Diffuse Large B-cell Lymphoma Arising in the Spleen



Diffuse Large B-cell Lymphoma Arising in the Spleen


Roberto N. Miranda, MD





Key Facts


Terminology



  • Primary DLBCL of spleen is rare


  • Involvement of splenic hilar lymph nodes and bone marrow (usually focal) can occur in primary DLBCL


  • Liver involvement may be part of definition of primary DLBCL of spleen with micronodular or diffuse patterns


  • Patients with history of DLBCL or dissemination at diagnosis are excluded (secondary DLBCL)


Clinical Issues



  • Adults are mainly affected; median age: 64 years


  • 80% 5-year survival for primary DLBCL presenting as distinct mass


Macroscopic Features



  • Solitary or multiple distinct nodular masses surrounded by nonneoplastic spleen


Microscopic Pathology



  • Sheets of large cells with variable cytomorphology


  • B-cell lineage and surface immunoglobulin light chain restriction


Top Differential Diagnoses



  • Diffuse large B-cell lymphoma, systemic


  • Peripheral T-cell lymphoma


  • T-cell/histiocyte-rich large B-cell lymphoma


  • Classical Hodgkin lymphoma


Diagnostic Checklist



  • Single or multiple masses composed of large B cells







Gross photograph shows a multinodular tumor image. Tumor extends into hilar fat image and shows focal infarction image. Well-preserved spleen is dark brown image. Spleen capsule is noted image.






Hematoxylin and eosin shows the most common presentation of DLBCL characterized by a well-circumscribed tumor mass image surrounded by nonneoplastic spleen image.


TERMINOLOGY


Abbreviations



  • Diffuse large B-cell lymphoma (DLBCL)


Synonyms



  • Large cell lymphoma


Definitions



  • Diffuse large B-cell lymphoma that arises in spleen


  • Involvement of splenic hilar lymph nodes and bone marrow (usually focal) can occur in primary DLBCL



    • Liver involvement may be part of definition of splenic DLBCL with micronodular or diffuse patterns


  • Primary DLBCL of spleen can be associated with splenic marginal zone B-cell lymphoma


  • Primary DLBCL of spleen is rare, but represents up to 40% of splenectomy specimens involved by DLBCL


  • Patients with history of lymphoma or evidence of disseminated DLBCL at diagnosis are excluded (secondary DLBCL)


ETIOLOGY/PATHOGENESIS


Infectious Agents



  • No known etiology


  • Primary DLBCL of spleen is rarely associated with hepatitis C or Epstein-Barr virus infection


CLINICAL ISSUES


Epidemiology



  • Age



    • Adults are mainly affected; median age: 64 years



      • M:F ratio approximately 1:1


Presentation



  • Abdominal pain


  • Pain is often left-sided


  • Systemic symptoms such as fever, malaise, and weight loss often occur


  • Fine needle aspiration may yield necrosis only and be wrongly diagnosed as splenic abscess


  • Diagnosis can be suspected in presence of splenomegaly and abdominal or retroperitoneal adenopathy


  • Most patients are immunocompetent



    • Occasionally reported in HIV(+) patients


Treatment



  • Chemotherapy similar to systemic cases of DLBCL



    • R-CHOP is most common chemotherapy used


  • Splenectomy usually performed for diagnostic purposes


Prognosis



  • 80% 5-year survival for patients with primary DLBCL presenting as mass


  • Poor survival for DLBCL with T-cell-rich pattern or neoplasms that diffusely replace spleen



    • These cases often have disseminated disease shown by staging (probably not primary)


MACROSCOPIC FEATURES


General Features



  • Most cases show solitary or multiple distinct nodular masses surrounded by nonneoplastic spleen



    • Neoplasms that diffusely replace red pulp can be subtle grossly


  • Splenic weight can range from normal to > 3,000 g (average: 1,000 g)


  • Tumor size usually ranges from 5-18 cm


  • Multinodular tumor can replace up to 90% of spleen


  • Extensive necrosis is usual


  • Tumor may extend through capsule into adjacent diaphragm, stomach, pancreas, or abdominal wall



MICROSCOPIC PATHOLOGY


Histologic Features



  • Primary splenic DLBCL usually presents as large nodule or mass



    • Nodule/mass typically destroys white and red pulp


    • Approximately 1/3 of cases involve white pulp exclusively or predominantly


    • Approximately 20% of cases involve red pulp predominantly and diffusely


    • Adjacent Malpighian corpuscles may be focally involved


  • Variable cell morphology (centroblastic, immunoblastic, anaplastic, etc.)



    • Relative increased frequency of immunoblastic cases


  • Necrosis within neoplasm is common; sclerosis within or around neoplasm can be observed


  • Surrounding uninvolved spleen is distinctly separated from tumor, sometimes by fibrous bands


Predominant Pattern/Injury Type



  • Lymphoid, diffuse


Predominant Cell/Compartment Type



  • Hematopoietic, lymphoid


Immunophenotype



  • Neoplasms are of B-cell lineage: CD19(+), CD20(+), CD22(+), and pax-5(+)


  • Surface immunoglobulin light chain restriction is detected by flow cytometry in most cases


  • Most cases express Bcl-6 and about 1/3 express CD10


  • CD43 is positive in 20-30% of cases


  • CD3(−), CD5(−), CD23(−/+)


  • Absence of follicular dendritic cells (CD21, CD23) in tumor nodules


Cytogenetic and Molecular Findings



  • Monoclonal IgH rearrangements; TCR genes are usually germline


  • No distinctive cytogenetic or molecular findings


DIFFERENTIAL DIAGNOSIS


Diffuse Large B-cell Lymphoma (DLBCL), Systemic



  • Gross, microscopic, immunophenotypic, and molecular features can be identical to DLBCL arising in spleen


  • Distinction can be made after complete staging


  • Most DLBCL of spleen represent systemic or secondary involvement


T-cell/Histiocyte-rich Large B-cell Lymphoma (TCRLBCL)



  • Subtype of DLBCL that if identified in spleen, is suggestive of disseminated disease


  • Similar to any DLBCL both grossly and microscopically


  • Predominance of small T lymphocytes; large neoplastic B cells represent < 10% of cell infiltrate


  • Recently described micronodular variant (MTCRBL) does not produce large discrete mass but micronodules


  • MTCRBL distributed mainly in white pulp leaving no residual normal white pulp


DLBCL Primarily Involving Red Pulp



  • Unusual variant, clinically aggressive; median age: 69 years


  • Diffuse splenic involvement, predominantly in splenic cords


  • Frequent bone marrow and liver sinusoids infiltration; rare lymph node involvement


  • Mature B cells that usually coexpress CD5; Cyclin-D1 and CD23 negative


Peripheral T-cell Lymphoma (PTCL)



  • May involve white or red pulp


  • Cell composition is more polymorphic than DLBCL with mixture of eosinophils and plasma cells



    • Vascularity is often increased


  • Some cases may have increased histiocytes as well as erythrophagocytosis



  • Neoplastic cells including large cells react with T-cell markers (CD2, CD3, CD5, CD7); usually CD4(+)


Classical Hodgkin Lymphoma



  • Mainly involves white pulp


  • Scattered large Reed-Sternberg and Hodgkin cells in inflammatory background with eosinophils


  • Neoplastic cells are CD15(+), CD30(+), CD45(−), pax-5 (usually dim[+])


Nodular Lymphocyte-predominant Hodgkin Lymphoma (NLPHL)

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Diffuse Large B-cell Lymphoma Arising in the Spleen

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