinal stromal tumor (GIST) (n = 3), inflammatory myofibroblastic tumours (n = 2) and lastly leiomyoblastoma, leiomyoma and lipoma (1 each). All GIT segments were affected, but overall the small and large bowel had most lesions. Eighty-one percent children had a single lesion while remaining 19 % had multiple lesions. The neoplastic process manifested as intra-luminal lesion (58 %) or wall thickening (42 %) on imaging. Multiple cystic areas and vascular pedicle for polyps; and hypoechogenecity of the mass or wall thickening and aneurysmal dilatation for lymphomas, were the characteristic imaging features. None of the neuroendocrine tumours affecting appendix were seen on pre-resection imaging. ConclusionsVariety of benign and malignant tumors are seen throughout the childhood. Polyps, lymphomas and appendiceal neuroendocrine tumors are common lesions. Characteristic imaging features of juvenile polyps and lymphomas on ultrasound may help narrowing the differentials, and guide further work up.

Oral cavity salivary gland pleomorphic adenoma: a histomorphological case series

BackgroundPleomorphic adenoma (PA), the most common benign salivary gland epithelial lesion, has a biphasic epithelial-mesenchymal pattern and great histopathological diversity. MethodsThis study's objective was to conduct a retrospective clinicopathological analysis, focusing on the histopathology characteristics of salivary gland PA. ResultsThere were ten cases of pleomorphic adenoma. The mean age was 33.5 years and no gender predilection was observed. All the patients presented with an asymptomatic mass and the duration of presentation was 31.2 ± 19.4 months. The cellular subtype (50 %) of PA was the most common. Capsular infiltration and incomplete capsules occurred in 20 % of cases. All the cases had round (100 %) and myxoid stroma.The cellular subtype was more common in the major salivary glands; showed capsular abnormalities (incomplete capsule, absent capsule, and tumor infiltration); and had more plasmacytoid, angular, spindled non-luminal cells as well as inflammation and cystic degeneration. The classic subtype had more clear and oncocytic cells along with sebaceous and squamous differentiation. The stroma-rich subtype had the shortest duration of complaints (three months) and showed giant cell reaction. ConclusionsThese findings confirm previous studies on the clinicopathological features of pleomorphic adenomas and highlight important morphologic characteristics like capsular invasion and squamous metaplasia, which can otherwise indicate malignancy.

Lesion Frequency Distribution Maps of Traumatic Axonal Injury on Early Magnetic Resonance Imaging After Moderate and Severe Traumatic Brain Injury and Associations to 12 Months Outcome.

Traumatic axonal injury (TAI) is a common finding on magnetic resonance imaging (MRI) in patients with moderate-severe traumatic brain injury (TBI), and the burden of TAI is associated with outcome in this patient group. Lesion mapping offers a way to combine imaging findings from numerous individual patients into common lesion maps where the findings from a whole patient cohort can be assessed. The aim of this study was to evaluate the spatial distribution of TAI lesions on different MRI sequences and its associations to outcome with use of lesion mapping. Included prospectively were 269 patients (8-70 years) with moderate or severe TBI and MRI within six weeks after injury. The TAI lesions were evaluated and manually segmented on fluid-attenuated inversed recovery (FLAIR), diffusion weighted imaging (DWI), and either T2* gradient echo (T2*GRE) or susceptibility weighted imaging (SWI). The segmentations were registered to the Montreal Neurological Institute space and combined to lesion frequency distribution maps. Outcome was assessed with Glasgow Outcome Scale Extended (GOSE) score at 12 months. The frequency and distribution of TAI was assessed qualitatively by visual reading. Univariable associations to outcome were assessed qualitatively by visual reading and also quantitatively with use of voxel-based lesion-symptom mapping (VLSM). The highest frequency of TAI was found in the posterior half of corpus callosum. The frequency of TAI was higher in the frontal and temporal lobes than in the parietal and occipital lobes, and in the upper parts of the brainstem than in the lower. At the group level, all voxels in mesencephalon had TAI on FLAIR. The patients with poorest outcome (GOSE scores ≤4) had higher frequencies of TAI. On VLSM, poor outcome was associated with TAI lesions bilaterally in the splenium, the right side of tectum, tegmental mesencephalon, and pons. In conclusion, we found higher frequency of TAI in posterior corpus callosum, and TAI in splenium, mesencephalon, and pons were associated with poor outcome. If lesion frequency distribution maps containing outcome information based on imaging findings from numerous patients in the future can be compared with the imaging findings from individual patients, it would offer a new tool in the clinical workup and outcome prediction of the patient with TBI.

Advancing Dermatological Diagnostics: Interpretable AI for Enhanced Skin Lesion Classification.

A crucial challenge in critical settings like medical diagnosis is making deep learning models used in decision-making systems interpretable. Efforts in Explainable Artificial Intelligence (XAI) are underway to address this challenge. Yet, many XAI methods are evaluated on broad classifiers and fail to address complex, real-world issues, such as medical diagnosis. In our study, we focus on enhancing user trust and confidence in automated AI decision-making systems, particularly for diagnosing skin lesions, by tailoring an XAI method to explain an AI model's ability to identify various skin lesion types. We generate explanations using synthetic images of skin lesions as examples and counterexamples, offering a method for practitioners to pinpoint the critical features influencing the classification outcome. A validation survey involving domain experts, novices, and laypersons has demonstrated that explanations increase trust and confidence in the automated decision system. Furthermore, our exploration of the model's latent space reveals clear separations among the most common skin lesion classes, a distinction that likely arises from the unique characteristics of each class and could assist in correcting frequent misdiagnoses by human professionals.