Cutaneous Marginal Zone B-cell Lymphoma



Cutaneous Marginal Zone B-cell Lymphoma


Aaron Auerbach, MD, PhD





Key Facts


Terminology



  • Non-Hodgkin small B-cell lymphoma of centrocytelike marginal zone cells


  • Malignant B cells expanding marginal zones surrounding reactive follicles and colonizing them


Etiology/Pathogenesis



  • Borrelia burgdorferi in some cases


  • Associated with autoimmune disease


Clinical Issues



  • Excellent prognosis; 5-year survival: 90-100%


  • Usually treated with excision or radiation


Microscopic Pathology



  • Small B cells, monocytoid, plasmacytoid


  • Colonized germinal centers


  • Lymphoepithelial lesions rare


  • ± Dutcher bodies


Ancillary Tests



  • B cells positive for CD20, may coexpress CD43 and Bcl-2


  • Germinal centers Bcl-6(+), CD10(+), Bcl-2(-)


  • CD21(+) loose follicular dendric cell meshworks


  • Usually light chain restriction and clonally rearranged immunoglobulin genes


  • t(11;18) negative


Top Differential Diagnoses



  • Follicular hyperplasia


  • Primary cutaneous follicle center lymphoma


  • Plasmacytoma


  • Secondary involvement by systemic marginal zone lymphoma







Low magnification of a primary cutaneous MZL shows a prominent, diffuse dermal lymphoid infiltrate, which infiltrates between collagen bundles image and is separated from the epidermis by a grenz zone image.






This is another case of cutaneous marginal zone B-cell lymphoma that is extending into the subcutaneous tissue with a nodular and diffuse growth pattern.


TERMINOLOGY


Abbreviations



  • Primary cutaneous marginal zone lymphoma (PCMZL)


Synonyms



  • Primary cutaneous immunocytoma


Definitions



  • Non-Hodgkin small B-cell lymphoma of centrocyte-like marginal zone cells



    • Recapitulates architecture of Peyer patches



      • Usually in sites without significant lymphoid tissue


    • Malignant B cells expanding marginal zones surrounding reactive follicles and colonizing them


  • May be difficult to diagnose because of nonspecificity of many of the morphologic features, absence of 1 or more classic features, and nature of the small biopsies


ETIOLOGY/PATHOGENESIS


Infectious Agents



  • Borrelia burgdorferi DNA found in skin in some European cases, but not in other populations



    • Other infectious diseases noted in tissue other than skin



      • Helicobacter pylori implicated in gastric marginal zone lymphoma


      • Campylobacter jejuni implicated in small intestine marginal zone lymphoma


      • Chlamydia psittaci implicated in ocular marginal zone lymphoma


Autoimmune Diseases



  • Marginal zone lymphoma has been associated with patients who have autoimmune diseases



    • Sjögren syndrome and parotid gland marginal zone lymphoma


    • Hashimoto thyroiditis and thyroid marginal zone lymphoma


CLINICAL ISSUES


Epidemiology



  • Age



    • Usually adults > 40 years old


  • Gender



    • No gender predominance


  • Ethnicity



    • No ethnic propensity


Site



  • Mostly upper extremity



    • Also head and neck and torso


Presentation



  • 1 or more plaques or nodules



    • Rarely ulcerates


    • Multiple nodules often seen in systemic marginal zone lymphoma with secondary spread to dermis


Treatment



  • Excision or radiation therapy



    • If solitary or only a few lesions



      • Chemotherapy only considered for widespread disease, metastasis


  • Antibiotics



    • Sometimes therapy for Borrelia burgdorferi infection


Prognosis



  • Excellent



    • 5-year survival: 90-100%


    • But tendency to recur



      • Rarely transforms to large B-cell lymphoma


      • So look for sheets of large B cells for diagnosis of large B-cell lymphoma


      • Scattered large B cells are often seen in PCMZL



MACROSCOPIC FEATURES


General Features



  • 1 or more firm red nodules on skin


MICROSCOPIC PATHOLOGY


Histologic Features



  • Nodular to diffuse dermal infiltrate



    • Spares epidermis with grenz zone


    • Sometimes involves subcutis


    • Malignant B cells expanding marginal zones surrounding reactive follicles and colonizing them


  • Lymphoepithelial lesions (very rare in skin)


  • Neoplastic cells



    • Sometimes monocytoid with ample pale/clear cytoplasm


    • Sometimes plasmacytoid with eccentric nucleus and pink cytoplasm


    • Variable numbers of plasma cells, neutrophils, and eosinophils


    • Mostly small in size with coarse chromatin and mild atypia


  • Dutcher bodies (intranuclear inclusions)



    • Sometimes seen


    • More often in marginal zone lymphoma than plasmacytoma


    • Russell bodies are cytoplasmic inclusions that may also be seen, but are less specific


  • Reactive germinal centers



    • Colonized by neoplastic marginal zone B cells


    • Still contain tingible body macrophages


    • Retain mantle zones



      • If tissue is small, may not see follicles


  • Follicular dendric cell meshworks



    • Often disrupted/loosened in colonized germinal centers


  • Lymphoepithelial lesions



    • 3 or more lymphocytes entering epithelial structure (usually a gland) and destroying it


    • Very rarely seen in skin


Cytologic Features



  • Small to medium-sized B cells with mild atypia, 1 or more inconspicuous nucleoli, and scant pale cytoplasm


ANCILLARY TESTS


Immunohistochemistry

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Cutaneous Marginal Zone B-cell Lymphoma

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