Unicentric Hyaline Vascular Variant Castleman Disease



Unicentric Hyaline Vascular Variant Castleman Disease


Pei Lin, MD





Key Facts


Clinical Issues



  • Young adults


  • Lymphadenopathy, localized


  • Excision is usually curative


Microscopic Pathology



  • Large follicles with regressed (involuted) germinal centers


  • 2 or more germinal centers per follicle (“twinning”)


  • Concentric rings of mantle zone lymphocytes (“onion skin”)


  • Hyaline-vascular (“lollipop”) follicles


  • Increased vascular proliferation in interfollicular zones


  • Plasma cells and immunoblasts are not abundant


Ancillary Tests



  • Polytypic B cells and normal T cells


  • Increased FDCs in germinal centers: CD21(+), CD23(+), CD35(+), &/or EGFR(+)


  • No evidence of monoclonal Ig or TCR gene rearrangements


  • No consistent cytogenetic or molecular abnormalities known


Top Differential Diagnoses



  • Castleman disease, plasma cell variant


  • Thymoma


  • Angioimmunoblastic T-cell lymphoma


  • HIV lymphadenitis


  • Castleman-like changes associated with various lymphomas







Castleman disease, hyaline-vascular variant (HV-CD). Regressed germinal centers image are surrounded by expanded mantle zones image. There is also marked interfollicular blood vessel proliferation image.






Positive CT scan shows a 4.5 cm mass in the low left paraspinal region image. The site of disease in this patient is unusual but is otherwise consistent with unifocal HV-CD.


TERMINOLOGY


Abbreviations



  • Castleman disease, hyaline-vascular variant (HV-CD)


Synonyms



  • Angiofollicular lymph node hyperplasia


  • Giant lymph node hyperplasia


  • Angiomatous lymphoid hamartoma


Definitions



  • Typically unicentric and reactive lymphoproliferation of unknown etiology involving lymph nodes


ETIOLOGY/PATHOGENESIS


Unknown



  • Possible factors in pathogenesis



    • Dysregulation of vascular endothelial growth factor


    • Follicular dendritic cell (FDC) dysplasia may be precursor


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare


  • Age



    • Young adults; median age: 4th decade


  • Gender



    • No preference


Presentation



  • Patients present with localized mass



    • Mass often detected incidentally


  • Rarely symptoms related to compression of adjacent tissues by enlarged lymph nodes


  • Lymphadenopathy, localized



    • Mediastinal or thoracic lymph nodes most commonly involved


    • Other sites: Cervical and retroperitoneal lymph nodes


    • Extranodal sites of involvement are rare


  • Patients may develop secondary amyloidosis


Treatment



  • Surgical approaches



    • Surgery to remove enlarged lymph nodes


  • Adjuvant therapy



    • Usually not necessary


    • Radiation therapy has been used to alleviate compression symptoms


Prognosis



  • Excellent


  • Surgical removal is usually curative; relapse can occur uncommonly


  • Malignant neoplasms can arise in association with HV-CD



    • Follicular dendritic cell sarcomas are most common


    • Vascular neoplasms


    • Secondary neoplasms in HV-CD are often low grade but metastases are reported


IMAGE FINDINGS


Radiographic Findings



  • Enlarged lymph node or group of lymph nodes, but any site can be involved



    • Mediastinal or thoracic lymph nodes most common


MICROSCOPIC PATHOLOGY


Histologic Features



  • Numerous follicles in cortex and medulla of lymph node


  • Obliteration of subcapsular sinuses



  • 2 or more germinal centers in a follicle (“twinning”)


  • Follicles typically large with regressed (or involuted) germinal centers



    • Germinal centers are composed mostly of FDC with few lymphocytes


    • FDCs often hyperplastic and can show dysplasia


  • Many follicles show so-called “lollipop” features characterized by



    • Concentric rings of the mantle zone lymphocytes (“onion skin” appearance)


    • Sclerotic blood vessels radially traversing into germinal center


  • Interfollicular or stromal component is also important



    • Increased number of high endothelial venules with hyalinized walls


    • Stromal component can predominate with only few hyaline-vascular follicles


  • Clusters of plasmacytoid dendritic cells (plasmacytoid monocytes) can be prominent


  • Plasma cells and immunoblasts are not abundant in HV-CD



    • Much more common in plasma cell variant of CD


ANCILLARY TESTS


Immunohistochemistry



  • Human herpes virus-8 (HHV8) is absent


  • Polytypic B cells and T cells


  • Increased FDCs in involuted germinal centers often positive for CD21, CD23, CD35, or EGFR



    • Dysplastic FDCs often stain variably for FDC markers


  • Plasma cells are polytypic


Flow Cytometry



  • Polytypic B cells and T cells with normal immunophenotype


Cytogenetics



  • Rare cases reported with chromosomal translocations or other clonal abnormalities



    • No consistent cytogenetic findings


  • Del(12q13-15) resulted in intragenic HMGIC gene rearrangement reported in 1 case


PCR



  • No evidence of monoclonal immunoglobulin (Ig) or Tcell receptor (TCR) gene rearrangements

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Unicentric Hyaline Vascular Variant Castleman Disease

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