Gastrointestinal Plasmacytoma Causing Anemia in a Patient With Multiple Myeloma

Tuba Esfandyari; Susan C Abraham; Amindra S Arora


Nat Clin Pract Gastroenterol Hepatol. 2007;4(2):111-115. 

In This Article

Differential Diagnosis

Anemia occurs in approximately 80% of patients with multiple myeloma. The differential diagnosis of anemia in a patient with multiple myeloma is extensive and multifactorial, and should include diseases that cause gastrointestinal blood loss. Anemia associated with multiple myeloma is usually normocytic and normochromic, and might be related both to the replacement of normal marrow by clonal expansion of tumor cells and to the inhibition of hematopoiesis by factors synthesized and released by the tumor. In addition, mild hemolysis might contribute to the anemia. A fraction of patients might have megaloblastic anemia, owing to either folate or vitamin B12 deficiency. The pathogenesis of the anemia should be established and specific therapy instituted, where possible. Patients with chronic anemia might respond to hematinics (e.g. iron, folate, and cobalamin), and some might respond to androgens. In the setting of renal disease and low serum erythropoietin levels, erythropoietin is useful to increase the red blood cell mass.[1]

The differential diagnosis of gastrointestinal blood loss in a patient with multiple myeloma should include poorly differentiated neoplasms, mucosa-associated lymphoid tissue (MALT) lymphoma and amyloidosis, as well as ulcer-related and unrelated gastrointestinal bleeding disorders, such as peptic ulcer disease, arteriovenous malformation, polyps, or carcinoma. Differentiation from poorly differentiated neoplasms, MALT lymphoma and amyloidosis is very important, as their endoscopic appearance resembles gastrointestinal plasmacytoma, but their management differs both diagnostically and prognostically.[8,9,10] Flow cytometry and immunohistochemistry are helpful in this regard.

MALT lymphomas, now termed extranodal marginal zone B-cell lymphoma, are mainly low-grade B-cell lymphomas, of which 70–80% are confined to the stomach. Up to 80% of gastrointestinal MALT lymphoma tumors regress following eradication of H. pylori.[11] Close follow-up with periodic upper endoscopy and multiple biopsies is recommended for all patients following eradication therapy because of the potential for recurrence.[12]

Gastrointestinal disease in amyloidosis results from either mucosal or neuromuscular infiltration, or an extrinsic autonomic neuropathy, which presents with nausea, vomiting, gastrointestinal bleeding, malabsorption, or (rarely) obstruction.[13] The frequency of gastrointestinal involvement varies with the type of amyloidosis—involvement occurs in up to 60% of patients with secondary amyloidosis, but only 8% of patients with primary amyloidosis.[13] The most common sites of mucosal infiltration in patients with gastrointestinal amyloidosis are the descending duodenum (100%), stomach and colorectum (> 90%), and esophagus (70%).[9] Mucosal infiltration of the gastrointestinal tract by amyloid protein might occur in patients with multiple myeloma and present as bleeding, malabsorption, or even obstruction.[13] The endoscopic appearance of gastrointestinal involvement in patients with multiple myeloma and patients with amyloidosis might be similar.[13]

Cancer in an unknown primary site accounts for 2% of all cancers,[10] and typically presents with symptoms that refer to a metastatic site. The initial work-up, which includes physical examination, and laboratory and radiographic studies, often fails to identify the primary site. If examination of a sufficiently large biopsy specimen does not allow further classification of the neoplasm, additional studies such as immunohistochemical staining, electron microscopy, and chromosomal analysis, should be performed.


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