Primitive Neuroectodermal Tumor Presenting with Diffuse Leptomeningeal Involvement in a 55-Year-Old Woman: A Case Report and Brief Summary of Current Diagnostic Tests and Treatment

Abstract

Primitive neuroectodermal tumors (PNETs) are typically present as masses in children and adolescents, but rarely in adults. Diagnoses, management strategies, and prognostication factors are not well established in adult cases of PNETs. We describe the case of a central nervous system PNET diagnosed in a 55-year-old woman presenting with a sudden onset of symptoms consisting of increased intracranial pressure and findings of diffuse leptomeningeal enhancement and a small medullary lesion seen on MRI. Amongst the small database of PNETs diagnosed in adults, our case report stands out as one of few cases describing a primarily leptomeningeal PNET diagnosed on biopsy. We also review the literature on PNETs presenting with diffuse leptomeningeal disease and the treatment of PNETs in the adult population.

Malignancy masquerading as chronic meningitis in children

“…The imaging features can often masquerade the leptomeningeal enhancement, basal exudates, or hydrocephalus (secondary to the exudates) due to other infectious or inflammatory causes. [ 4 6 8 ] Tuberculous meningitis is a very common cause of chronic meningitis in our country. The real clinical dilemma occurs when the patient may be deteriorating clinically, and/or a thorough microbiological study is unyielding for a chronic infection such as tuberculosis, slow-growing organisms, fungi, viruses, or parasites.…”

“…The survival rate is poor (often less than 2 years), with greater chances of relapse, and variable response to chemotherapy. [ 4 5 6 7 8 9 ] In the series by Jennings et al ,[ 9 ] diagnosis was made antemortem in a few patients, but largely on a postmortem brain biopsy.…”

“…The red flags to be considered for malignancy are as follows: young age at onset; absence of an underlying source of infection or autoimmune etiology; absence of additional imaging features such as vasculitic infarcts, granulomas, or white matter lesions; worsening clinical picture despite aggressive therapy; absence of response to empirical anti-tubercular therapy with steroids with inconclusive microbiology; and a CSF picture suggestive of lymphocytic predominance with negative cultures for tuberculosis, fungi, viruses, or atypical organisms. [ 3 4 5 6 7 8 9 ] A dedicated CSF for cytology should be performed in every case of chronic meningitis along with tests for infectious or inflammatory causes. A meningeal biopsy, if performed, should include the arachnoid membrane, and the possibility of initial negative biopsies needs to be kept in mind.…”