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A 64-year-old man presented with gastrointestinal bleeding and inguinal lymphadenopathy. His lymph node biopsy is presented in slide A. An IgM paraprotein was detected in his serum while a full blood count and film suggested iron deficiency with no lymphocytosis. A small bowel mass was detected on CT scan but the patient declined further investigations including bone marrow studies. He was treated based on the lymph node histology with transient resolution of the bleeding. He subsequently underwent resection of the small bowel mass due to recurrent bleeding. The histology of the small bowel mass is presented in slide B.
Review the high-quality, interactive digital Aperio slide at http://virtualacp.com/JCPCases/jclinpath-2017-204415_A/ and http://virtualacp.com/JCPCases/jclinpath-2017-204415_B/ and consider your diagnosis.
Slide A: What is your diagnosis?
Small lymphocytic lymphoma
Marginal zone lymphoma
Mantle cell lymphoma
Slide B: What is your diagnosis?
Gastrointestinal stromal tumour
Marginal zone lymphoma
The correct answers are after the discussion.
The lymph node shows partial effacement by a diffuse infiltrate of neoplastic, small lymphoid cells with plasmacytic differentiation. Differential diagnoses in the setting of IgM paraproteinaemia include lymphoplasmacytic lymphoma (LPL)/waldenstrom macroglobulinaemia (WM) and marginal zone lymphoma (MZL) with plasmacytic differentiation.1 Immunohistochemistry (IHC) showed light chain-restricted, CD20-positive B cells which were negative for CD5 and cyclin D1 making small lymphocytic lymphoma and mantle cell lymphoma unlikely.1 The MYD88 Leu265Pro mutation is present in 90% of LPL/WM and in <10% of MZL.2 Pyrosequencing of DNA, extracted from the lymph node, confirmed the presence of this mutation.
The patient was treated for LPL/WM and achieved a partial remission (PR) with resolution of the bleeding. Shortly after his sixth cycle of treatment, his bleeding recurred and a CT scan revealed persistence of the ileal mass which was suspected to be the source of bleeding. A small bowel resection was, therefore, performed.
Slide B shows a mesenchymal spindle cell tumour arising from the submucosa.3 Differential diagnoses include gastrointestinal stromal tumour (GIST) and leiomyosarcoma.3 KIT mutations are present in 75% of patients with GISTs and result in overexpression of CD117 which can be detected by IHC.4 CD117 was strongly expressed in this tumour which was helpful to confirm the diagnosis of GIST as leiomyosarcomas are rarely CD117 positive.3
The patient remains in a PR with no bleeding and was offered adjuvant imatinib for the treatment of GIST. Given the distinct pathogenesis of LPL/WM and GIST, we conclude that their simultaneous occurrence was coincidental.
S lide A : C. Lymphoplasmacytic lymphoma
Slide B: A. Gastrointestinal stromal tumour
Take home messages
Lmphoplasmacytic lymphoma (LPL)/waldenstrom macroglobulinaemia (WM) presenting with intestinal involvement is very rare.5
Patients with LPL/WM presenting with intestinal lesions should have endoscopic and histologic evaluation to exclude a concurrent malignancy of gastrointestinal origin.
Metachronous presentation of two biologically distinct tumours is not uncommon and more likely coincidental. Shared aetiological factors or a clonal relationship due to shared genetics may, however, be worth exploring, particularly if the tumours are rare.
Handling editor Iskander Chaudhry.
Contributors SdM conceived of the study and wrote the manuscript. MBA co-wrote the manuscript. K-SP and S-YN performed and provided the pyrosequencing data. SW provided the histopathology images and descriptions. L-MP assisted in the writing and performed a critical review of the manuscript. All authors read and approved the final manuscript.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Commissioned; internally peer reviewed.