Rationale:Ganglioneuroma (GN) is a rare tumor that originates from neural crest cells and can manifest in any location along the sympathetic chain. It typically exhibits a circular or oval shape and does not invade the surrounding tissue destructively and the enormous lobular appearance and erosion of adjacent skeletal tissues are extremely infrequent among GN.Patient concerns:A 15-year-old girl presented to our thoracic surgery clinic with a large intrathoracic mass that was incidentally discovered on a chest X-ray. Further imaging with computed tomography and magnetic resonance imaging revealed a lobular profile and an aggressive growth pattern of the tumor, which destroyed the vertebral and rib bones. A tissue sample obtained by needle biopsy was subjected to histopathological analysis, which confirmed the diagnosis of a GN.Diagnosis:Thoracic (posterior mediastinal) GN and Hashimoto’s thyroiditis.Interventions:After thoracoscopic exploration, a thoracotomy was performed to excise the mass.Outcomes:The patient recovered well after surgery, had no major complications, and was discharged without any issues. Further follow-up is necessary to clarify the medium to long-term outcome.Lessons:Based on existing reports, thoracic GN rarely erodes adjacent bone tissue. By examining previously reported cases, we speculate that the lobular morphology of the tumor may be linked to the more aggressive biological behavior of GN. We also discovered that female patients may be more susceptible to bone erosion. However, further research and additional cases are required to confirm these potential associations.