Five year old boy with progressive headache since one month. Vomiting. Weight Loss.
Diffuse homogeneous abnormal spinal cord uptake (SUVmax 2.5). No other suspicious lesion.
Primary diffuse leptomeningeal gliomatosis
Primary diffuse leptomeningeal atypical teratoid rhabdoid tumor
Atypical rhabdoid/teratoid tumor (AT/RT) is a highly malignant tumor accounting for 10% of central nervous system tumors in infants. This neoplasia is characterized histologically bynests or sheets of rhabdoid tumor cells with varying proportions of primitive neuroectodermal tumor (PNET) cells, mesenchymal spindle-shaped tumor cells, and/or epithelial-type tumor cells.
This tumor has aggressive growth with high potential for dissemination and poor prognosis.
In children, the most common primary site is the cerebellum. Leptomeningeal spread is a well known aggressive clinical course of AT/RT and is reported to occur in one third of paediatric cases at presentation. However, a focal parenchymal lesion is usually present.
At the present, there are only four cases of primary diffuse leptomeningeal atypical teratoid/rhabdoid tumor reported in the literature.
There was no other primary site to support the leptomeningeal carcinomatosis hypothesis on the FDG PET/CT exam. Furthermore no focal cerebral lesion was present. Differential diagnosis included CNS infection/inflammation and diffuse malignancy of unknown origin.
Livermore et al : Primary diffuse leptomeningeal atypical teratoid/rhabdoid tumour in an adolescent. Clin Neurol Neurosurg. 2013 Oct;115(10):2170-3
El-Nabbout et al : Primary diffuse cerebral leptomeningeal atypical teratoid rhabdoid tumor: report of the first case. J Neurooncol. 2010 Jul;98(3):431-4
Gauvain et al : Rapidly progressive primary leptomeningeal atypical teratoid/rhabdoid tumor: a report of 2 cases. J Child Neurol. 2012 Dec;27(12):1597-601
Meyers et al : Primary intracranial atypical teratoid/rhabdoid tumors of infancy and childhood: MRI features and patient outcomes. AJNR Am J Neuroradiol. 2006 May;27(5):962-71