This cluster of cells, one of few, derived from plaques and nodules in parietal pleura of a 62 yo male.
In situ scrapping of pleural biopsy stained with Methylen blue 1%.
Diagnostic considerations: malignant, non small cell tumor. Difficult subtyping. Some lumen or cytoplasmic vacuolization could be suspected. Nucleoli are ready aparent.
My first impression was of an Adenocarcinoma. Mesothelial origin could not be ruled out.
In permanent sections a poorly diferentiated carcinoma was observed, with isolated microlumen present and some vacuolated cells. However extensive eosinophilic cytoplasm was present.
In IHC slides P63 was strongly positive. Calretinin, CK7, TTF-1 and Napsin A negative.
Without other available antibodies (ie GATA 3, etc) a diagnosis of secondary SCC or Urothelial carcinoma was rendered.