Merkel Cell
Carcinoma
Epidemiology and
Etiology:
·
Common sites:
·
Gross features:
·
Histologic
features:
·
Immunophenotype:
|
Marker: |
Sensitivity: |
Specificity: |
|
CK20 |
|
Negative in
small cell carcinoma of the lung usually |
|
TTF-1 (neg) |
|
Positive in
small cell carcinoma of the lung usually |
|
Synaptophysin |
|
|
|
chromogranin |
|
|
Molecular features:
·
Other features:
·
Adverse prognostic factors:
·
Size > 2cm
·
> 10 mitoses / 10 HPF
·
Extensive lymphatic invasion
·
Extensive vascular invasion
·
Associated Bowen’s disease
·
Divergent squamous differentiation in
invasive tumour
·
Surgical margin positivity
References:
·