SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance - Respiratory Virus Transmission Network, November 2022-May 2023.

As population immunity to SARS-CoV-2 evolves and new variants emerge, the role and accuracy of antigen tests remain active questions. To describe recent test performance, the detection of SARS-CoV-2 by antigen testing was compared with that by reverse transcription-polymerase chain reaction (RT-PCR) and viral culture testing during November 2022-May 2023. Participants who were enrolled in a household transmission study completed daily symptom diaries and collected two nasal swabs (tested for SARS-CoV-2 via RT-PCR, culture, and antigen tests) each day for 10 days after enrollment. Among participants with SARS-CoV-2 infection, the percentages of positive antigen, RT-PCR, and culture results were calculated each day from the onset of symptoms or, in asymptomatic persons, from the date of the first positive test result. Antigen test sensitivity was calculated using RT-PCR and viral culture as references. The peak percentage of positive antigen (59.0%) and RT-PCR (83.0%) results occurred 3 days after onset, and the peak percentage of positive culture results (52%) occurred 2 days after onset. The sensitivity of antigen tests was 47% (95% CI = 44%-50%) and 80% (95% CI = 76%-85%) using RT-PCR and culture, respectively, as references. Clinicians should be aware of the lower sensitivity of antigen testing compared with RT-PCR, which might lead to false-negative results. This finding has implications for timely initiation of SARS-CoV-2 antiviral treatment, when early diagnosis is essential; clinicians should consider RT-PCR for persons for whom antiviral treatment is recommended. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

Symptoms, viral loads, and rebound among COVID-19 outpatients treated with nirmatrelvir/ritonavir compared to propensity score matched untreated individuals.

BACKGROUND: Nirmatrelvir/ritonavir (N/R) reduces severe outcomes among patients with COVID-19; however, rebound after treatment has been reported. We compared symptom and viral dynamics in community-based individuals with COVID-19 who completed N/R and similar untreated individuals. METHODS: We identified symptomatic participants who tested SARS-CoV-2 positive and were N/R eligible from a COVID-19 household transmission study: index cases from ambulatory settings and their households were enrolled, collecting daily symptoms, medication use, and respiratory specimens for quantitative PCR for 10 days, March 2022-May 2023. Participants who completed N/R (treated) were propensity score matched to untreated participants. We compared symptom rebound, viral load (VL) rebound, average daily symptoms, and average daily VL by treatment status measured after N/R completion or, if untreated, seven days after symptom onset. RESULTS: Treated (n=130) and untreated participants (n=241) had similar baseline characteristics. After treatment completion, treated participants had greater occurrence of symptom rebound (32% vs 20%; p=0.009) and VL rebound (27% vs 7%; p<0.001). Average daily symptoms were lower among treated participants compared to untreated participants without symptom rebound (1.0 vs 1.6; p<0.01), but not statistically lower with symptom rebound (3.0 vs 3.4; p=0.5). Treated participants had lower average daily VLs without VL rebound (0.9 vs 2.6; p<0.01), but not statistically lower with VL rebound (4.8 vs 5.1; p=0.7). CONCLUSIONS: Individuals who completed N/R experienced fewer symptoms and lower VL but were more likely to have rebound compared to untreated individuals. Providers should still prescribe N/R, when indicated, and communicate possible increased rebound risk to patients.

Factors associated with mild bronchiolitis in young infants.

Objective: Bronchiolitis within the first 3 months of life is a risk factor for more severe illness. We aimed to identify characteristics associated with mild bronchiolitis in infants ≤90 days old presenting to the emergency department (ED). Methods: We conducted a secondary analysis of infants ≤90 days old with clinically diagnosed bronchiolitis using data from the 25th Multicenter Airway Research Collaboration prospective cohort study. We excluded infants with direct intensive care unit admissions. Mild bronchiolitis was defined as (1) sent home after the index ED visit and did not have a return ED visit or had a return ED visit without hospitalization, or (2) were hospitalized from the index ED visit to the inpatient floor for <24 hours. Multivariable logistic regression, adjusting for potential clustering by hospital site, was used to identify factors associated with mild bronchiolitis. Results: Of 373 infants aged ≤90 days, 333 were eligible for analysis. Of these, 155 (47%) infants had mild bronchiolitis, and none required mechanical ventilation. Adjusting for infant characteristics, clinical factors associated with mild bronchiolitis included older age (61-90 days vs 0-60 days) (odds ratio [OR] 2.72, 95% confidence interval [CI] 1.52-4.87), adequate oral intake (OR 4.48, 95% CI 2.08-9.66), and lowest ED oxygen saturation ≥94% (OR 3.12, 95% CI 1.55-6.30). Conclusions: Among infants aged ≤90 days presenting to the ED with bronchiolitis, about half had mild bronchiolitis. Mild illness was associated with older age (61-90 days), adequate oral intake, and oxygen saturation ≥94%. These predictors may help in the development of strategies to limit unnecessary hospitalization in young infants with bronchiolitis.

High-throughput Sequencing to Identify Bacteremia in Children with Cancer.

Current methods to diagnose bacteremia are limited. In this pilot study of children with cancer presenting with fever, we determined the concordance between a novel high-throughput sequencing platform called BacCapSeq and blood culture. High-throughput sequencing had modest concordance with blood culture. Discordant organisms included those with both unlikely or potential clinical relevance.

Household Transmission of Influenza A Viruses in 2021-2022.

Importance: Influenza virus infections declined globally during the COVID-19 pandemic. Loss of natural immunity from lower rates of influenza infection and documented antigenic changes in circulating viruses may have resulted in increased susceptibility to influenza virus infection during the 2021-2022 influenza season. Objective: To compare the risk of influenza virus infection among household contacts of patients with influenza during the 2021-2022 influenza season with risk of influenza virus infection among household contacts during influenza seasons before the COVID-19 pandemic in the US. Design, Setting, and Participants: This prospective study of influenza transmission enrolled households in 2 states before the COVID-19 pandemic (2017-2020) and in 4 US states during the 2021-2022 influenza season. Primary cases were individuals with the earliest laboratory-confirmed influenza A(H3N2) virus infection in a household. Household contacts were people living with the primary cases who self-collected nasal swabs daily for influenza molecular testing and completed symptom diaries daily for 5 to 10 days after enrollment. Exposures: Household contacts living with a primary case. Main Outcomes and Measures: Relative risk of laboratory-confirmed influenza A(H3N2) virus infection in household contacts during the 2021-2022 season compared with prepandemic seasons. Risk estimates were adjusted for age, vaccination status, frequency of interaction with the primary case, and household density. Subgroup analyses by age, vaccination status, and frequency of interaction with the primary case were also conducted. Results: During the prepandemic seasons, 152 primary cases (median age, 13 years; 3.9% Black; 52.0% female) and 353 household contacts (median age, 33 years; 2.8% Black; 54.1% female) were included and during the 2021-2022 influenza season, 84 primary cases (median age, 10 years; 13.1% Black; 52.4% female) and 186 household contacts (median age, 28.5 years; 14.0% Black; 63.4% female) were included in the analysis. During the prepandemic influenza seasons, 20.1% (71/353) of household contacts were infected with influenza A(H3N2) viruses compared with 50.0% (93/186) of household contacts in 2021-2022. The adjusted relative risk of A(H3N2) virus infection in 2021-2022 was 2.31 (95% CI, 1.86-2.86) compared with prepandemic seasons. Conclusions and Relevance: Among cohorts in 5 US states, there was a significantly increased risk of household transmission of influenza A(H3N2) in 2021-2022 compared with prepandemic seasons. Additional research is needed to understand reasons for this association.

Otologic Examination Findings In Afebrile Young Infants Clinically Diagnosed With Acute Otitis Media.

There are limited data on examination criteria for diagnosing acute otitis media in young infants. In this 33-site retrospective study of afebrile infants ≤90 days, clinicians typically documented tympanic membrane erythema with ≥1 other otologic abnormalities (64.1%) to diagnose acute otitis media. Notable differences in ear examination findings used for diagnosis existed across age subgroups.

Intranasal ketorolac versus intravenous ketorolac for treatment of migraine headaches in children: A randomized clinical trial.

BACKGROUND: Intravenous ketorolac is commonly used for treating migraine headaches in children. However, the prerequisite placement of an intravenous line can be technically challenging, time-consuming, and associated with pain and distress. Intranasal ketorolac may be an effective alternative that is needle-free and easier to administer. We aimed to determine whether intranasal ketorolac is non-inferior to intravenous ketorolac for reducing pain in children with migraine headaches. METHODS: We conducted a randomized double-blind non-inferiority clinical trial. Children aged 8-17 years with migraine headaches, moderate to severe pain, and requiring parenteral analgesics received intranasal ketorolac (1 mg/kg) or intravenous ketorolac (0.5 mg/kg). Primary outcome was reduction in pain at 60 min after administration measured using the Faces Pain Scale-Revised (scored 0-10). Non-inferiority margin was 2/10. Secondary outcomes included time to onset of clinically meaningful decrease in pain; ancillary emergency department outcomes (e.g. receipt of rescue medications, headache relief, headache freedom, percentage improvement); 24-h follow-up outcomes; functional disability; and adverse events. RESULTS: Fifty-nine children were enrolled. We analyzed 27 children who received intranasal ketorolac and 29 who received intravenous ketorolac. The difference in mean pain reduction at 60 min between groups was 0.2 (95% CI -0.9, 1.3), with the upper limit of the 95% CI being less than the non-inferiority margin. There were no statistical differences between groups for secondary outcomes. CONCLUSIONS: Intranasal ketorolac was non-inferior to intravenous ketorolac for reducing migraine headache pain in the emergency department.

Impact of Ondansetron Prescription on Return Emergency Department Visits Among Children with Acute Gastroenteritis.

OBJECTIVES: The objective of this study was to determine if providing ondansetron prescription to children with acute gastroenteritis seen in the emergency department (ED) is associated with reduced unscheduled ED revisits. METHODS: This was a retrospective comparative cohort study conducted in a tertiary urban pediatric ED. We evaluated otherwise healthy children 6 months to 18 years old who presented to the ED between 2010 and 2015 and were discharged home with acute gastroenteritis diagnosis. Illness severity was determined using dehydration score, emergency severity index, and presenting symptoms. The incidence of unscheduled 72-hour ED revisit among patients discharged home with ondansetron prescription was compared with those without a prescription. RESULTS: Of the 11,785 eligible patients, 35.5% (N = 4,187) of patients were discharged home with ondansetron prescription. After adjustment for emergency severity index, age, insurance source, race, time of index visit registration, intravenous fluid use, and ED-administered ondansetron, there were no differences in the rates of ED revisit (adjusted odds ratio [aOR] = 1.12 [0.92, 1.33]) or admission after ED revisit (aOR = 0.81 [0.51, 1.27]) among children with versus without ondansetron prescription. No difference was found in the proportion of alternative diagnoses among returning patients with versus without ondansetron prescription (aOR = 0.56 [0.20, 1.59]). CONCLUSIONS: There was no association between ondansetron prescription and ED revisit among children seen in the ED with suspected acute gastroenteritis. In the appropriate setting, however, physicians may consider prescribing ondansetron for symptom control in conjunction with careful discharge instructions.

Guideline Adherence in Diagnostic Testing and Treatment of Community-Acquired Pneumonia in Children.

OBJECTIVES: The objective of this study was to determine emergency department (ED) physician adherence with the 2011 Pediatric Infectious Diseases Society (PIDS) and Infectious Diseases Society of America (IDSA) guidelines for outpatient management of children with mild-to-moderate community-acquired pneumonia (CAP). METHODS: A cross-sectional survey of physicians on the American Academy of Pediatrics Section on Emergency Medicine Survey listserv was conducted. We evaluated ED physicians' reported adherence with the PIDS/IDSA guidelines through presentation of 4 clinical vignettes representing mild-to-moderate CAP of presumed viral (preschool-aged child), bacterial (preschool and school-aged child), and atypical bacterial (school-aged child) etiology. RESULTS: Of 120 respondents with analyzable data (31.4% response rate), use of chest radiograph (CXR) was nonadherent to the guidelines in greater than 50% of respondents for each of the 4 vignettes. Pediatric emergency medicine fellowship training was independently associated with increased CXR use in all vignettes, except for school-aged children with bacterial CAP. Guideline-recommended amoxicillin was selected to treat bacterial CAP by 91.7% of the respondents for preschool-aged children and by 75.8% for school-aged children. Macrolide monotherapy for atypical CAP was appropriately selected by 88.2% and was associated with obtaining a CXR (adjusted odds ratio, 3.9 [95% confidence interval, 1.4-11.1]). Guideline-adherent antibiotic use for all vignettes was independently associated with congruence between respondent's presumed diagnosis and the vignette's intended etiologic diagnosis. CONCLUSIONS: Reported ED CXR use in the management of outpatient CAP was often nonadherent to the PIDS/IDSA guidelines. Most respondents were adherent to the guidelines in their use of antibiotics. Strategies to increase diagnostic test accuracy are needed to improve adherence and reduce variation in care.

Invasive Bacterial Infections in Afebrile Infants Diagnosed With Acute Otitis Media.

OBJECTIVES: To determine the prevalence of invasive bacterial infections (IBIs) and adverse events in afebrile infants with acute otitis media (AOM). METHODS: We conducted a 33-site cross-sectional study of afebrile infants ≤90 days of age with AOM seen in emergency departments from 2007 to 2017. Eligible infants were identified using emergency department diagnosis codes and confirmed by chart review. IBIs (bacteremia and meningitis) were determined by the growth of pathogenic bacteria in blood or cerebrospinal fluid (CSF) culture. Adverse events were defined as substantial complications resulting from or potentially associated with AOM. We used generalized linear mixed-effects models to identify factors associated with IBI diagnostic testing, controlling for site-level clustering effect. RESULTS: Of 5270 infants screened, 1637 met study criteria. None of the 278 (0%; 95% confidence interval [CI]: 0%-1.4%) infants with blood cultures had bacteremia; 0 of 102 (0%; 95% CI: 0%-3.6%) with CSF cultures had bacterial meningitis; 2 of 645 (0.3%; 95% CI: 0.1%-1.1%) infants with 30-day follow-up had adverse events, including lymphadenitis (1) and culture-negative sepsis (1). Diagnostic testing for IBI varied across sites and by age; overall, 278 (17.0%) had blood cultures, and 102 (6.2%) had CSF cultures obtained. Compared with infants 0 to 28 days old, older infants were less likely to have blood cultures (P < .001) or CSF cultures (P < .001) obtained. CONCLUSION: Afebrile infants with clinician-diagnosed AOM have a low prevalence of IBIs and adverse events; therefore, outpatient management without diagnostic testing may be reasonable.

Presence and Duration of Symptoms in Febrile Infants With and Without SARS-CoV-2 Infection.

The clinical course of SARS-CoV-2 infection in young infants is not well understood. In this prospective cohort study, we compared the presence and duration of symptoms in febrile infants ≤60 days with (n = 7) and without (n = 16) SARS-CoV-2 infection. Overall, we observed overlapping symptoms and duration of illness, with longer length of cough and nasal congestion among the SARS-CoV-2-positive infants.

Novel Coronavirus Infection in Febrile Infants Aged 60 Days and Younger.

In this case series, we describe the clinical course and outcomes of 7 febrile infants aged ≤60 days with confirmed severe acute respiratory syndrome coronavirus 2 infection. No infant had severe outcomes, including the need for mechanical ventilation or ICU level of care. Two infants had concurrent urinary tract infections, which were treated with antibiotics. Although a small sample, our data suggest that febrile infants with severe acute respiratory syndrome coronavirus 2 infection often have mild illness.

WITHDRAWN: Comparison of Preadministered and Coadministered Lidocaine for Treating Pain and Distress Associated With Intranasal Midazolam Administration in Children: A Randomized Clinical Trial.

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Comparison of preadministered and coadministered lidocaine for treating pain and distress associated with intranasal midazolam administration in children: A randomized clinical trial.

OBJECTIVE: Pain and distress associated with intranasal midazolam administration can be decreased by administering lidocaine before intranasal midazolam (preadministered lidocaine) or combining lidocaine with midazolam in a single solution (coadministered lidocaine). We hypothesized coadministered lidocaine is non-inferior to preadministered lidocaine for decreasing pain and distress associated with intranasal midazolam administration. METHODS: Randomized, outcome assessor-blinded, noninferiority trial. Children aged 6 months to 7 years undergoing laceration repair received intranasal midazolam with preadministered or coadministered lidocaine. Pain and distress were evaluated with the Observational Scale of Behavioral Distress-Revised (OSBD-R) (primary outcome; non-inferiority margin 1.8 units) and the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and Faces, Legs, Activity, Cry, Consolability (FLACC) scales and cry duration (secondary outcomes). Secondary outcomes also included adverse events, clinician and caregiver satisfaction, and pain and distress associated with intranasal lidocaine administration. RESULTS: Fifty-one patients were analyzed. Mean OSBD-R scores associated with intranasal midazolam administration were 6.4 (95% confidence interval [CI] 5, 7.8) and 7 (95% CI 5.2, 8.9) units for preadministered and coadministered lidocaine, respectively. The difference of 0.6 (95% CI -1.7, 2.8) units represented an inconclusive non-inferiority determination. CHEOPS and FLACC scores and cry duration were similar between groups. OSBD-R, CHEOPS, and FLACC scores and cry duration associated with intranasal lidocaine administration were 3.8, 9.9, and 6 units, and 56 seconds, respectively. Clinicians considered coadministered lidocaine easier to administer. CONCLUSION: Pain and distress associated with intranasal midazolam administration were similar when using coadministered or preadministered lidocaine, but our non-inferiority determination was inconclusive. Administration of intranasal lidocaine by itself was associated with a measurable degree of pain and distress.Keywords: intranasal, midazolam, anxiolysis, sedation, emergency department, emergency medicine, pain, distress, pediatric, lidocaine, laceration.

Association Between Government Health Insurance Status and Physical Activity in American Youth.

BACKGROUND: Health insurance plans provide health programming access and affect physical activity levels in American youth, leading to health disparities in American children. The primary purpose of the current study was to investigate the relationship between health insurance status and physical activity level in American youth. METHODS: A national, United States census weighted cross-sectional survey was performed analyzing 2002 noninstitutionalized children living in the United States between the ages of 10 to 18 years, equally split by age and sex, with state of residency and race/ethnicity proportional to the 2010 census distribution. Multiple linear regression was performed to investigate the relationship between insurance status and activity level (measured by HSS Pedi-FABS activity score) while controlling for relevant demographic and socioeconomic covariables. RESULTS: HSS Pedi-FABS activity scores were normally distributed with a mean of 15.4±8.5 points (of 30 possible points). Patients with an insurance status of "government/Medicaid," "other," or "none" each demonstrated significantly lower physical activity scores (14.2±8.5 vs. 13.6±9.0 vs. 10.1±8.5) than children with private insurance (16.5±8.2) (one-way ANOVA with Dunnett-adjusted pairwise comparisons, P<0.001), which remained statistically significant while controlling for Area Deprivation Index, age, gender, race/ethnicity, and Body Mass Index (ß=-1.8, P<0.001). CONCLUSIONS: Government/Medicaid health insurance status and lack of health care coverage are associated with low levels of physical activity in American children, even while controlling for socioeconomic confounders. Collaborative work between health care providers and community/ school-based programs may be a reasonable approach to expanding access to recreation, organized sports, and physical activity for publicly and uninsured children. LEVEL OF EVIDENCE: Level II-Prognostic Study.

How Much Cerebrospinal Fluid Should We Remove Prior to Measuring a Closing Pressure?

OBJECTIVE: The objective of this study was to identify a relationship between cerebrospinal fluid (CSF) volume removal and change in CSF pressure in children with suspected idiopathic intracranial hypertension (IIH). METHODS: We performed a cross-sectional study of children 22 years and younger who underwent a lumbar puncture (LP) and had a documented opening pressure, closing pressure, and volume removed. Relationship between volume removal and pressure change was determined using a fractional polynomial regression procedure. RESULTS: In the 297 patients who met the inclusion criteria, CSF pressure decreased by 1 cm H2O for every 0.91 mL of CSF removed if the maximum change in pressure was less than 15 cm H2O ( R2 = 0.38). CONCLUSION: A linear relationship exists between the volume of CSF removed and the amount of pressure relieved when the desired pressure change is less than 15 cm H2O.

Low Vitamin D Levels in Children with Fractures: a Comparative Cohort Study.

BACKGROUND: The currently accepted ranges for "normal" serum vitamin D have recently been challenged in adults on the basis that healthy bone metabolism requires higher levels of vitamin D than previously thought. PURPOSE: The purpose of this study was to evaluate whether a new "biologically based" classification based on 25(OH)vitamin D levels that invoke an endocrine biomarker response (<20 ng/mL for deficiency and <32 ng/mL for insufficiency) is more appropriate for children with fractures than historical criteria. METHODS: Serum 25(OH)vitamin D levels were collected from 58 children with acute low-energy fractures from an outpatient orthopedic clinic from 2009 to 2012. These vitamin D levels were compared with a cohort of 103 children with chronic kidney disease (CKD) from an adjacent clinic, a condition with acknowledged low levels of vitamin D. Then, the prevalence of vitamin D sufficiency in the fracture cohort was evaluated and compared using both historical guidelines and newer biologically based criteria. RESULTS: 25(OH)vitamin D levels in the fracture cohort did not differ from levels in the CKD cohort (27.5 vs. 24.6 ng/mL) indicating a similar distribution of vitamin D levels. This finding was consistent when controlling for significant covariables using linear regression analyses. In the fracture cohort, there was a discrepancy between historical and biologically based criteria in 64% of children. CONCLUSIONS: The results of the current study suggest that fracture patients are more frequently vitamin D deficient than previously thought. This finding is more readily apparent when newer biologically based criteria for vitamin D sufficiency are used.

Hospital for Special Surgery Pediatric Functional Activity Brief Scale predicts physical fitness testing performance.

BACKGROUND: An eight-item activity scale was recently developed and validated for use as a prognostic tool in clinical research in children and adolescents. It is unclear, however, if this brief questionnaire is predictive of quantitative metrics of physical activity and fitness. QUESTIONS/PURPOSES: The purposes of this study were to prospectively administer the Hospital for Special Surgery Pediatric Functional Activity Brief Scale to a large cohort of healthy adolescents to determine (1) if the activity scale exhibits any floor or ceiling effects; (2) if scores on the activity scale are correlated with standardized physical fitness metrics; and if so, (3) to determine the discrimination ability of the activity scale to differentiate between adolescents with healthy or unhealthy levels of aerobic capacity and calculate an appropriate cutoff value for its use as a screening tool. METHODS: One hundred eighty-two adolescents (mean, 15.3 years old) prospectively completed the activity scale and four standardized metrics of physical fitness: pushups, sit-ups, shuttle run exercise (Progressive Aerobic Cardiovascular Endurance Run), and calculated VO2-max. Age, sex, and body mass index were also recorded. Pearson correlations, regression analyses, and receiver operating characteristic analyses were used to evaluate activity scale performance. RESULTS: The activity scale did not exhibit any floor or ceiling effects. Pushups (ρ = 0.28), sit-ups (ρ = 0.23), performance on the Progressive Aerobic Cardiovascular Endurance Run (ρ = 0.44), and VO2-max (ρ = 0.43) were all positively correlated with the activity scale score (Pearson correlations, all p < 0.001). Receiver operating characteristic analysis revealed that those with an activity score of ≤ 14 were at higher risk of having low levels of aerobic capacity. CONCLUSIONS: In the current study, activity score was free of floor and ceiling effects and predictive of all four physical fitness metrics. An activity score of ≤ 14 was associated with at-risk aerobic capacity previously shown to be associated with an increased risk of metabolic syndrome. This study is the first to prospectively validate an activity questionnaire against quantitative physical fitness assessments and provides further evidence substantiating its use in outcomes research and screening for healthy levels of childhood activity and fitness. LEVEL OF EVIDENCE: Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Genital melanocytic nevus arising in a background of lichen sclerosus in a 7-year-old female: the diagnostic pitfall with malignant melanoma. A literature review.

Genital melanocytic nevus represents a distinct form of melanocytic proliferation, which can exhibit significant atypia, both clinically and histologically. In a background of lichen sclerosus (LS), the histologic changes could be misconstrued as indicative of malignant melanoma. We present herein a case of the atypical genital nevus of childhood complicated by LS, and a review of the literature is performed. Tissue was available for routine light microscopy and immunohistochemical evaluation to assess the expression of soluble adenylyl cyclase. Fluorescent in situ hybridization studies were conducted to assess for abnormalities in Myb1, CCND1, RREB1 and CEP6. The specimen showed an atypical compound melanocytic proliferation arising in a background of LS. The lesion exhibited significant architectural atypia based on the high-density confluent nature of the junctional melanocytic proliferation with epidermal effacement, rare areas of pagetoid ascent, and the heavily pigmented epithelioid quality of the melanocytes. Fluorescent in situ hybridization studies were normal. The soluble adenylyl cyclase antibody preparation demonstrated a benign nevus-like pattern. The lesion was felt to represent an atypical genital melanocytic nevus, which can resemble a partially regressed melanoma in a background of LS. It is very important for the pathologist to be aware of this entity to avoid misdiagnosis.