Anaplastic large cell lymphoma: A potential pitfall in the differential diagnosis of melanoma Academic Article uri icon


MeSH Major

  • Lymphoma, Large-Cell, Anaplastic
  • Melanoma
  • Skin Neoplasms


  • The diagnosis of metastatic melanoma can be complicated by absent characteristic cytology, melanin, or antigen expression in a suspect tumor, putting the pathologist at risk for incorrectly diagnosing recurrent melanoma while missing a second malignancy. We report a 69-year-old man with a history of acral melanoma, metastatic to inguinal nodes, presenting with an ipsilateral thigh nodule. Histology showed a proliferation of pleomorphic cells in the dermis and subcutis, suspicious for melanoma. S100, Melan-A, and HMB-45 immunohistochemistry were negative. However, microphthalmia-associated transcription factor and CD117 labeled the neoplasm, prompting consideration of a late metastatic melanoma with loss of antigen expression. Subsequent immunolabeling for CD4, CD43, and CD30 and clonal T-cell gene rearrangements enabled the correct diagnosis of cutaneous anaplastic large cell lymphoma. This case illustrates a pitfall in evaluating tumors in patients with known metastatic melanoma, and emphasizes the need for broad-spectrum immunohistochemistry in cases that are not clear-cut.

publication date

  • February 2013



  • Academic Article



  • eng

Digital Object Identifier (DOI)

  • 10.5858/arpa.2011-0532-CR

PubMed ID

  • 23368872

Additional Document Info

start page

  • 280

end page

  • 3


  • 137


  • 2