Secondary Pancreatic Diffuse Large B-Cell Lymphoma: A EUS Diagnosis of a Rare Cause of Pancreatic Mass

Germana de Nucci, Nicola Imper


Context Pancreatic lymphoma is a rare cause of pancreatic mass, accounting for 0.5% of all pancreatic neoplasms, frequently misdiagnosed as epithelial cancer thus leading to incorrect therapeutic management. In the last few years Endoscopic Ultrasound has emerged as the most cost-effective and safe procedure and it is now recognized as the first-line procedure in the management of solid and cystic pancreatic masses. However, endoscopic ultrasound -guided fine needle aspiration diagnosis of pancreatic lymphoma remains challenging for both endoscopists and pathologists. Case report Here we present an unusual case of secondary, pancreatic, nodular involvement in a patient who suffered from a diffuse large B-cell lymphoma 3 years earlier. To better characterize this radiological finding, an endoscopic ultrasound was performed, which showed in the uncinated process of the pancreas a hypoechoic mass measuring 17 mm in diameter. A fine needle aspiration was performed in order to rule out pancreatic involvement by the known lymphomatous disease. Both the direct smears and the cellblock sections displayed an abundant, scattered population composed by monomorphous large cells with round nuclei, with multiple nucleoli acting as lymphoid centroblasts. The immunocytochemistry analysis confirmed the cytological hypothesis showing expression of CD20 and CD79a and negativity for CD3 and cytokeratin AE1/AE3. Finally, a diagnosis of pancreatic B-cell lymphoma was achieved. Conclusion pancreatic malignant lymphomas are unusual, solid tumors categorized as nonepithelial neoplasms. Endoscopic ultrasound - fine needle aspiration appears a safe, useful and valuable diagnostic modality for diagnosing pancreatic lymphoma. Moreover an important role is played by the pathologist's expertise to achieve an accurate diagnosis.

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