Journal of Neuro-Oncology 68: 245–248, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. Clinical Study Case report: Pseudomonas aeruginosa-related intervertebral discitis in a young boy with medulloblastoma E. Mazza 1 , F. Spreafico 1 , G. Cefalo 1 , D. Scaramuzza 2 and M. Massimino 1 1 Department of Pediatric, 2 Department of Neuroradiology, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan, Italy Key words: medulloblastoma, Pseudomonas aeruginosa, spondilodiscitis Summary We report a case of a 15-year-old boy with desmoplastic medulloblastoma of the posterior fossa (T3M3, according to Chang classification) incompletely resected, with leptomeningeal and nodular spread in the posterior fossa and in the cervical and thoracic tracts of the spine, treated with sequential high dose iv chemotherapy and with hyperfractionated cranio-spinal radiotherapy. While on maintenance chemotherapy, the boy developed fever and septic status caused by Pseudomonas aeruginosa, and 1 week later also low back pain. Magnetic resonance imaging (MRI) demonstrated abnormal signal in the fourth ventricle and in the dorso-lumbar tract suggesting medulloblastoma recurrence, so he started with a chemotherapy program. Due to a worsening of back pain, a second MRI of the spine was performed that showed a spondilodiscitis of T11-T12 and L1-L2 discs. The histological and cultural examination of a fine-needle biopsy of the L1-L2 disc revealed the presence of P. aeruginosa. So patient was treated with intensive antibiotic therapy with resolution of the infection. Spondilodiscitis is a rare complication in neoplastic patients, maybe due to either immunodeficient status or invasive procedures such as lumbar puncture. This case demonstrates that MRI is a useful method for differentiating between infection and malignancy in the spine, but sometimes it may be difficult to distinguish metastatic tumor from a lesion due to spondilodiscitis. In this case surgicopathological assessment is crucial and mandatory. Spondylodiscitis is a rarely described complication in children with cancer, related to either immuno- deficient status or invasive procedures such as lumbar puncture [1]. We here report our experience with a 15-year-old boy suffering from fourth ventricle desmoplastic medullo- blastoma, liquoral and nodular seeding to cerebellum and to cervico-thoracic spinal cord (Chang stage T3M3). Treatment plan consisted of subtotal resection of the primary tumor, systemic sequential intensive- dose chemotherapy, delayed hyperfractionated- accelerated craniospinal radiotherapy, and a vincristine/lomustine-based maintenance phase. Two months following radiotherapy, while neutropenic due to maintenance chemotherapy, the boy developed a septic status related to Pseudomonas aeruginosa (cultured in blood, both from peripheral venipuncture and central venous catheter, and in urine; no abnormal findings at lumbar puncture), clinically responsive to netilmicin and levofloxacin. Other symptoms/signs were low back pain and paraspinal contracture, slight epatomegaly, 45 ◦ Lasegue, hyposthenia and hypotro- physm at the four limbs. Laboratory tests included neutrophils count 0.6 × 10 9 /l, erythrocyte sedimenta- tion rate 113, quantitative reactive C protein 26 mg/l. Magnetic resonance imaging (MRI) showed slight gadolinium enhancement in the posterior wall of the fourth ventricle and pathological signal in the dorso- lumbar spinal tract. The previous MRI study had been done 1 month before and was normal. A Tc 99 -MDP bone scan, performed at the time pathological MRI was performed, documented a pathologic uptake of the radionuclide at the T11-T12, and L1-L2 vertebrae (Figure 1), interpreted as bone metastasis, while a spinal computed tomography (CT) scan was silent for bony lesions. Due to the neuroimaging findings highly suggesting the medulloblastoma relapse, a second- line chemotherapy was started. One month later,