Diagnosis and management of retroperitoneal ancient schwannomas

BACKGROUND Ancient schwannomas are degenerate peripheral nerve sheath tumors that very rarely occur in the retroperitoneum. They generally reach large proportions before producing symptoms due to mass effect. We describe three cases of retroperitoneal ancient schwannomas and discuss the diagnosis and management of these tumors. CASE PRESENTATIONS Three female patients with retroperitoneal ancient schwannomas were reviewed. One patient presented with several weeks of upper abdominal pain and lower chest discomfort, whereas back pain and leg pain with associated weakness were predominant symptoms in the remaining two. Abdominal imaging findings demonstrated heterogeneous masses in the retroperitoneum with demarcated margins, concerning for malignancy. The patients successfully had radical excision of their tumors. Histological examination showed encapsulated tumors that displayed alternating areas of dense cellularity and areas of myxoid matrix consistent with a diagnosis of ancient schwannoma. CONCLUSION A diagnosis of ancient schwannoma should be entertained for any heterogeneous, well encapsulated mass in the retroperitoneum. In these cases less radical surgical resection should be considered as malignant transformation of these tumors is extremely rare and recurrence is uncommon following excision.