Fine-needle aspiration biopsy of the central nervous system performed freehand under computed tomography guidance without stereotactic instrumentation.

BACKGROUND: Biopsy of the central nervous system (CNS) has been reported previously using relatively large-caliber (12-17-gauge) biopsy instruments with or without stereotactic guidance. In this series, fine-needle aspiration biopsies (FNABs) were performed using a smaller diameter needle to evaluate mass lesions of the CNS. METHODS: One hundred thirty FNABs were performed freehand under computed tomography (CT) guidance without stereotactic instrumentation guidance using a 22-gauge needle. RESULTS: A definitive diagnosis was rendered in 97 of 130 FNABs (75%), including glioblastoma multiforme (GBM) (n = 33 biopsies); anaplastic astrocytoma (n = 14 biopsies); metastatic carcinoma (n = 13 biopsies); low-grade astrocytoma (LGA) (n = 10 biopsies); lymphoma (n = 7 biopsies); oligodendroglioma (n = 5 biopsies); reactive gliosis (n = 2 biopsies); and abscess (n = 13 biopsies), with the infectious agent identified in 7 of 13 biopsies. Immunohistochemistry was employed in 51 biopsies to assist in determining either the cell type or the infectious agent. Indefinite diagnoses were rendered in 33 patients (25%), including LGA versus gliosis (n = 8 patients), necrosis and/or inflammation (n = 3 patients), nondiagnostic material (n = 17 patients), suspicious for lymphoma (n = 2 patients), suspicious for GBM (n = 2 patients), and high-grade neoplasm not otherwise classified (n = 1 patient). There was no morbidity or mortality attributed to the procedure. CONCLUSIONS: FNAB of CNS mass lesions established a diagnosis based on cytologic interpretation in 75% of biopsies without morbidity or mortality. Because morbidity and mortality rates in CT-guided biopsies utilizing stereotactic techniques with large-caliber needles have been reported as high as 14% and 4.7%, respectively, freehand FNAB under CT guidance may be a preferred initial method for evaluating mass lesions of the CNS.

Ventral polyradiculopathy with pediatric acute lymphocytic leukemia.

A 3-year-old girl with acute lymphocytic leukemia (ALL) in remission developed lower extremity paraparesis and areflexia 15 days after receiving intrathecal methotrexate, cytarabine, and hydrocortisone. Cerebrospinal fluid protein was 107 mg/dl. Compound muscle action potential amplitudes were reduced, F waves were absent, and sensory conduction studies were normal. Needle electromyography (EMG) revealed reduced motor unit potential recruitment. Magnetic resonance imaging (MRI) showed lumbosacral ventral root enhancement. She was treated with intravenous immunoglobulin and slowly recovered. Nerve conduction and EMG abnormalities correlated with MRI root enhancement, facilitated early diagnosis, and distinguished this from a myelopathy or distal polyneuropathy. These findings could represent selective ventral nerve root vulnerability to intrathecal chemotherapy. A selective autoimmune process cannot be excluded.