MRI Patterns in Pediatric CNS Hemophagocytic Lymphohistiocytosis

BACKGROUND AND PURPOSE

Neuroimaging has an important role in detecting CNS involvement in children with systemic or CNS isolated hemophagocytic lymphohistiocytosis. We characterized a cohort of pediatric patients with CNS hemophagocytic lymphohistiocytosis focusing on neuroradiologic features and assessed whether distinct MR imaging patterns and genotype correlations can be recognized.

MATERIALS AND METHODS

We retrospectively enrolled consecutive pediatric patients diagnosed with hemophagocytic lymphohistiocytosis with CNS involvement treated at 2 pediatric neurology centers between 2010 and 2018. Clinical and MR imaging data were analyzed.

RESULTS

Fifty-seven children (40 primary, 70%) with a median age of 36 months (interquartile range, 5.5-80.8 months) were included. One hundred twenty-three MR imaging studies were assessed, and 2 broad imaging patterns were identified. Pattern 1 (significant parenchymal disease, 32/57, 56%) was seen in older children (P = .004) with worse clinical profiles. It had 3 onset subpatterns: multifocal white matter lesions (21/32, 66%), brainstem predominant disease (5, 15%), and cerebellitis (6, 19%). All patients with the brainstem pattern failed to meet the radiologic criteria for chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids. An attenuated imaging phenotype (pattern 2) was seen in 25 patients (44%, 30 studies) and was associated with younger age.

CONCLUSIONS

Distinct MR imaging patterns correlating with clinical phenotypes and possible genetic underpinnings were recognized in this cohort of pediatric CNS hemophagocytic lymphohistiocytosis. Disruptive mutations and missense mutations with absent protein expression correlate with a younger onset age. Children with brainstem and cerebellitis patterns and a negative etiologic work-up require directed assessment for CNS hemophagocytic lymphohistiocytosis.

Pilomatricomas and café au lait macules as herald signs of constitutional mismatch repair deficiency (CMMRD) syndrome-A case report

Constitutional mismatch repair deficiency (CMMRD) syndrome results from bi-allelic mutations in DNA mismatch repair genes-MLH1, MSH2, MSH6, or PMS2. We present two siblings with CMMRD having p.Arg802Ter (c.2404C >T) homozygous mutations in PMS2 exon 14 with typical cutaneous features. This case report highlights the role of the dermatologist in early diagnosis of this condition.

An Unusual Cause of Chronic Headache in an Adolescent Boy: A Case Report

Spontaneous intracranial hypotension (SIH) is an under-diagnosed cause of headache in children and adolescents. SIH results from cerebrospinal fluid (CSF) leak due to breach in the dura mater and the etiology for dural breach is often diverse. We report an adolescent boy who presented with chronic episodic headache that later progressed to daily headache. There was a typical history of worsening of headache on upright position and relief of headache on lying down. He was treated with migraine prophylaxis in another hospital but there was no response. Marfanoid features and brisk deep tendon reflexes were observed on clinical examination. Brain magnetic resonance imaging (MRI) revealed sagging of the brain stem, pachymeningeal enhancement, and tonsillar herniation. MRI of spine myelogram confirmed multiple levels of CSF leak. He was initially managed with supportive measures and fluoroscopic-guided fibrin glue injection. Although child remained symptom-free for the next 6 months, he again developed headache. MRI and computed tomography spine myelogram revealed a meningeal diverticulum in the lumbar spine. He was managed with an autologous epidural blood patch and he has been well since then. In this report, we highlight the clinical and radiological pointers to the presence of SIH in children with recurrent headache.