Anaplastic large cell lymphoma: A potential pitfall in the differential diagnosis of melanoma

Melissa Pulitzer, Mary Sue Brady, Elen Blochin, Bijal Amin, Julie Teruya-Feldstein

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


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 Tcell 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.

Original languageEnglish (US)
Pages (from-to)280-283
Number of pages4
JournalArchives of Pathology and Laboratory Medicine
Issue number2
StatePublished - Feb 2013

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Medical Laboratory Technology


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