Lymphomatoid Papulosis



Lymphomatoid Papulosis


Aaron Auerbach, MD, PhD










In this clinical photograph of LyP, there are papules around the buttocks and lower legs at different stages of evolution. (Courtesy R. Willemze, MD.)






Low magnification of LyP type A shows epidermal acanthosis, spongiosis, and a mixed dermal infiltrate containing scattered large, hyperchromatic-staining atypical lymphocytes image.


TERMINOLOGY


Abbreviations



  • Lymphomatoid papulosis (LyP)


Definitions



  • Recurrent, self-healing cutaneous lesions composed of CD30(+) atypical T cells in polymorphous inflammatory background



    • One of the CD30(+) T-cell lymphoproliferative disorders (LyP, primary cutaneous anaplastic large cell lymphoma [C-ALCL], and borderline cases)


ETIOLOGY/PATHOGENESIS


Idiopathic



  • Viral infection, chronic antigenic stimulation, and immunosuppression have all been implicated as factors in some cases


CLINICAL ISSUES


Epidemiology



  • Incidence



    • 0.1-0.2 cases per 100,000


  • Age



    • Mostly adults (30s to 50s), median age 45, less common in children


  • Gender



    • Male:female = 3:1


Site



  • Disease usually confined to skin



    • Common on trunk and extremities


Presentation



  • Multiple erythematous papules or nodules



    • ± ulceration


    • Lesions at different stages of development



      • New lesions simultaneously occur at multiple anatomic sites


      • New lesions develop as old lesions regress


  • May form vesicular, crusted, or hemorrhagic lesions


Natural History



  • Lesions spontaneously heal with scarring



    • Individual skin lesions regress within 3-12 weeks


  • Duration of disease



    • Waxing/waning clinical course; may persist for up to 40 years


  • LyP-associated malignant lymphoma



    • Up to 20% of patients with LyP have another lymphoma



      • LyP may precede, proceed, or occur simultaneously with associated malignant lymphoma


      • Mycosis fungoides (MF), ALCL, Hodgkin lymphoma most common


Treatment



  • Adjuvant therapy



    • No specific treatment for most patients other than follow-up to monitor changes in skin lesions


    • Sometimes low-dose methotrexate ± irradiation and psoralen ultraviolet A


Prognosis



  • Excellent



    • ˜ 100% 5-year survival


  • 2% of associated lymphomas lead to death


MICROSCOPIC PATHOLOGY


Histologic Features



  • Dermal infiltrate, often wedge-shaped or band-like, of medium- to large-sized T cells



    • Sometimes angiocentric


    • Folliculotropic if CD30(+) cells around hair follicles



  • Epidermis may show ulceration, hyperkeratosis, and parakeratosis


  • Variable histology with 4 subtypes (A, B, C, D) representing spectrum of disease



    • Type A (mixed infiltrate)



      • Few scattered large atypical Reed-Sternberg-like or multinucleated cells


      • Abundant reactive polymorphous inflammatory cells


    • Type B (mycosis fungoides-like)



      • Epidermotropism of small T cells showing cerebriform nuclei


      • Only 10% of LyP cases


      • Cannot be separated from MF by histology or immunohistochemistry


      • Type B LyP spontaneously regresses, unlike MF


    • Type C (ALCL-like)



      • Monotonous sheets of large atypical cells


      • Scant polymorphous background infiltrate


      • Cannot be separated from ALCL by histology or immunohistochemistry


    • Type D (cytotoxic T-cell variant)



      • Marked epidermotropism and CD8(+)


  • Polymorphous background infiltrate



    • Histiocytes, neutrophils, eosinophils, and lymphocytes


  • Biopsy may show overlapping features of type A, B, or C


ANCILLARY TESTS


Immunohistochemistry



  • T-cell antigens expressed: CD2(+), CD3(+), CD5(+), CD7(+)



    • ± loss of T-cell antigens (CD7 most common)


  • CD30(+) necessary for diagnosis of type A and type C



    • CD30 often (−) in type B


    • ALK(−), EMA(−)


  • Usually CD4(+), CD8(−), rarely CD8(+) cases (type D)


  • Sometimes (+) for CD15, CD56 (10%), CD25, MUM1, TRAF, and Bcl-2


  • Cytotoxic markers (+) (TIA-1, granzyme-B, perforin)


Cytogenetics



  • No specific abnormalities


In Situ Hybridization



  • t(2;5)(p23;q35) negative

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Lymphomatoid Papulosis
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