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


METHODS
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.
Hallman
J R
JR
Department of Pathology, Wake Forest University Medical Center, Winston-Salem, North Carolina 27157-1072, USA.
Shaw
J A
JA
Geisinger
K R
KR
Loggie
B W
BW
White
W L
WL
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001707:Biopsy, Needle; D015266:Carcinoma, Merkel Cell / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D017809:Fatal Outcome; D006801:Humans; D007124:Immunoenzyme Techniques; D007382:Intermediate Filaments / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure
D014408:Biomarkers, Tumor