Elevated taurine and glutamate in cerebral juvenile xanthogranuloma on MR spectroscopy

Neuroimaging manifestations of paediatric histiocytoses

Histiocytoses are rare multi-system disorders marked by abnormal histiocyte cell proliferation, affecting children with diverse clinical presentations. Classified into five groups in 2016, including Langerhans-related (L), cutaneous (C), malignant (M), Rosai-Dorfman disease (R) and haemophagocytic lymphohistiocytosis (H), newer entities such as ALK-positive histiocytosis have also emerged, heralding the era of molecular (sub)classification. Common entities include Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD) and haemophagocytic lymphohistiocytosis (HLH). This pictorial essay aids radiologists in recognising and differentiating paediatric histiocytoses based on unique neuroimaging features.

Central nervous system involvement of systemic ALK-positive histiocytosis with KIF5B-ALK fusion

ALK-positive histiocytosis is an emerging histiocytic entity that can involve a single organ or multiple organs. This disease frequently involves the central nervous system, and the importance of immunohistochemical and genetic analyses is emphasized for the accurate diagnosis of this rare entity. However, radiological findings of this disease have not been sufficiently described. Here, we report a case of a 3-year-old boy with ALK-positive histiocytosis with systemic masses that was identified to harbor KIF5B-ALK gene fusion.

Juvenile xanthogranuloma of the subdural spaces mimicking chronic hematoma with positive FDG uptake on PET: case report

The authors report an unusual presentation of juvenile xanthogranuloma (JXG), a non-Langerhans cell histiocytosis of infancy and early childhood. This entity typically presents as a cutaneous head or neck nodule but can manifest with more systemic involvement including in the central nervous system. However, currently there is limited information regarding specific imaging features differentiating JXG from other neuropathological entities, with diagnosis typically made only after tissue sampling. The authors reviewed the initial images of a young patient with shunt-treated hydrocephalus and enlarging, chronic, extraaxial processes presumed to reflect subdural collections from overshunting, and they examine the operative discovery of a mass lesion that was pathologically proven to be JXG. Their results incorporate the important associated histological and advanced imaging features, including previously unreported metabolic activity on FDG PET. Ultimately, the case underscores the need to consider JXG in differential diagnoses of pediatric intracranial masses and highlights the potential role of PET in the initial diagnosis and response to treatment.

Multimodel MRI features of an intracranial juvenile Xanthogranuloma

Juvenile xanthogranuloma (JXG) is a benign, self-limiting histiocytic disorder of infancy and early childhood, usually presented as a single or multiple cutaneous lesions. The central nervous system is rarely affected by JXG. There were only a few reports of intracranial JXG cases which described its features on MR spectroscopy (MRS) and diffusion-weighted imaging (DWI), but its features on susceptibility-weighted imaging (SWI) and perfusion-weighted imaging (PWI) have not been reported yet. Here, we reported an intracranial JXG case which underwent multimodal MRI examinations including DWI, SWI, and PWI. The multimodal MRI provided a thorough insight into this disease and we found that intense enhancement and high perfusion may be important clues for the diagnosis.

Intradural Juvenile Xanthogranuloma with Involvement of Multiple Nerve Roots: A Case Report and Review of the Literature

BACKGROUND

Juvenile xanthogranuloma (JXG) is a rare, non-Langerhans cell histiocytic disorder that primarily presents as multiple cutaneous lesions in young males. Solitary lesions in the spinal column are an especially rare presentation of this disease, and central nervous system involvement can portend a poor prognosis. We report an unusual case of an adult woman with an unresectable JXG of the lumbar spine. A review of the reported cases of thoracolumbar JXG and the current data regarding diagnosis and treatment are presented.

CASE DESCRIPTION

A 28-year-old woman presented with back pain and worsening lower extremity pain, numbness, and weakness. Magnetic resonance imaging demonstrated an enhancing lumbar mass. However, at surgery, no discrete mass was identified. Multiple roots were grossly enlarged, and electrical stimulation identified the L4 root with the most abnormal findings. Despite an attempt at debulking, most of the mass could not be safely removed. The patient experienced incomplete improvement of the symptoms postoperatively but elected to forgo chemotherapy. The 3-month follow-up imaging study showed active lumbar spinal disease, and imaging and follow-up examinations at 27 months revealed no changes. Her symptoms were satisfactorily controlled with conservative therapy.

CONCLUSIONS

JXG of the spine is a rare disease with nonspecific clinical and radiographic findings that can make it difficult to diagnose and dictates the use of immunohistochemical staining. If possible, total surgical resection will offer the best outcomes; however, other modalities such as chemotherapy can be viable alternatives or adjuvant modalities.