Lea Roselle O. De Castro, MD, Vincent F. Tatoy, MD, Soriano I. Capaya, Jr., MD, Gracieux Y. Fernando, MD

Malignant Peripheral Nerve Sheath Tumor of the Pancreas: A Case Report and Updated Review of Related Literature

Introduction

Malignant peripheral nerve sheath tumor of the pancreas: a case report and updated review of related literature. Explore the first documented case of Malignant Peripheral Nerve Sheath Tumor (MPNST) of the pancreas in the Philippines. This rare, aggressive sarcoma highlights diagnostic challenges and the need for effective treatments.

Abstract

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas with poor prognosis due to their high recurrence rates. The prevalence of MPNST in the general population is 0.001%, with tumors arising from the retroperitoneum accounting for only 1% of all MPNSTs. In this report, we present a case of a 59-year-old male with pancreatic MPNST. To the authors’ knowledge, this is the first documented case of pancreatic MPNST in the Philippines. The patient initially presented with a 3-month history of abdominal pain, weight loss, and anorexia. On abdominal computed tomography (CT) scan, a large cystic mass involving the pancreatic head and body, with an enhancing peripheral solid component in the superior region was seen. The patient underwent distal pancreatectomy, en bloc splenectomy and excision of duodenal cyst. Post-operative histopathology and immunohistochemistry staining were consistent with pancreatic MPNST with tumor very near the margin of resection adjacent to the portal vein. Adjuvant systemic chemotherapy and radiotherapy were not performed due to lack of evidence of benefit over risk for this population. Disease recurrence (nodal-peritoneal metastases) was noted six months post-operatively and he was given palliative chemotherapy with single-agent doxorubicin. However, disease progression was noted after five cycles of chemotherapy. Second-line regimen was planned but the patient died of a pulmonary embolism prior to the initiation of chemotherapy. Due to the rarity and highly aggressive nature of MPNSTs, furthering knowledge on these tumors is important, particularly in their inclusion among the differential diagnoses for pancreatic tumors. Prompt diagnosis and histopathologic confirmation by a pathologist specializing in sarcomas are crucial in the treatment planning and prognostication of these tumors. Lastly, further studies are needed to establish more effective treatments in unresectable or metastatic disease.

Review

This case report describes an exceedingly rare presentation of a Malignant Peripheral Nerve Sheath Tumor (MPNST) arising in the pancreas, an organ accounting for only 1% of retroperitoneal MPNSTs, themselves occurring with a mere 0.001% prevalence. The authors provide the first documented case of pancreatic MPNST in the Philippines, significantly contributing to the global understanding and geographic epidemiology of this aggressive sarcoma. The report effectively highlights the diagnostic challenges and poor prognosis associated with MPNSTs, particularly when located in such an unusual and critical site. The clinical course of the 59-year-old male patient is well-documented, from initial non-specific symptoms of abdominal pain, weight loss, and anorexia to the definitive diagnosis. The initial imaging finding of a large cystic mass with an enhancing solid component involving the pancreatic head and body provides valuable radiological insight. The patient underwent extensive surgery including distal pancreatectomy and splenectomy, with histopathology and immunohistochemistry confirming pancreatic MPNST. The crucial detail of the tumor being "very near the margin of resection adjacent to the portal vein" underscores the technical difficulty of achieving clear margins in this location and likely contributed to the rapid nodal-peritoneal recurrence within six months. The subsequent failure of palliative chemotherapy further illustrates the highly aggressive nature of MPNSTs and the current lack of effective systemic treatments. This report serves as a critical reminder for clinicians to consider MPNST in the differential diagnosis of pancreatic masses, especially given its aggressive behavior and high recurrence rates. The emphasis on prompt diagnosis and specialized histopathologic confirmation by a sarcoma pathologist is well-placed and essential for optimal patient management and prognostication. While the unfortunate patient outcome highlights the current therapeutic vacuum for unresectable or metastatic MPNST, the authors' call for further studies to establish more effective treatments is timely and imperative. This case report is a valuable addition to the literature, expanding our knowledge of this rare and deadly disease.

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