Papillon–Lefèvre Syndrome Unmasked by Atypical Cat Scratch Disease

To the Editors: Papillon–Lefèvre syndrome (PLS) is a rare autosomal recessive disorder characterized by palmoplantar keratoderma, periodontitis and premature loss of dentition, caused by CTSC mutations leading to defective neutrophil function and increased susceptibility to infections.1 While recurrent bacterial liver abscesses are described, visceral involvement due to atypical pathogens is rarely reported. We describe an 8-year-old boy, born of nonconsanguineous parentage, who presented with fever and right upper quadrant abdominal pain. He had a history of 3 prior episodes of liver abscess since early childhood. Clinical examination revealed sharply demarcated keratotic plaques on the palms and soles and severe periodontitis with loose teeth (Fig. 1A, B), raising suspicion of PLS. Laboratory evaluation showed raised C-reactive protein with otherwise normal hematologic and immunologic parameters. Magnetic resonance imaging (Fig. 2) revealed a multiloculated abscess in segment V of the liver with features of hepatic venous outflow obstruction. Positron emission tomography (Fig. 1C) revealed irregular avid uptake. Pus aspirate was sterile. Despite broad-spectrum antibiotics, the child remained febrile. Serological testing for atypical organisms revealed strongly positive Bartonella henselae IgM and IgG titers. Based on this, doxycycline and rifampicin were initiated, leading to complete resolution of fever within 48 hours and significant radiological regression of the abscess at follow-up. Genetic analysis confirmed a pathogenic nonsense mutation in exon 5 of CTSC, establishing the diagnosis of PLS. The patient's recurrent liver abscesses, cutaneous and dental findings and immunological dysfunction were consistent with this syndrome.2 Liver abscesses are rare complications in PLS, with only around 22 cases described worldwide.3 Most reported pathogens include Staphylococcus aureus and Escherichia coli; atypical organisms such as Rhizopus oryzae have also been implicated.4 To our knowledge, B. henselae has not been previously reported as a cause of hepatic abscess in PLS. Typical cat scratch disease (CSD) manifests with regional lymphadenopathy, while atypical or disseminated forms may involve hepatosplenic abscesses, usually in immunocompromised hosts.5 Our case highlights an unusual manifestation—isolated hepatic abscess without lymphadenopathy—underscoring the need for suspicion in atypical presentations. Diagnosis of CSD relies on clinical context, serology and occasionally polymerase chain reaction. In our case, strongly positive serology with a rapid therapeutic response supported the diagnosis. Combination therapy with rifampicin and doxycycline has proven efficacy in disseminated disease and, in this instance, led to an excellent clinical outcome. This case underscores several important points. First, recurrent deep-seated infections in children should prompt evaluation for syndromic immunodeficiencies such as PLS. Second, unusual pathogens such as B. henselae should be considered in immunocompromised hosts presenting with visceral abscesses, even in the absence of classical features of CSD. Finally, multidisciplinary collaboration between infectious disease specialists, hepatologists, dermatologists and geneticists is crucial for diagnosis and management in such complex cases. In summary, we present the first reported association between PLS and B. henselae hepatic abscess. Awareness of this atypical presentation is important for timely recognition and treatment.FIGURE 1.: A: Well-demarcated shiny scaly keratotic plaque involving the dorsum of the right hand. B: Carious lesions involving upper and lower canines (yellow arrows) along with dental crowding. C: PET scan image showing isolated FDG avid uptake in a circumscribed, irregular lesion in the liver. FDG indicates fluorodeoxyglucose; PET, positron emission tomography.FIGURE 2.: Axial (A, B) and coronal (C) T2-weighted MRI images demonstrate a single large, well-defined T2 intermediate mass lesion (marked with a white arrow) in segments V and VI of the liver with minimal perilesional T2 hyperintense edema. The center of the lesion shows diffusion restriction, appearing bright on DWI (D) with a loss of signal on the corresponding ADC map (E). Postcontrast image (F) shows peripheral rim enhancement and multiple septations within the lesion. The underlying liver appears dysmorphic with hypertrophied caudate lobe (*) and caudate vein (arrowhead), and multiple intrahepatic collaterals suggestive of a diagnosis of hepatic venous outflow tract obstruction (B). ADC indicates apparent diffusion coefficient; DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging.