Diagnosing Gastric Plasmacytoma

Extramedullary plasmacytomas are rare ( > 5% of all plasma cell neoplasms), and the gastric version is even more rare. That rarity combined with unspecific symptoms that mimic other tumors “can mislead the clinician into a diagnosis of a more aggressive tumor,” say clinicians from University Hospital Center of Coimbra in Portugal. They reported on a patient who presented that diagnostic puzzle.

The patient arrived in the emergency department with symptoms of upper gastrointestinal bleeding. He had a history of tongue carcinoma, cirrhosis, diabetes mellitus, chronic gastritis, and obesity, among other health conditions, and was taking a panoply of medications. The patient’s family history included a grandmother with breast cancer and an aunt with head and neck cancer.

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The clinicians embarked on an extensive diagnostic process of elimination. Endoscopy, immunohistochemistry, and other tests helped rule out Helicobacter pylori infection, lymphoma, carcinoma, melanoma, and neuroendocrine carcinoma. “Rethinking our possibilities,” the clinicians say, and taking into account the presence of mature and immature plasmocytes in the periphery, they next considered plasmacytoma/multiple myeloma (MM). On the third immunohistochemical panel, they got the evidence they needed for the diagnosis: gastric plasmacytoma (GP)/ involvement by MM.

Gastric plasmacytomas have a good prognosis. Surgical excision normally is the treatment of choice with good results, the clinicians say. After endoscopic polypectomy without radiation, the patient was discharged with no further therapy. Although diagnosed with prostate cancer in the 6 years following, the patient has had no signs of plasmacytic relapse.

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Due to their cellular similarity, GP needs to be differentiated from MM. But GP may be the initial manifestation of a MM, the clinicians note. Therefore, the patient must undergo systemic evaluation to exclude bone marrow involvement and to make sure there is no clinical or laboratory evidence of myeloma.

Sources:

1. Oliveira RC, Amaro P, Julião MJ, Cipriano MA. BMJ Case Rep. 2017. pii: bcr2016218967.
doi: 10.1136/bcr-2016-218967.

2. International Myeloma Working Group. Br J Haematol. 2003;12(5):749-57.
doi: 10.1046/j.1365-2141.2003.04355.x

3. Kilciksiz S, Karakoyun-Celik O, Agaoglu FY, Haydaroglu A. A review for solitary

plasmacytoma of bone and extramedullary plasmacytoma. Sci World J. 2012;2012:895765.
doi: 10.1100/2012/895765.