A Rare Case of Ruptured Tailgut Cyst Leading to Carcinomatosis

Figure 4

Immunohistochemical stains. The tumor stains weakly positive for CDX2 (a) and CK7 (b). CK7 also highlights the atypical tumor cells colonizing the overlying mucosa (c). CK20 is negative within the tumor but strongly positive in the surrounding unremarkable colonic mucosa (d).

(a)

(b)

(c)

(d)