Transient Lesions Research Articles

Dermal toxicity studies of 1,2-benzisothiazolin-3-one (CAS number: 2634-33-5) in Sprague-Dawley rats

Biocides are used as preservatives in various household products, and 1,2-benzisothiazolin-3-one (BIT) is one of the popular chemicals. Therefore, BIT is highly likely to be exposed to human skin, necessitating dermal toxicity evaluation. In this study, we aimed to investigate dermal toxicity, eyes and skin irritation, and skin sensitization of BIT. All studies were conducted according to the Organisation for Economic Co-operation and Development testing guidelines. In acute dermal toxicity using rats, no treatment-related responses were observed at the highest dose (2000 mg/kg). A 28-day repeated dermal toxicity study at 1, 4, and 12 mg/kg/day showed transient local skin irritation lesions, including erythema, exfoliation, and crust formation. Based on no systemic effects, the no observed adverse effect level (NOAEL) of BIT of the 28-day repeated dermal toxicity study was determined to be 12 mg/kg/day. Eye and skin irritation tests showed that BIT is a strong irritant and corrosive to the eyes and a mild irritant to the skin. However, BIT showed no skin sensitization reactions in a local lymph node assay. These dermal toxicity studies can provide valuable information for the risk assessment of BIT.

Clinical Study of Cutaneous Manifestations in Neonates in A Tertiary Care Center in Eastern Nepal: A Descriptive Cross-sectional Study

Introduction: In the neonatal period, a variety of cutaneous symptoms are frequent. To minimize unneeded therapy and to reduce parents' stress, it's important to distinguish between transient and pathological newborn dermatoses. The purpose of this study is to describe the clinical pattern of cutaneous lesions in neonates. Methods: In this cross-sectional descriptive(IRC/1885/020) study , we enrolled 512 neonates born and admitted in maternal child health care ward and Post Natal ward of a tertiary health care cener irrespective of cutaneous manifestations. Convenience sampling technique was used. They were examined till their stay in hospital and followed up weekly via telephone for development of dermatological manifestations. Results: Out of 512 neonates examined, 415 (81.05%) of neonate had at least one cutaneous manifestation.393 (94.69%) had physiological skin lesions, 22 (5.31%) had pathological skin lesions. The most common physiological skin manifestations were sebaceous gland hyperplasia, mongolian spot, ETN, milia and epstein pearl. The pathological cutaneous manifestations though least common comprised of cradle cap, napkin dermatitis and bacterial infections. Most of the lesions were present within 24 hours of birth and many of them were physiological transient lesion. Conclusions: In conclusion, our study highlights the high prevalence of cutaneous manifestations in neonates, with the majority being physiological in nature. Medical personnel must be well versed in the skin changes of neonates which will further help prevent unnecessary treatment and identify life threatening situations that require additional attention.

Metronidazole‐induced encephalopathy with transient cortical lesions

Metronidazole‐induced encephalopathy with transient cortical lesions

Waxing and waning consciousness in a patient with a midbrain cavernous malformation: illustrative case.

Understanding the intricate relationship between consciousness and the midbrain's structures remains a significant challenge in neuroscience. Transient lesions are perfect examples of the physiological functioning mechanism of these structures. The authors present the case of a 49-year-old female who experienced a transient disorder of consciousness due to a midbrain hematoma following surgical interventions to remove a cavernous malformation in the midbrain. This case explores the interplay between the ascending reticular activating system (ARAS) and the thalamic centers, highlighting the role of structural disruptions in influencing consciousness levels. Notably, the patient's recovery correlated with the resolution of midbrain edema, reinstating normal ARAS function and consciousness. In patients affected by midbrain lesions, edema can lead to a fluctuating neurological status, which can be difficult to diagnose. This case highlights the midbrain's crucial role in the consciousness network and the need to comprehend the intricate connections between subcortical and cortical structures for a comprehensive understanding of human consciousness. https://thejns.org/doi/10.3171/CASE2411.

Efficacy of rituximab in the treatment of epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic mucocutaneous disease that is mediated by antibodies that bind collagen VII. The treatment of EBA can be challenging and often multiple immunomodulatory drugs are required. Rituximab has been reported to be an effective treatment for recalcitrant EBA, although its evidence base is limited to case reports and case series. This study therefore aimed to evaluate the efficacy of rituximab in patients with EBA. EBA patients treated with rituximab were identified by searching electronic medical records. Diagnostic criteria for EBA were as follows; mechanobullous skin lesions and / or mucosal ulceration, indirect immunofluorescence localising to the base of salt split skin and positive collagen VII antibodies. Clinical disease activity, collagen VII antibody levels and serum immunoglobulins were recorded at each follow up visit over 600 day period. Treatment responses were classified as follows; complete remission (CR) as the absence of new or established lesions on minimal therapy for 2 months, partial remission (PR) as transient lesions that heal within 1 week on minimal therapy and active disease (AD) as the development of new lesions. 14 patients with EBA were treated with rituximab. CR or PR was observed in 11 patients, and the duration of response varied between 4 and 24 months. A reduction in collagen VII antibody levels was observed in all patients. No significant adverse events were reported. Rituximab is a safe and effective treatment for patients with recalcitrant EBA although there was significant heterogeneity in the disease response.

COVID-19-Associated Cerebellar Ataxia: A Case Series.

COVID-19-associated cerebellar ataxia has rarely been reported and its clinical characteristics remain understudied. This study aims to report patients with COVID-19-associated cerebellar ataxia from our institution. COVID-19-associated cerebellar ataxia was diagnosed based on the prodromal COVID-19 infection and the exclusion of other causes. This study provides a summary of the patients' clinical presentations, neuroimaging features, and the results of anti-cerebellar antibody examinations. Our study included 11 patients and 4 were male. The median onset age was 38 years. Five patients also demonstrated signs of encephalopathy. Brain magnetic resonance imaging (MRI) was either unremarkable (n = 6) or showed bilateral cerebellar lesions (n = 5), which were typically transient, although brain atrophy could be observed later in the disease course. Anti-Homer-3 and anti-Yo antibodies were each detected in one patient, respectively. All patients received immunotherapy and nine improved. Compared with the late-onset group, individuals who exhibited ataxia earlier following COVID-19 onset (interval<5 days) were significantly younger [median age 18 (15.5-31) vs. 53.5 (44-64.8) years, p = 0.009] and more likely to present with encephalopathy (5/5 vs. 0/6, p = 0.002).They also experienced more severe symptoms [median modified Rankin scale (mRS) score at zenith 5 (5-5) vs. 2 (1.75-2.75), p = 0.017] and had a less favorable prognosis [median mRS score at the last follow-up 4 (2-5) vs. 1 (0-1.25), p = 0.009]. COVID-19-associated cerebellar ataxia can appear with encephalopathy. Brain MRI may show transient bilateral cerebellar lesions and brain atrophy later. Patients who exhibited ataxia earlier following COVID-19 were younger, had more severe symptoms and poorer outcomes.

Persistent Cutaneous Lesions of Darier Disease and Second-Hit Somatic Variants in ATP2A2 Gene

Darier disease (DD) is a rare genetic skin disorder caused by heterozygous variants in the ATP2A2 gene. Clinical manifestations include recurrent hyperkeratotic papules and plaques that occur mainly in seborrheic areas. Although some of the lesions wax and wane in response to environmental factors, others are severe and respond poorly to therapy. To investigate the molecular mechanism underlying the persistency of skin lesions in DD. In this case series, DNA was extracted from unaffected skin, transient and persistent lesional skin, and blood from 9 patients with DD. Genetic analysis was used using paired-whole exome sequencing of affected skin and blood or by deep sequencing of ATP2A2 of affected skin. Chromosomal microarray analysis was used to reveal copy number variants and loss of heterozygosity. All variants were validated by Sanger sequencing or restriction fragment length polymorphism. Paired whole-exome sequencing and deep sequencing of ATP2A2 gene from blood and skin samples isolated from persistent, transient lesions and unaffected skin in patients with DD. Germline and somatic genomic characteristics of persistent and transient cutaneous lesions in DD. Of 9 patients with DD, all had heterozygous pathogenic germline variants in the ATP2A2 gene, 6 were female. Participant age ranged from 40 to 69 years on enrollment. All 11 persistent skin lesions were associated with second-hit somatic variants in the ATP2A2 gene. The somatic variants were classified as highly deleterious via combined annotation-dependent depletion (CADD) scores or affect splicing, and 3 of them had been previously described in patients with DD and acrokeratosis verruciformis of Hopf. Second-hit variants in the ATP2A2 gene were not identified in the transient lesions (n = 2) or the normal skin (n = 2). In this study, persistent DD lesions were associated with the presence of second-hit somatic variants in the ATP2A2 gene. Identification of these second-hit variants offers valuable insight into the underlying mechanisms that contribute to the lasting nature of persistent DD lesions.

Neuroimaging findings in children with COVID-19 infection: a systematic review and meta-analysis

The COVID-19 pandemic has impacted individuals differently, and there's been a growing body of evidence pointing to neurological complications caused by the virus. However, our understanding of the range of neurological issues linked to SARS-CoV-2 infection in children is limited. This systematic review and meta-analysis aimed to assess the abnormal neuroimaging findings in pediatric COVID-19 patients, shedding light on this crucial aspect of the disease's impact on children. We conducted an extensive search in the PubMed, Medline, and ScienceDirect databases for observational studies reporting neuroimaging findings of the brain and spinal cord in children with COVID-19 between December 1, 2019, and October 30, 2021. Grey literature sources, including medRxiv and Google Scholar, were also explored. Pooled proportions of abnormal neuroimaging findings, categorized into neurovascular findings, ADEM-like lesions, encephalitic pattern, myelitis, transient splenial lesions, and other anomalies, were calculated using a random-effects model. Between-study heterogeneity was assessed using the χ2 statistic for pooled proportions and the inconsistency index I2. The Quality of the studies was evaluated using the NIH Quality Assessment Tool and the adapted Newcastle–Ottawa Scale. Our search yielded 9,605 articles, with 96 studies (involving 327 pediatric patients) included in the qualitative analysis. Of these, five reports (encompassing 111 patients) underwent quantitative analysis. The pooled proportion of pediatric COVID-19 patients with neurological symptoms and exhibiting abnormal neuroimaging findings was 43.74%. These findings were further categorized into neurovascular findings (8.22%), ADEM-like lesions (7.69%), encephalitic pattern (13.95%), myelitis (4.60%), transient splenial lesions (16.26%), and other abnormalities (12.03%). Insignificant between-study heterogeneity was observed in all categories, and our analysis did not reveal significant publication bias. In conclusion, a substantial proportion of pediatric COVID-19 patients with neurological symptoms have abnormal neuroimaging findings, underscoring the need for vigilant monitoring of neurological complications in this vulnerable population. Standardized reporting and long-term follow-up studies are essential to fully understand the implications of these findings. Collaborative research efforts will deepen our understanding of COVID-19's neurological dimensions in children and enhance clinical care for this population.

State of the art review. Complications after carpal tunnel release.

Carpal tunnel release (CTR) is the most performed surgery of the upper extremity. It is effective but not without complications. This state-of-the-art review covers most common intra- and postoperative complications after CTR. As endoscopic carpal tunnel release (ECTR) has developed over time, severe complications, such as nerve lesions, have diminished. ECTR still has a higher risk on transient nerve lesions. Open CTR on the other hand has a higher incidence of wound-related problems, including scar tenderness, irrespective of incision used. Most complications, such as pillar pain and infection, are ill-defined in the literature, leaving the exact incidence unknown and proposing challenges in treatment. The same is true for failure of treatment. Optimizing the length and location of incisions has played a vital role in reducing intra- and postoperative complications in CTR. It is expected that technical advances, such as ultrasound-guided percutaneous carpal tunnel release, will continue to play a role in the future.Level of evidence: V.

Chemotherapy-induced posterior reversible encephalopathy syndrome in an adolescent patient with acute lymphoblastic leukemia – A case report

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological condition characterized by headaches, seizures, confusion, and visual impairment. It typically causes transient lesions in the posterior white matter in magnetic resonance imaging (MRI) of the brain. PRES induced by chemotherapy is uncommon in oncology but can be a significant neurological event. The exact cause of PRES remains unclear. This case report describes a 15-year-old female patient with acute lymphoblastic leukemia who developed PRES following chemotherapy with prednisolone (100 mg), vincristine (2 mg), and daunorubicin (40 mg) as per the modified Berlin-Frankfurt-Munster (95/2002) protocol. She developed headaches, partial seizures, and elevated blood pressure 1 day after starting chemotherapy. Brain MRI showed T2 and fluid-attenuated inversion recovery hyperintensities in the bilateral cerebral parenchyma, brainstem, and cerebellum. She was treated with levetiracetam (500 mg stat and then 1.5 g BD) for seizures, amlodipine (5 mg) for hypertension, and paracetamol (650 mg TDS) for headaches. Her symptoms improved and resolved within 2 days. The event was deemed possibly related to the chemotherapy drugs according to the World Health Organization-Uppsala Monitoring Centre causality assessment system.

Efficacy and safety of surgical treatment of patients with pathological tortuosity of the internal carotid artery

Of the study is to improve the results of surgical treatment in patients with pathological tortuosity of the internal carotid artery. The study included 119 patients (41 (34%) men and 78 (66%) women) with PI ICA aged 34 to 71 years (average age 53.2±7.5 years) divided into 2 groups. 64 patients (54%) of group I underwent BSA resection with lower mouth and 55 patients (46%) of group II underwent BSA prosthetics. Depending on the degree of neurological disorders, patients were distributed according to the classification of A.V. Pokrovsky. In the early postoperative period, TIA was noted in one patient, and transient lesions of the cranial nerves were observed in 5 patients. During 5 years of follow-up, none of the patients developed TIA, IS or other vascular events. In the early surgical period, there were no significant differences in effectiveness between the groups of patients. In the long-term period (5 years after surgery), a higher frequency of asymptomatic patients was noted in group I. Resection and replacement of a pathologically tortuous internal carotid artery (ICA) is a safe and effective surgical treatment. A multicenter randomized trial should be conducted to compare the effectiveness of surgical treatment of PI ICA with a conservative approach to effectively treat patients.

Diagnosis of Transient Brain Lesion in the Corpus Callosum Splenium in Emergency Service and Elucidation of Accompanying Conditions

Corpus Callosum Cytotoxic Lesion (CLOCCs) once rarely seen in the literature has been more often diagnosed in emergency services nowadays with widespread use of cranial magnetic resonance imaging (MRI). CLOCCs is defined as a clinical and radiological spectrum disorder. Patient’s neurological symptoms usually improve completely within 1 month after the onset of the disease without any sequel. This is generally associated with cytotoxic edema of the splenium corpus callosum. It is important investigate the primary causes that lead to this condition and start the appropriate treatment according to the real diagnosis. We present a case diagnosed as CLOCCs secondary to pneumonia upon admission to our emergency service.

Super transient splenial lesion of the corpus callosum in a patient with COVID-19 infection and superimposed bacteremia

Super transient splenial lesion of the corpus callosum in a patient with COVID-19 infection and superimposed bacteremia

Reversible Splenial Corpus Callosum Lesion and Carbamazepine

Introductıon&#x0D; Reversible splenial lesion syndrome (RESLES) at corpus callosum (CC) has been defined in many clinical conditions. Although the etiopathogenesis of transient focal lesions in the CC splenium has not been clarified, many theories remain on the agenda, especially in epilepsy patients.&#x0D; Case&#x0D; A 38-year-old male patient with idiopathic generalized epilepsy was admitted to the emergency department with complaints of frequent seizures. It was reported by his relatives that he had stopped carbamazepine treatment for the last three days. After his last epileptic attack, he had been headache, nausea, vomiting, decreased visual acuity, and prolonged confusion. The patient with diffusion restriction at the level of splenium CC in magnetic resonance imaging (MRI), whose seizure frequency increased, was evaluated by a neurology doctor. In his electroencephalography, spike waves were observed in both hemispheres, which were frequently generalized. The same lesion was not observed in the diffusion and MRI taken eight days later in the patient who had no seizures in the follow-up.&#x0D; Discussion&#x0D; Studies have shown that CC damage results in the disruption of cortical functions, with disconnection of the cerebral hemispheres and disturbances in consciousness. The clinical spectrum includes a fairly wide symptomatology. RESLES of the CC is an infrequent finding on MRI. Some of these lesions are associated with epileptic seizures, the sudden withdrawal of the antiepileptic drug, or usage.&#x0D; Conclusion&#x0D; RESLES, which we reviewed with etiology and clinical findings, still remains a mystery. It will be clarified with wide-ranging studies.

Reversible Splenial Lesion Syndrome (RESLES) in Sickle Cell Crisis Mimicking Marchiafava-Bignami Disease (P10-7.001)

<h3>Objective:</h3> N/A <h3>Background:</h3> Reversible Splenial Lesion Syndrome (RESLES) is characterized by the presence of transient lesion involving the splenium of corpus callosum in patients with encephalopathies of various cytotoxic etiologies. One of which is Marchiafava-Bignami Disease(MBD), which could manifest with sudden stupor or coma in alcohol use disorder (AUD) or malnutrition with severe demyelination of splenium. Here we report a case of MBD-like presentation in a patient with vaso-occlusive sickle-cell crises. <h3>Design/Methods:</h3> NA <h3>Results:</h3> A 46-year-old male with sickle-cell disease and no history of AUD presented with acute chest syndrome with pain crisis. He was treated with blood transfusion and analgesics. Two days later, he became acutely unresponsive with right-sided hemiparesis, requiring intubation. MRI brain showed numerous punctate infarcts in the watershed areas bilaterally, along with symmetric diffusion restriction in the splenium of corpus callosum, respecting its anatomic boundary. Exchange transfusion was initiated and maintained his hemoglobin &gt;10 g/dL and Hb-SS &lt; 30%, but he remained comatose (GCS 6). Electroencephalogram showed diffuse cerebral dysfunction without epileptogenicity. His extensive infectious workup was unremarkable. Other laboratory tests including electrolytes, liver function tests, ammonia, thyroid function tests, vitamin B12, B6, folic acid, and thiamine levels were normal. He was empirically treated with intravenous thiamine. One week later, his mental status improved to following commands. MRI brain two weeks after showed a near-complete resolution of the callosal lesion. The patient’s acute stupor/coma and MRI findings were attributed to hypoxic watershed infarcts and RESLES due to hypoxic stress from vaso-occlusive sickle cell crisis, leading to a transient coma, mimicking MBD. <h3>Conclusions:</h3> RESLES is a distinct syndrome with characteristic radiographic finding of diffusion restriction in the splenium of corpus callosum due to cytotoxic edema of various etiologies. MBD is one such example, presenting with stupor/coma. This case emphasizes the importance of identifying reversible metabolic stressors, including sickle cell crisis. <b>Disclosure:</b> Dr. Mulatu has nothing to disclose. Dr. Yoon has received personal compensation in the range of $500-$4,999 for serving as a Consultant for ECHAS. Dr. Ramaswamy has nothing to disclose. Dr. Mulatu has nothing to disclose. Cappi C Lay has received publishing royalties from a publication relating to health care.

Early and late contrast enhancing lesions after photon radiotherapy for IDH mutated grade 2 diffuse glioma

ObjectiveThe interpretation of new enhancing lesions after radiotherapy for diffuse glioma remains a clinical challenge. We sought to characterize and classify new contrast enhancing lesions in a historical multicenter cohort of patients with IDH mutated grade 2 diffuse glioma treated with photon therapy. MethodsWe reviewed all follow-up MRI’s of all patients treated with radiotherapy for histologically confirmed, IDH mutated diffuse grade 2 glioma between 1–1-2007 and 31–12-2018 in two tertiary referral centers. Disease progression (PD) was defined in accordance with the RANO criteria for progressive disease in low grade glioma. Pseudoprogression (psPD) was defined as any transient contrast-enhancing lesion between the end of radiotherapy and PD, or any new contrast-enhancing lesion that remained stable over a period of 12 months in patients who did not exhibit PD. ResultsA total of 860 MRI’s of 106 patients were reviewed. psPD was identified in 24 patients (23%) on 76 MRI’s. The cumulative incidence of psPD was 13% at 1 year, 22% at 5 years, and 28% at 10 years. The mean of the observed maximal volume of psPD was 2.4 cc. The median Dmin in psPD lesions was 50.1 Gy. The presence of an 1p/19q codeletion was associated with an increased risk of psPD (subhazard ratio 2.34, p = 0.048). psPD was asymptomatic in 83% of patients. ConclusionThe cumulative incidence of psPD in grade 2 diffuse glioma increases over time. Consensus regarding event definition and statistical analysis is needed for comparisons between series investigating psPD.

A narrative review of the clinical approach to subsolid pulmonary nodules.

The widespread use of chest computed tomography (CT) for lung cancer screening has led to increased detection of subsolid pulmonary nodules. The management of subsolid nodules (SSNs) is challenging since they are likely to grow slowly and a long-term follow-up is needed. In this review, we discuss the characteristics, natural history, genetic features, surveillance, and management of SSNs. PubMed and Google Scholar were searched to identify relevant articles published in English between January 1998 and December 2022 using the following keywords: "subsolid nodule", "ground-glass nodule (GGN)", and "part-solid nodule (PSN)". The differential diagnosis of SSNs includes transient inflammatory lesions, focal fibrosis, and premalignant or malignant lesions. Long-term CT surveillance follow-up is needed to manage SSNs that persist for >3 months. Although most SSNs have an indolent clinical course, PSNs may have a more aggressive clinical course than pure GGNs. The proportion of growth and the time to grow is higher and shorter in PSN than pure GGN. In lung adenocarcinoma manifesting as SSNs, EGFR mutations were the major driver mutations. Guidelines are available for the management of incidentally detected and screening-detected SSNs. The size, solidity, location, and number of SSNs are important factors in determining the need for surveillance and surgical resection, as well as the interval of follow-up. Positron emission tomography/CT and brain magnetic resonance imaging (MRI) are not recommended for the diagnosis of SSNs, especially for pure GGNs. Periodic CT surveillance and lung-sparing surgery are the main strategies for the management of persistent SSNs. Nonsurgical treatment options for persistent SSNs include stereotactic body radiotherapy (SBRT) and radiofrequency ablation (RFA). For multifocal SSNs, the timing of repeated CT scans and the need for surgical treatment are decided based on the most dominant SSN(s). The SSN is a heterogeneous disease and a personalized medicine approach is required in the future. Future studies of SSNs should focus on their natural history, optimal follow-up duration, genetic features, and surgical and nonsurgical treatments to improve the corresponding clinical management. All these efforts will lead to the personalized medicine approach for the SSNs.

Progress towards a standardized model of ocular sulfur mustard injury for therapeutic testing

Sulfur mustard (SM) remains a highly dangerous chemical weapon capable of producing mass casualties through liquid or vapor exposure. The cornea is highly sensitive to SM toxicity and exposure to low vapor doses can cause incapacitating acute injuries. At higher doses, corneas fail to fully heal and subsequently develop a constellation of symptoms known as mustard gas keratopathy (MGK) that causes reduced quality of life and impaired or lost vision. Despite a century of research, there are no specific treatments for acute or persistent ocular SM injuries. Here I summarize toxicological, clinical and pathophysiological mechanisms of SM vapor injury in the cornea, describe a preclinical model of ocular SM vapor exposure for reproducible therapeutic studies, and propose new approaches to improve evaluation of therapeutic effects. I also describe recent findings illustrating the delayed development of a transient but severe recurrent corneal lesion that, in turn, triggers the emergence of secondary keratopathies characteristic of the chronic form of MGK. Development of this recurrent lesion is SM dose-dependent, although the severity of the recurrent lesion appears SM dose-independent. Similar recurrent lesions have been reported in multiple species, including humans. Given the mechanistic relationship between the recurrent lesion and chronic, secondary keratopathies, I hypothesize that preventing the development of the recurrent lesion represents a novel and potentially valuable therapeutic approach for treatment of severe corneal SM injuries. Although ocular exposure to SM vapor continues to be a challenging therapeutic target, establishing consistent and reproducible models of corneal injury that enhance mechanistic and pathophysiological understanding will help satisfy regulatory requirements and accelerate the development of effective therapies.

USP6-associated neoplasm as a tentative subset of postoperative spindle cell nodule.

Postoperative spindle cell nodule (PSCN) is a pseudosarcomatous proliferative lesion of unclear molecular genetic origins. We examined seven patients with PSCN, using routine haematoxylin-eosin (H&E) slide preparations and a series of immunostains. The latter targeted keratin, vimentin, α-smooth muscle actin (SMA), anaplastic lymphoma kinase (ALK [D5F3]), and other proteins. Ubiquitin-specific peptidase 6 (USP6) and anaplastic lymphoma kinase (ALK) gene rearrangements were also analysed by fluorescence insitu hybridization (FISH). There were histories of prior surgical intervention (n=6) or trauma (n=1) in all seven patients. All lesions were highly cellular and mitotically active spindle cell proliferations, with no cytologic atypia, nuclear pleomorphism, or aberrant mitoses. Immunohistochemical (IHC) staining disclosed focal, weak keratin positivity in two lesions, whereas vimentin (diffuse, strongly positive) and SMA (tram-track pattern) were present in each instance, and ALK (D5F3) was entirely negative. FISH analysis confirmed USP6 gene rearrangements in all seven cases, showing no ALK gene rearrangements. RNA sequencing results showed an MYH9::USP6 gene fusion in only one lesion (No. 6). A subset of PSCN is marked by USP6 gene rearrangements, a genetic feature of nodular fasciitis (NF). Given its similarity to NF, a designation as USP6-associated neoplasm (UAN) seems reasonable, signifying a transient clonal neoplastic lesion.

Transient splenial lesion as late complication of COVID-19 infection.

Transient splenial lesion as late complication of COVID-19 infection.