LAUSR

Plasma cell neoplasms (PCNs) are clonal diseases of terminally differentiated B cells, which secrete a typical monoclonal immunoglobulin called M-protein or paraprotein. They account for approximately 1% of malignant and 10–15% of hematopoietic tumors [1]. PCN can occur as a single lesion (so-called solitary plasmacytoma) or as a multiple lesion (multiple myeloma). Solitary plasmacytomas account for only about 5% of PCNs and present mostly as a single bone lesion (solitary bone plasmacytoma), less commonly as a soft tissue mass (primary extramedullary plasmacytoma (EMP)) [2, 3]. EMPs therefore represent approximately 3% of all PCNs [4]. Almost 80–90% of extramedullary plasmacytomas occur in the head or neck, primarily in the upper respiratory tract. Less than 10% of EMPs affect the gastrointestinal tract (mostly the liver and the stomach) [4, 5]. It is very rare for a plasmacytoma to affect the pancreas: they account for fewer than 0.1% of all pancreatic tumors. Pancreatic involvement is usually the result of a secondary lesion by a known multiple myeloma. In other words, cases of solitary primary pancreatic plasmacytoma are extremely rare worldwide [1]. The first published case of a pancreatic plasmacytoma was in 1947; since then, only 50 cases have been reported in the literature worldwide, most of them as a secondary involvement of the pancreas by a multiple myeloma [1]. Primary extramedullary plasmacytoma mostly affects men (its men to women ratio is 3:1) in the fifth and sixth decades of life. A monoclonal paraprotein is detected in the serum or urine of fewer than 25% of patients. The risk of distant relapse and developing a multiple myeloma is only 30%. The patients’ prognosis is generally very good—statistically, 70% of patients survive 10 years when early treatment is administered [3]. The diagnostic criteria for solitary extramedullary plasmacytoma described by the International Myeloma Working Group in 2009 are 1. no M-protein in serum or/and in urine; 2. extramedullary tumor of clonal plasma cells; 3. normal bone marrow; 4. normal skeletal survey; and 5. no related organ or tissue impairment [6]. Typical clinical signs of a pancreatic plasmacytoma are abdominal pain and obstructive jaundice [7]. The presence of a pancreatic mass, usually in the head of the pancreas, is confirmed by a CT scan or MRI. The CT features are not specific; in a few cases, the tumor has been described as multilobular homogenous solid tumor, hypodense to the pancreatic tissue [4, 12]. Endosonography (EUS) with fine-needle biopsy is currently the method most commonly used to confirm the diagnosis and has very good sensitivity and specificity [15, 16]. On EUS, the reported plasmacytomas usually appear as predominantly hypoechogenic heterogeneous masses [4]. Radiotherapy and surgery are the most common treatment methods. Radiotherapy alone is often chosen in cases of extramedullary plasmacytoma of the head and neck; for EMP in other locations, surgical removal is recommended, * Ján Csomor [email protected]