Keratoacantomul este o tumora cutanata la limita dintre tumorile benigne si maligne, considerat de multi autori ca un pseudocancer. Diferentierea keratoacantomului de epiteliomul spinocelular intampina greutati cand se folosesc metode histopatologice clasice. Imunohistologia pune la dispozitia cercetatorului metode eficiente de evidentiere a unor markeri celulari capabili sa aduca argumente in diagnosticul diferential.

S-a folosit metoda imunohistologica de punere in evidenta a antigenelor de proliferare nucleara PCNA folosind anticorpi monoclonali aplicati pe sectiuni incluse in parafina dupa o prealabila deparafinare si tratare cu microunde pentru a evidentia epitopii antigenici tisulari.

In keratoacantom reactia imunohistologica de evidentiere a antigenului PCNA a fost pozitiva in special la periferia proliferarilor epiteliale, ceea ce s-a deosebit de dispunerea difuza a aceluiasi marker celular in epitelioame spinocelulare.

Keratoacanthoma is classified by some authors as malignant because its histology resembles a squamous cell carcinoma. Immunohistology provides the investigator with arguments in differential diagnosis because the presence of some cellular markers and their localization can help the distinction between keratoacanthoma and squamous cell carcioma.

We used the imunohistological method for search of the proliferative nuclear antigen PCNA. The paraffin embedded sections were treated after deparaffination with microsound waves for retrieval of the antigenic epitops and then, they were incubated with monoclonal antibodies against the PCNA antigens.

In our material we found a strong expression of the PCNA antigen only in periferal layers of the keratoacanthoma. In squamous cell carcinoma the PCNA antigen was found diffusely.