Skin - Nonmelanocytic tumors
Carcinoma (non-adnexal)
Lymphoepithelioma-like carcinoma (LELC)

Reviewer: Ghassan Tranesh, M.D. (see Reviewers page)
Editor: Hong Qu, M.D.
Editorial Board review: Sara Shalin, M.D.

Revised: 13 October 2016, last major update November 2014

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PubMed Search: Lymphoepithelioma-like carcinoma [title] skin
Cite this page: Lymphoepithelioma-like carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocyticLEL.html. Accessed December 10th, 2016.
Definition / General
  • Exceptionally rare and poorly differentiated cutaneous carcinoma with prominent reactive inflammatory infiltrate
    • Mimics undifferentiated nasopharyngeal carcinoma (Rare Tumors 2013;5:e47)
    • WHO defines these tumors (in nasopharynx/sinonasal cavity) as lymphoepithelial carcinoma
    • Importantly, cutaneous LELC is NOT associated with Epstein Barr virus (EBV) infection
Epidemiology
Sites
  • Head and neck most common site
Pathophysiology
Etiology
  • Uncertain origin (Dermatol Online J 2008;14:12)
  • Unclear whether a poorly / undifferentiated squamous cell carcinoma versus poorly differentiated adnexal neoplasm
Clinical Features
Case Reports
Treatment
  • Wide local excision or Moh's microsurgery to ensure complete removal
  • Radiation reserved for recurrence or lymph node involvement (Case Rep Oncol Med 2012;2012:241816)
  • Generally low recurrence and metastatic potential with complete excision (in contrast to nasopharyngeal counterpart)
  • Rare lymph node metastasis (Am J Dermatopathol 2006;28:211) or death from disease
Clinical Images
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Forehead tumor (pre- and post-excision)

Micro Description
  • With Diagnostic criteria:
    • Well circumscribed lobules, nests or small aggregates of large, cohesive, epithelioid cells closely associated with a dense, mixed T and B lymphocytic and plasmacytic infiltrate (Rare Tumors 2013;5:e47)
      • Biphasic nature may be more apparent at high magnification
    • The epithelioid component generally lacks connection with the epidermis
      • Cells are often polygonal and display poorly defined eosinophilic cytoplasm, vesicular nuclei with prominent nucleoli and increased mitotic activity, including atypical mitotic figures (Dermatol Online J 2008;14:12)
      • Focal ductular differentiation or trichilemmal keratinization rarely reported (J Cutan Pathol 1991;18:93)
    • Mandatory dense inflammatory infiltrate (polymorphous and polytypic) surrounding and intermingling with epithelial tumor cells
      • Lymphoid infiltrate may obscure the epithelial component
      • When inflammation predominates, may mimic lymphoproliferative disorder
Micro Images

Images hosted on PathOut server:

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LELC, courtesy of
Dr. Sara Shalin



Images hosted on other servers:

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Aggregates of atypical epithelial cells

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Vulvar infiltrate with nodal micrometastasis

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No epidermal infiltration



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Atypical, epithelioid cells in syncytial pattern

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Round to polygonal cells with eosinophilic cytoplasm

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Proliferation of epithelial tumor cells and numerous small lymphocytes

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H&E, CK5/6, EBV



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AE1/AE3, EMA

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CD20, CD3

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CK5/6+

Positive Stains
  • CK AE1/AE3 (pancytokeratin), p63, EMA, +/- CK5/6
  • Intraepithelial lymphocytes are typically a mixture of CD20+ B cells and CD3+ T cells with no loss of T cell antigens (i.e. preserved CD2, CD5 and CD7), polytypic plasma cells (both kappa and lambda expressing subsets)
Negative Stains