Cytomorphologic features of Merkel cell carcinoma in fine needle aspiration biopsies: A study of two atypical cases

Maj James R. Hallman, Jo Ann Shaw, Kim R. Geisinger, Brian W. Loggie, Wain L. White

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


OBJECTIVE: To report atypical cytomorphologic features in fine needle aspiration biopsies (FNABs) from two cases of Merkel cell carcinoma (MCC), a primary neuroendocrine neoplasm of skin. STUDY DESIGN: Retrospective review of FNABs with histologic correlation from six patients with MCC and a report of findings from two whose smears showed atypical features. RESULTS: Typically the aspirates produce highly cellular smears of loosely clustered and individual, relatively monomorphic, small tumor cells with round to oval, regularly contoured nuclei. In two of our cases, the tumor cell nuclei exhibited a spectrum of pleomorphism ranging from moderately complex nuclear membranes with cleaves, indentations and protrusions in one case to large, markedly bizarre, convoluted nuclei and multinucleate tumor cells in the extreme case. Both cases were primary neoplasms, and the diagnosis was based on clinical, histologic and immunohistochemical data. Additionally, electron microscopy was performed on the tumor with bizarre nuclei and demonstrated rare, dense core neurosecretory granules and paranuclear bundles of intermediate filaments. CONCLUSION: FNAB of MCC may exhibit highly atypical morphologic features that could present difficulty in diagnosis even in patients with a previous history of the neoplasm.

Original languageEnglish (US)
Pages (from-to)185-193
Number of pages9
JournalActa Cytologica
Issue number2
StatePublished - 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine
  • Histology


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