Primary spinal pilocytic astrocytoma: clinical study with long-term follow-up in 16 patients and a literature review

Primary pilocytic astrocytoma (PA) of the spine is extremely rare and most published case series only include only a few patients. We attempted to explore the clinical features, radiological findings, and treatment outcomes of patients with spinal PA. Sixteen spinal PA patients who were surgically treated in our hospital between April 2008 and June 2018 were included in this retrospective study. An integrative analysis was performed regarding spinal PA patients by extracting from published studies on PubMed. The 16 patients with spinal PA included eight male and eight female patients with a mean age of 29.1 years. Ten cases (62.5%) had masses located in the cervical segments, five (31.3%) had masses in the thoracic segments, and one (6.2%) had masses in the sacral canal. All the patients were treated surgically with 13 gross total resections (GTRs, 81.3%) and three subtotal resections (STRs). The mean follow-up period was 40.4 months. These tumors accounted for a recurrence rate of 37.5% (6 of 16 patients) and no death during the follow-up periods. The influencing factors of recurrence were mainly STR, gene mutation (NF-1 and H2-K27M), and the number of segments involved. The mean recurrence-free survival duration was 19 months. The imaging features of spinal PA are heterogeneous, and the definitive diagnosis requires pathological support. GTR is the standard therapy for spinal PAs, although patients with GTR are still likely to relapse. The regular spinal magnetic resonance imaging follow-ups are required regardless of the resection status. Reoperation is feasible for patients with recurrence.