Researchers at Hunan Children’s Hospital in Changsha, China, combined five of their own paediatric cases with a systematic review of published reports to quantify how often the condition masquerades as malignancy before a diagnosis is finally reached under the microscope.
The five institutional cases involved three boys and two girls aged between 4 and 12 years. Their lesions cropped up in strikingly different locations: the chest wall and pleural cavity, the spinal epidural space, Meckel’s cave at the skull base, the kidney, and the pineal region of the brain. Every lesion was mass-forming, and in three of the five children the initial radiological impression was suspicious for malignancy, while the other two showed other tumour-like growth patterns that still invited the wrong differential diagnosis.
Histopathology in all five cases revealed histiocytic proliferations, the expected signature of juvenile xanthogranuloma, with the markers CD68 or CD163 expressed by the lesional cells. Where testing was performed, CD1a and langerin were negative, helping to separate the entity from Langerhans cell histiocytosis. In one case, targeted sequencing detected a PIK3CA p.H1047R variant at a variant allele frequency of just 1.96 percent. The authors interpreted this finding cautiously as supportive rather than diagnostic, noting the low allele frequency and the absence of orthogonal validation.
To widen the picture beyond their own institution, the team conducted a PRISMA 2020-guided systematic review searching PubMed/MEDLINE, Embase and the Chinese CNKI database for literature published between January 2006 and September 2026, with no language restriction. After linking separate reports to individual patients, the review encompassed 150 publications corresponding to 147 unique patients with juvenile xanthogranuloma at uncommon anatomical sites.
The central result concerns how often these patients were first suspected of having cancer. Applying predefined criteria at the patient level, the researchers documented a malignancy-mimicking presentation before histopathological diagnosis in 15 of 147 patients, or 10.2 percent. A sensitivity analysis raised that figure to 17 of 147, or 11.6 percent. Crucially, the mistaken impression was not merely academic: diagnostic or management consequences were recorded in 11 of those 15 patients, amounting to 73.3 percent of the mimicry group.
The consequences could be serious. The review documents, among them, enucleation carried out for a lesion suspected of being retinoblastoma, the malignant eye tumour of early childhood.
The authors identify the recurring sources of diagnostic difficulty as unusual anatomical locations, tumour-like imaging findings, variable histopathological features, and overlap with other histiocytic disorders. Because juvenile xanthogranuloma is expected to be cutaneous and self-limited, a mass in the pineal region or the kidney rarely lands it on the initial differential, and the histological picture alone may not settle the matter. Their proposed answer is integration: diagnosis should draw together clinical, radiological, pathological and immunophenotypic data, with selective molecular testing added where available.
On molecular findings the study takes a deliberately conservative position. Molecular alterations may support the diagnosis, the authors write, but none is specific to juvenile xanthogranuloma, so sequencing results cannot carry the diagnosis on their own. The PIK3CA variant in their own case, at low variant allele frequency and unconfirmed by an orthogonal method, exemplifies why they urge restraint in over-reading such signals.
The team is candid about the limits of what they propose. Their diagnostic framework for distinguishing uncommon-site juvenile xanthogranuloma from malignancy and other tumour-like processes rests on small, heterogeneous case series and institutional experience, and they explicitly state it is not intended to serve as an evidence-based management standard.
What the study establishes is a quantified baseline: roughly one in ten children with juvenile xanthogranuloma at unusual sites presents in a way that mimics malignancy before tissue diagnosis, and for most of those children the mistaken impression changes what is done to them.
Subject of Research: Juvenile xanthogranuloma at uncommon anatomical sites in children and how often it mimics malignancy before histopathological diagnosis.
Article Title: Juvenile xanthogranuloma mimicking malignancy at uncommon sites in children: five cases and a systematic review
Article References: Zhang, S., Chen, W., Zhou, H., Ma, Q., Wen, R., & Du, L. (2026). Juvenile xanthogranuloma mimicking malignancy at uncommon sites in children: five cases and a systematic review. Frontiers in Oncology, 16, Article 1976218. https://doi.org/10.3389/fonc.2026.1976218
Image Credits: AI Generated
DOI: 10.3389/fonc.2026.1976218
Keywords: juvenile xanthogranuloma, pediatric oncology, histiocytic disorders, malignancy mimic, systematic review, differential diagnosis, CD68, CD163, PIK3CA, histopathology, retinoblastoma, diagnostic pitfall
News Source: Nathaniel Bowman. (October 29, 2026). Rare Childhood Tumour That Mimics Cancer Mapped in New Case Series and Review. Scienmag.
