Basal cell carcinoma, infundibulocystic (ICBCC)

Case 902  3.12.13  (M. Hurt) F 72 scalp 

Difficult lesion causing a lot of debate about the diagnosis, especially with respect to basaloid follicular hamartoma and trichoblastoma.   

ICBCC: From DermnetNZ: This variant shows multiple small cysts containing cornified material with differentiation towards the infundibulum. In distinguishing from trichoepithelioma, it lacks papillary mesenchymal bodies, but frequently retains a mucinous stroma. 

Case 2005  12.2.18  (L. Yu) M 80 eyelid 

Some typical nodules of BCC at edge, but inner cells are pinker.  RC: typical IH in these cases – CD10 (epithelial dominant); CK20 shows trapped Merkel cells; BerEP4 is diffuse and strong apart from keratocysts.  These trichoepithlioma-like BCC’s are usually seen on the central part of the face.  A “TE” on the face in a patient >50 is usually this variant of BCC. 

Case 2075  21.5.18  (L. Yu)  M 65 back 

Lobulated, reticulated basaloid strands (about 70%) vs. 30% stroma.  This form of BCC is much more common in older patients than classical TE.   No papillary mesenchymal bodies here which is against TE.  CD10 is epithelial in BCC, stromal in TE.  CK20 highlights Merkel cells in 30% of TE. 

Case 2638  17.8.20 (IH Chaudhry) F 65 cheek ?BCC 

I and others thought TE, but see 2005 above.  BerEP4 was positive.