Spontaneous Regression Research Articles

Integrative analysis with machine learning identifies diagnostic and prognostic signatures in neuroblastoma based on differentially DNA methylated enhancers between INSS stage 4 and 4S neuroblastoma

IntroductionAccumulating evidence demonstrates that aberrant methylation of enhancers is crucial in gene expression profiles across several cancers. However, the latent effect of differently expressed enhancers between INSS stage 4S and 4 neuroblastoma (NB) remains elusive.MethodsWe utilized the transcriptome and methylation data of stage 4S and 4 NB patients to perform Enhancer Linking by Methylation/Expression Relationships (ELMER) analysis, discovering a differently expressed motif within 67 enhancers between stage 4S and 4 NB. Harnessing the 67 motif genes, we established the INSS stage related signature (ISRS) by amalgamating 12 and 10 distinct machine learning (ML) algorithms across 113 and 101 ML combinations to precisely diagnose stage 4 NB among all NB patients and to predict the prognosis of NB patients. Based on risk scores calculated by prognostic ISRS, patients were categorized into high and low-risk groups according to median risk score. We conducted comprehensive comparisons between two risk groups, in terms of clinical applications, immune microenvironment, somatic mutations, immunotherapy, chemotherapy and single-cell analysis. Ultimately, we empirically validated the differential expressions of two ISRS model genes, CAMTA2 and FOXD1, through immunochemistry staining.ResultsThrough leave-one-out cross-validation, in both feature selection and model construction, we selected the random forest algorithm to diagnose stage 4 NB, and Enet algorithm to develop prognostic ISRS, due to their highest average C-index across five NB cohorts. After validations, the ISRS demonstrated a stable predictive capability, outperforming the previously published NB signatures and several clinic variables. We stratified NB patients into high and low-risk group based on median risk score, which showed the low-risk group with a superior survival outcome, an abundant immune infiltration, a decreased mutation landscape, and an enhanced sensitivity to immunotherapy. Single-cell analysis between two risk groups reveals biologically cellular variations underlying ISRS. Finally, we verified the significantly higher protein levels of CAMTA2 and FOXD1 in stage 4S NB, as well as their protective prognosis value in NB.ConclusionBased on multi-omics data and ML algorithms, we successfully developed the ISRS to enable accurate diagnosis and prognostic stratification in NB, which shed light on molecular mechanisms of spontaneous regression and clinical utilization of ISRS.

Advancements in elucidating the pathogenesis of actinic keratosis: present state and future prospects.

Solar keratosis, also known as actinic keratosis (AK), is becoming increasingly prevalent. It is a benign tumor that develops in the epidermis. Individuals with AK typically exhibit irregular, red, scaly bumps or patches as a result of prolonged exposure to UV rays. These growths primarily appear on sun-exposed areas of the skin such as the face, scalp, and hands. Presently, dermatologists are actively studying AK due to its rising incidence rate in the United States. However, the underlying causes of AK remain poorly understood. Previous research has indicated that the onset of AK involves various mechanisms including UV ray-induced inflammation, oxidative stress, complex mutagenesis, resulting immunosuppression, inhibited apoptosis, dysregulated cell cycle, altered cell proliferation, tissue remodeling, and human papillomavirus (HPV) infection. AK can develop in three ways: spontaneous regression, persistence, or progression into invasive cutaneous squamous cell carcinoma (cSCC). Multiple risk factors and diverse signaling pathways collectively contribute to its complex pathogenesis. To mitigate the risk of cancerous changes associated with long-term UV radiation exposure, prompt identification, management, and prevention of AK are crucial. The objective of this review is to elucidate the primary mechanisms underlying AK malignancy and identify potential treatment targets for dermatologists in clinical settings.

Clinical features and treatment options for pediatric adrenal incidentalomas: a retrospective single center study

BackgroundThe aim of this study was to investigate the clinical features and treatment options for pediatric adrenal incidentalomas(AIs) to guide the diagnosis and treatment of these tumors.MethodsThe clinical data of AI patients admitted to our hospital between December 2016 and December 2022 were collected and retrospectively analyzed. All patients were divided into neonatal and nonneonatal groups according to their age at the time of the initial consultation.ResultsIn the neonatal group, 13 patients were observed and followed up, and the masses completely disappeared in 8 patients and were significantly reduced in size in 5 patients compared with the previous findings. Four patients ultimately underwent surgery, and the postoperative pathological diagnosis was neuroblastoma in three patients and teratoma in one patient. In the nonneonatal group, there were 18 cases of benign tumors, including 9 cases of ganglioneuroma, 2 cases of adrenocortical adenoma, 2 cases of adrenal cyst, 2 cases of teratoma, 1 case of pheochromocytoma, 1 case of nerve sheath tumor, and 1 case of adrenal hemorrhage; and 20 cases of malignant tumors, including 10 cases of neuroblastoma, 9 cases of ganglioneuroblastoma, and 1 case of adrenocortical carcinoma.ConclusionsNeuroblastoma is the most common type of nonneonatal AI, and detailed laboratory investigations and imaging studies are recommended for aggressive evaluation and treatment in this population. The rate of spontaneous regression of AI is high in neonates, and close observation is feasible if the tumor is small, confined to the adrenal gland and has no distant metastasis.

Effect of Recent Antirheumatic Drug on Features of Rheumatoid Arthritis-Associated Lymphoproliferative Disorders.

In this study, we examine how advancements in novel antirheumatic drugs affect the clinicopathologic features of lymphoproliferative disorder (LPD) in patients with rheumatoid arthritis (RA). In this multicenter study across 53 hospitals in Japan, we characterized patients with RA who developed LPDs and visited the hospitals between January 1999 and March 2021. The statistical tools used included Fisher's exact test, the Mann-Whitney U-test, the log-rank test, logistic regression analysis, and Cox proportional hazards models. Overall, 752 patients with RA-associated LPD (RA-LPD) and 770 with sporadic LPD were included in the study. We observed significant differences in the clinicopathologic features between patients with RA-LPD and those with sporadic LPD. Histopathological analysis revealed a high frequency of LPD-associated immunosuppressive conditions. Furthermore, patients with RA-LPD were evaluated based on the antirheumatic drugs administered. The methotrexate (MTX) plus tacrolimus and MTX plus tumor necrosis factor inhibitor (TNFi) groups had different affected site frequencies and histologic subtypes than the MTX-only group. Moreover, MTX and TNFi may synergistically affect susceptibility to Epstein-Barr virus infection. In case of antirheumatic drugs administered after LPD onset, tocilizumab (TCZ)-only therapy was associated with lower frequency of regrowth after spontaneous regression than other regimens. Antirheumatic drugs administered before LPD onset may influence the clinicopathologic features of RA-LPD, with patterns changing over time. Furthermore, TCZ-only regimens are recommended after LPD onset.

Telomere maintenance mechanisms in neuroblastoma: New insights and translational implications

The clinical behaviour of neuroblastoma ranges from spontaneous tumour regression or maturation into benign ganglioneuroma to fatal progression despite intensive treatment [1,2]. The mechanisms underlying the distinct phenotypes have remained uncertain yet. A number of recent studies noticed that activation of telomere maintenance mechanisms (TMM) in the malignant neuroblasts is strongly associated with high-risk disease and poor outcome, whereas TMM are absent in spontaneously regressing low-risk tumours, suggesting that telomere maintenance is essential to drive neuroblasts into the fully malignant state. Stabilization of the telomeres above a critical threshold is essential for cancer cells to gain replicative immortality and has thus been considered a hallmark of cancer [3]. In most high-risk neuroblastomas, TMM is conferred by induction of telomerase, either through genomic rearrangements of the TERT locus, encoding for the catalytic subunit of telomerase, or amplification of the MYCN proto-oncogene, whereas the alternative lengthening of telomeres (ALT) pathway is activated in approximately one-quarter of high-risk tumours [4–8]. We here review recent advances on our understanding of the mechanistic role of telomere maintenance in neuroblastoma pathogenesis, and discuss potential implications on neuroblastoma risk assessment and on the development of novel therapies directed against TMM.

Medium-term effects of rapid maxillary expansion on nasal cavity and pharyngeal airway volumes considering age as a factor: A retrospective study

ObjectivesThe medium-term effects of rapid maxillary expansion (RME) on nasal cavity (NC) and upper airway (UA) dimensions based on chronological age are still unclear. This retrospective study evaluated the medium-term changes occurring in the NC and pharyngeal airways (PA) after RME in two distinct age-based cohorts of patients. MethodsThis retrospective study included 48 subjects who underwent RME grouped in two cohorts: a 6–9-year-old group (EEG group: early expansion group - 25 subjects) and an 11–14-year-old group (LEG group: late expansion group - 23 subjects). NC and PA volumes were analyzed from CBCT imaging segmentation before RME (T0) and twelve months after RME (T1). The amount of maxillary expansion (PW) and minimal cross-sectional area (CSmin) were also considered. ResultsAll PAs’ volumetric sub-regions, CSmin and PW showed a significant volumetric increment (p < 0.05). Inter-group comparisons showed significant differences (p < 0.05) for nasopharynx and CSmin parameters (p < 0.05), while no significant changes were recorded for the other UA's sub-regions and PW (p > 0.05). According to a deviation analysis, part of the UA increase (more marked for the nasopharynx area) may have occurred due to reduced adenotonsillar tissues, which were larger in the EEG group. ConclusionsTwelve months after treatment, clinicians should not expect changes in the UAs dimensions to be solely related to treatment effects of RME; instead, normal craniofacial growth changes and spontaneous regression of the adenotonsillar tissue could represent the most significant factors influencing UAs changes. Clinical SignificanceFrom the clinical perspective, the results of the present study encourage caution when considering the therapeutic effects of RME on airways dimensions.

Congenital pulmonary airway malformation with spontaneous regression in an extremely preterm baby from Sri Lanka

No abstract avialable

Analyses of tertiary lymphoid structures observed in cases of Merkel cell carcinoma showing spontaneous regression.

Merkel cell carcinoma (MCC) is a high-grade skin cancer, but spontaneous regression is observed at a markedly higher frequency than in other carcinomas. Although spontaneous regression is a phenomenon that greatly impacts treatment planning, we still cannot predict it. We previously reported on the prognostic impact of the presence or absence of tertiary lymphoid structures (TLS) and of Merkel cell polyomavirus (MCPyV) infection. To learn more about the spontaneous regression of MCC, detailed analyses were performed focusing on spontaneous regression cases. We collected 71 Japanese patients with MCC including 6 cases of spontaneous regression. Samples were analysed by immunostaining, spatial single-cell analysis using PhenoCycler, and RNA sequencing using the next-generation sequencer (NGS). All 6 cases of spontaneous regression were positive for MCPyV. TLS was positive in all 5 cases analysed. Spatial single-cell analyses revealed that PD-L1-positive tumour cells were in close proximity to CD20-positive B cell and CD3-, 4-positive T cells. Gene set enrichment analysis between MCPyV-positive and TLS-positive samples and other samples showed significantly high enrichment of "B-cell-mediated immunity" gene sets in the MCPyV-positive and TLS-positive groups. In conclusion, TLS may play an important role in the spontaneous regression of MCC.

De novo formation of remote dural arteriovenous fistula following treated cavernous sinus dural arteriovenous fistula

BackgroundThe development of new dural arteriovenous fistulas (DAVFs) at another location following endovascular treatment of cavernous sinus DAVFs (CSDAVFs) are extremely rare. Our aim is to review cases of de Novo DAVFs that occurred after treatment of CSDAVFs at our institution and those reported in the literature. MethodsWe reviewed all cases of CSDAVFs evaluated by 2 experienced neuroradiologists. A literature search was performed using the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines focusing on De Novo DAVFs following the endovascular treatment of cerebrovascular malformations. Addition articles were searched through the reference lists of the included articles. ResultsFrom June 2004 and September 2019., we identified 3 (2.5%) cases of De Novo DAVFs occurred after endovascular treatment or spontaneous obliteration of CSDAVFs from 119 treated CSDAVFs at our institute. Our review yielded 9 articles involving 12 patients with 15 de novo DAVFs, including our 3 patients. The mean age was 55.08 ± 12.9 years (range 43–69), 83.3% were females (n = 10). The new remote DAVFs occurred after endovascular treatment of CSDAVFs in 10 (83.3%) patients. The de novo DAVFs occurred following spontaneous complete regression in 2 (16.7%) patients. All de novo DAVFs developed after complete obliteration of treated CSDAVFs. ConclusionSinus thrombosis and elevated venous pressure may play an important role in the pathogenesis of a de novo DAVF formation. In addition, thrombophilic abnormalities and the use of contraceptives may contribute to sinus thrombosis, leading to the development of the second remote DAVF after treatment of CSDAVFs.

Hemorrhagic unilateral retinopathy: a report of multimodal imaging in three cases.

To report three cases of hemorrhagic unilateral retinopathy, diagnosed by multimodal imaging. Case report of 3 patients, 2 women and one man, aged 51, 74, and 52, respectively. Symptoms were acute floaters, blurred vision, or central scotoma, unilateral in all cases. The best-corrected visual acuity was 20/20 in the affected eye in 2 patients with a paracentral scotoma, and 20/160 in the third patient. Funduscopic examination revealed multiple unilateral posterior hemorrhages located in the Henle fiber layer in the macula and beneath the internal limiting membrane around the optic disc on spectral-domain optical coherence tomography (SD-OCT). Fluorescein angiography and indocyanine green angiography (ICGA) did not show any vascular abnormalities. SD-OCT angiography (SD-OCT-A) did not show any capillary drop-out or choroidal abnormalities. In all patients, the visual symptoms completely disappeared within a few weeks, with spontaneous regression of the hemorrhages. Hemorrhagic unilateral retinopathy is a rarely reported and poorly understood disorder. ICGA and SD-OCT-A did not allow better understanding the condition. No etiology has been associated with this entity so far. The spontaneous resolution of the present cases confirmed the favorable visual prognosis of the condition.

Residual cervical H-SIL after cervical conization with positive margins. Is there any associated risk factor?

Introduction: Cervical cancer is the second leading cause of death from gynecological cancer. In Argentina, it is estimated that nearly 4,500 new cases are diagnosed each year and 1,800 women die from this disease. The human papillomavirus (HPV) is a necessary but not a major cause to develop this type of cancer and it is responsible for producing both low-grade (L-SIL) and high-grade (H-SIL) squamous intraepithelial lesions (SIL) depending on the viral serotype in addition to other factors specific to the infected patient. Cervical intraepithelial neoplasia (CIN) is treated by local ablation or excision techniques with lower morbidity. The choice of treatment depends on the degree and extent of the disease, as well as the patient age, risk factors and immunity to generate spontaneous regression or persistence/recurrence. Objective: To identify clinical or pathological factors in patients who presented residual lesion (H-SIL) in the surgical specimens of both re-conization and hysterectomy (HT). Materials and methods: A retrospective, observational study was carried out at Sanatorio Güemes, Buenos Aires, Argentina. All patients that underwent cervical conization with an electric scalpel and had positive margins in the surgical specimen between January 2017 and May 2022 inclusive were analyzed. Data was obtained from 43 patients who had positive cervical conization specimen margins at our institution in the time period described above. Two patients who only had the exocervical margin involved and also 11 patients who did not meet the inclusion criteria were excluded. Among patients (30), all were reoperated (16 underwent re-conization, while in 14 patients it was decided to have a total hysterectomy). Among all the patients who underwent a new surgical procedure, residual disease was found in 10 patients (33.3%), while 20 patients (66.6%) had no residual lesion. Results: The highest percentage of patients (66.6%) did not present residual lesions in the posterior resection specimens. The parameter exhibiting the most substantial influence in our analysis was the proportion of lesion extension, exerting a significant effect on the persistence/recurrence of the disease in subsequent surgical samples (Relative Risk [RR] 7.87, 95% Confidence Interval [CI] 1.13-54.66, p &lt; 0.01). Conclusion: This information brings us even closer to the new reports of bibliographical data: although the presence of the compromised endocervical margin is valuable for estimating the risk of disease persistence/recurrence, it is not sufficient. Therefore, there is a lack of information about the importance of other factors to predict this situation.

A Case of Arteriovenous Malformation in the External Auditory Canal

Benign vascular tumors are relatively common in the head and neck region, but are rarely found in the ear. Among vascular tumors, infantile hemangioma stands as the prevailing entity, characterized by a rapid initial proliferation of endothelial cells, succeeded by a gradual regression over the course of several years. In contrast, arteriovenous malformation (AVM) is a less common phenomenon, originating from peripheral vascular anomalies during embryogenesis, and it does not undergo spontaneous regression. Specifically, the occurrence of AVM within the external auditory canal are exceedingly uncommon. Here, we describe a case of a 49-year-old male patient who had a mass incidentally discovered in the external auditory canal, but refused initial treatment. He later returned as the mass enlarged. This case could have been clinically misdiagnosed as a hemangioma, but was ultimately diagnosed pathologically as an AVM.

Brain stem tumors in children less than 3 months: Clinical and radiologic findings of a rare disease

PurposeBrain stem tumors in children < 3 months at diagnosis are extremely rare. Our aim is to study a retrospective cohort to improve the understanding of the disease course and guide patient management.MethodsThis is a multicenter retrospective analysis across the European Society for Pediatric Oncology SIOP-E HGG/DIPG Working Group linked centers, including patients with a brainstem tumor diagnosed between 2009 and 2020 and aged < 3 months at diagnosis. Clinical data were collected, and imaging characteristics were analyzed blindly and independently by two neuroradiologists.ResultsFive cases were identified. No patient received any therapy. The epicenter of two tumors was in the medulla oblongata alone and in the medulla oblongata and the pons in three. For patients with tumor in equal parts in the medulla oblongata and the pons (n = 3), the extension at diagnosis involved the spinal cord; for the two patients with the tumor epicenter in the medulla oblongata alone (n = 2), the extension at diagnosis included the pons (n = 2) and the spinal cord (n = 1). Biopsy was performed in one patient identifying a pilocytic astrocytoma. Two patients died. In one patient, autopsy revealed a high-grade glioma (case 3). Three survivors showed either spontaneous tumor regression (n = 2) or stable disease (n = 1). Survivors were followed up for 10, 7, and 0.6 years, respectively. One case had the typical imaging characteristics of a dorsal exophytic low-grade glioma.ConclusionsNo patient fulfilled the radiologic criteria defining a high-grade glioma. Central neuroradiological review and biopsy may provide useful information regarding the patient management.

Spontaneous regression of metastatic renal cell carcinoma after cytoreductive nephrectomy followed by relapse at 3 years.

Spontaneous regression of metastatic renal cell carcinoma after cytoreductive nephrectomy followed by relapse at 3 years.

Spontaneous regression of a giant uterine leiomyoma after delivery: a case report and literature review

BackgroundUterine leiomyomas are hormone-dependent benign tumors and often begin to shrink after menopause due to the reduction in ovarian steroids. The influence of pregnancy on uterine leiomyomas size remains unclear. Here, we present a case of spontaneous regression of a giant uterine leiomyoma after delivery.Case presentationA 40-year-old woman presented with multiple uterine leiomyomas, one of which is a giant uterine leiomyomas (approximately 8 cm in diameter) that gradually shrinked after delivery. At over two months postpartum, the large myometrial leiomyoma had transformed into a submucosal leiomyoma, and over 3 years postpartum, both the submucosal leiomyoma and multiple intramural leiomyomas completely regressed.ConclusionSpontaneous regression of a giant uterine leiomyom is rare after delivery. Considering uterine leiomyoma regression until over 3 year postpartum,we need to observe the regression of uterine fibroid for a longer time postpartum in the absence of fibroid related complications. In addition, it will provide new insights for treatment options of uterine leiomyomas in the future.

Abstract TP7: A Case Series of Spontaneous Thrombosis With a Conservative Approach to Posterior Spinal Artery Aneurysm Management

Ruptured spinal artery aneurysms, &lt;1% of SAH, pose challenges in understanding and management. In contrast to intracranial aneurysms, they often manifest with symptoms like back pain and possibly myelopathy. While morbidity and mortality seem low, limited data makes generalizations difficult. Fatalities have resulted from re-ruptures. Management options—surgical clipping, endovascular treatment, and conservative care—lack consensus. Surgical clipping appears to be most common, recommended for rebleeding prevention. However, some advocate conservative care due to spontaneous regression and low rebleeding risk. Our study presents five cases of spinal SAH from posterior spinal artery aneurysms. Patients aged 58-81, with three males and two females, who underwent spinal angiography and a repeat angiogram in 1-9 days between 2018 and 2022 at two Denver institutions. Notably, our study is the largest single practice case series to date. All patients initially reported back pain, with three experiencing leg paresthesias. One patient had confusion and a seizure. Four of the five were hypertensive. Crucially, all five patients achieved resolution and aneurysm occlusion on repeat angiograms. Our findings highlight the potential of conservative care for ruptured spinal artery aneurysms, with spontaneous thrombosis demonstrated on short-term follow-up angiograms. Based on our results, we propose a “hybrid” approach: starting with conservative management and angiographic follow-up in 3 to 7 days, typically when most aneurysms occlude. Clinical deterioration or persistent/worsening angiographic features at one week would prompt endovascular or surgical intervention as needed.

Pregnancy-Related Recurrent Benign Goiter With Intratracheal Extension.

This report describes the unique case of a 37-year-old pregnant patient with a history of total thyroidectomy who presented worsening dyspnea due to a recurrent benign goiter. The goiter grew through the tracheal wall and narrowed the tracheal lumen. After unsuccessful treatment with bronchodilators and corticosteroids, the patient underwent an emergency tracheostomy and cesarean section. Cervicothoracic computed tomography revealed a 4 cm mass in the left lobe of the thyroid gland with endotracheal extension in the subglottic region. Exploratory cervicectomy revealed a macroscopically resected mass that resembles the structure of the thyroid, adherent to the esophagus, anterior to the cricoid cartilage, and the trachea. Intratracheal thyroid tissue was not excised due to the increased risk of bleeding, and endoscopically guided biopsies were performed. Histopathological examination confirmed the benign nature of the thyroid tissue. A follow-up computed tomography scan after 2 months showed spontaneous regression of the intratracheal mass, and the tracheostomy tube was successfully removed without complications.

Desmoid Tumors: Current Perspective and Treatment.

Desmoid tumors are rare tumors with a tendency to infiltrate locally. The lack of a standard treatment approach makes choosing the most appropriate treatment for patients challenging. Most experts recommend watchful observation for asymptomatic patients as spontaneous regression of tumor is observed in up to 20% of patients. Upfront resection of the desmoid tumor has fallen out of favor due to high morbidity and high relapse rates associated with the tumor. Systemic therapy has evolved over several decades. Where chemotherapy, hormonal therapy, and non-steroidal anti-inflammatory drugs were used over the last several decades, tyrosine kinase inhibitors came to the forefront within the last decade. Most recently, gamma-secretase inhibitors have shown significant clinical benefit in patients with desmoid tumors, bringing forth an entirely new mechanistic approach. Several Wnt pathway inhibitors are also under development. Invasive approaches like cryoablation have also shown clinical benefit in patients with extra-abdominal desmoid tumors in recent years. The recent approval of nirogacestat has ushered in a new era of treatment for patients diagnosed with desmoid tumors. Several new molecules are expected to be approved over the coming years.

Сlinical case of visceral metastasis of cutaneous melanoma

Cutaneous melanoma is the most common tumor that metastasizes to the gastrointestinal tract, however, the diagnosis of visceral metastases remains difficult due to its low symptoms. Lifetime verification of melanoma metastases in the digestive tract is only 1–4%. Additional difficulties in verifying visceral melanoma metastases arise due to spontaneous regression of the primary tumor. The presented rare clinical case illustrates a variant of the course of disseminated melanoma of the skin with metastatic lesions of the gastrointestinal tract, while the dissemination was preceded by spontaneous regression of melanoma of the skin. Despite the lifetime endoscopic verification of multiple visceral metastases of cutaneous myeloma, the patient’s prognosis is unfavorable. The fact of spontaneous regression of cutaneous melanoma influenced the late diagnosis of melanoma dissemination, also due to the rarity of melanoma metastasis in the mucosa of the upper digestive tract, endoscopists are not sufficiently aware of endoscopic variants of melanoma metastases. It should be noted that endoscopic diagnostic methods must necessarily be included in the examination plan of a patient with melanoma, and when dynamically monitoring patients with melanoma after treatment, it is necessary to pay attention to non-specific signs of gastrointestinal tract damage (abdominal pain, anemia). In addition, in a patient with a history of melanoma, with endoscopic detection of an unpigmented neoplasm, it should be differentiated with a possible metastatic lesion, histological and immunohistochemical examination of the biopsy should be performed.

Acute appendicitis: A block-randomized study on active observation with or without antibiotic treatment

BackgroundAntibiotic treatment of unselected patients with acute appendicitis is safe and effective. However, it is unknown to what extent early provision of antibiotic treatment may represent overtreatment due to spontaneous healing of appendix inflammation. The aim of the present study was to evaluate the role of antibiotic treatment versus active in-hospital observation on spontaneous regression of acute appendicitis. MethodPatients who sought acute medical care at Sahlgrenska University Hospital were block-randomized according to age (18–60 years) and systemic inflammation (C-reactive protein <60 mg/L, white blood cell <13,000/μL), in combination with clinical and abdominal characteristics of acute appendicitis. Study patients received antibiotic treatment and active observation, while control patients were allocated to classic active “wait and see observation” for either disease regression or the need for surgical exploration. According to our standard surgical care, certified surgeons in charge decided whether and when appendectomy was necessary. In total, 1,019 patients were screened for eligibility; 203 patients met inclusion criteria, 126 were accepted to participate, 29 declined, and 48 were missed for inclusion. ResultsThe antibiotic group (n = 69) and the control group (n = 57) were comparable at inclusion. Appendectomy at first hospital stay was 28% and 53% for study and control patients (χ2, P < .004). Life table analysis indicated a time-dependent difference in the need for appendectomy during follow-up (P < .03). Antibiotics prevented surgical exploration and appendectomy by 72% to 50% compared to 47% to 37% in the control group across the time course follow-ups between 5 and 1,200 days. ConclusionEarly antibiotic treatment is superior to traditional “wait and see observation” to avoid surgical exploration and appendectomy.