#dermpathJC December 2021 summary

#dermpathJC December 2021 summary

Thursday, December 9th, 9pm EST

Article discussed: Secondary skin involvement in classic Hodgkin lymphoma: Results of an international collaborative cutaneous lymphoma working group study of 25 patients. 

Authors: Gru, A., Bacchi, C. E., Pulitzer, M., Bhagat, G., Kempf, W., Robson, A., Plaza, J. A., Pincus, L., Raghavan, S., Xu, M., Vencato da Silva, T., Salavaggione, A. L., Subtil, A., & Battistella, M. 

Temporary free access courtesy of The Journal of Cutaneous Pathology: https://onlinelibrary.wiley.com/doi/abs/10.1111/cup.14077

Summary prepared by: Suzy Bloomquist, MD (@BloomquistSuzy)

Journal Club Summary:


  • While Hodgkin lymphoma (HL) is a fairly common B cell lymphoma overall in the US (approx. 9000 new cases per year); it is exceedingly RARE in the skin and when present is ALWAYS considered to be a secondary involvement of systemic HL. Simply put, the concept of primary cutaneous HL no longer exists.
  • Many previously reported examples of so-called primary cutaneous HL are now considered to be most likely cases of misdiagnosed lymphomatoid papulomatosis and cutaneous anaplastic large-cell lymphoma which both have overlapping histomorphology and immunophenotypic features with classic HL.
  • Possible mechanisms of skin involvement: “hematogenous dissemination, direct extension from involved lymph nodes, and retrograde lymphatic spread from proximally involved lymph nodes”
  • Implications of skin involvement: usually means the patient has stage IV disease (unless locoregional spread from nearby lymph node)


  • Clinical presentation:
    • In this series:
      • 84% with cutaneous involvement by HL had stage IV disease
      • 67% showed skin lesions involving HL relapse
      • 28% of skin lesions present at time of diagnosis
      • 56% presented with solitary skin nodule (ulcerated lesion in 25%)
  • cd30
  • Histopathology:
    • Mixture of inflammatory cells, spares epidermis
    • Large RS cells may be difficult to find
    • +/- fibrotic bands (nodular sclerosis subtype)
    • Commonly present in the subcutaneous tissue, one case of “panniculitic” involvement
  • Useful IHC:
    • Classic HL: CD30+, CD15+ (usually although some exceptions), PAX-5 weak/dim
      • Negative: CD20 (or weak/focal in few), CD45
      • +/- MUM-1 (non-specific)
      • EBER may be positive
      • CD3+ T cells in background

Differential diagnosis with accompanying immunohistochemistry:

  • In more detail below:
      • Lymphomatoid papulomatosis (LyP):
        • Lacks classic RS cells, PAX-5 (-)
      • Cutaneous anaplastic large cell lymphoma (C-ALCL):
        • Shows dense diffuse infiltrate of the large atypical cells, cells have hallmark appearance, PAX-5 (-)
      • EBV+ mucocutaneous ulcer:
        • Clinical presentation different: around mouth or other mucosal surfaces, patients immunosuppressed and with shallow ulcers
        • NEED history as IHC pattern is very similar
      • EBV+ diffuse large B-cell lymphoma:
        • Cell types: mixture of centroblasts, immunoblasts, pleomorphic cells, RS-like cells, variable lymphocytes and histiocytes
        • Solid sheets of EBV+ cells
        • Strong PAX-5
      • Large B-cell lymphoma, unclassifiable with intermediate features between CHL and diffuse large B-cell lymphoma (gray zone lymphoma):
        • Strong expression of at least one B cell marker (CD20, CD79a, CD15)
      • Post-transplant lymphoproliferative disorders (PTLD):
        • Rarely CHL-like morphology, especially after solid organ transplant
        • Clinical history key

Helpful images:

Figure 1 from paper: Classic HL, nodular sclerosis type – dense dermal lymphocytic infiltrate sparing the epidermis, vague nodular pattern, classic RS cells seen with background mixed inflammatory infiltrate.

Figure 4 from paper: Classic HL, nodular sclerosis type (note nodularity plus bands of fibrosis) IHC staining pattern: note numerous CD3+ T cells in background (neoplastic cells negative). CD30+ (strong, diffuse), PAX-5 is dim in neoplastic cells contrasted to strong staining in background reactive B cells.

Figure 5 from paper: Classic HL, mixed cellularity type. Mixture of cells, no fibrosis, epidermis spared. Note mummified cells. Only rare conventional RS cells.

By popular demand, Dr Cha (@sunpungi) and Dr Gottesman (@SGottesmanMD) prepared a follow up YouTube video Q&A session with Dr Alejandro Gru (@alegru18), available at the embedded video link below:

Memorable tweets:

Hope you enjoyed this #dermpathJC. See you soon!

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