Schwannoma: a spectrum from benign to malignant

Peripheral nerve sheath tumors are a group of neoplasms that arise from Schwann cells. This study evaluates the histopathological and immunohistochemical (IHC) characteristics of these entities, spanning a spectrum from benign to malignant lesions. We focused on tumor variants, particularities, and differential diagnoses. A total of 25 cases were analyzed, with conventional schwannomas being the most common benign tumor subtype. Classic schwannomas exhibited typical Antoni A and Antoni B patterns, with Verocay bodies as defining features. Additionally, less common variants, such as cystic and myxoid schwannomas, were identified, highlighting the morphological variations of these entities. Malignant peripheral nerve sheath tumors (MPNSTs), representing the malignant counterpart, were characterized by spindle cell and epithelioid morphologies, high mitotic activity, and aggressive clinical behavior. Differentiating MPNSTs from other soft tissue tumors, such as neurofibromas and melanomas, was challenging due to overlapping histological features. IHC markers, particularly S100 and sex determining region Y (SRY)-box transcription factor 10 (SOX10), played an important role in the diagnostic process, though their interpretation required precision to avoid diagnostic pitfalls. This study highlights the importance of integrating histopathology and immunohistochemistry for accurate diagnosis and differentiation of peripheral nerve sheath tumors. The recognition of rare variants and analysis of tumor subtypes contribute to a better understanding of these entities, which is crucial for appropriate clinical management.