Surgical Pathology Criteria

Dysplasia of the Anus

Differential Diagnosis

Anus high grade squamous intraepithelial lesion (HSIL) Anus reactive atypia
Strong band-like staining for p16 At most patchy or weak staining for p16


Pagetoid Squamous Cell Carcinoma In Situ / HSIL Extramammary Paget Disease
Atypical cells usually merge with surrounding keratinocytes Discrete population of atypical cells
Atypical cells may keratinize Atypical cells may form lumens or be mucin positive
Desmosomes and keratohyaline granules may be visible in atypical cells Desmosomes and keratohyaline granules not present
HMWCK+, p63+, CK7 neg, BerEp4 neg CK7 >90%+, p63 & HMWCK neg (positive if underlying urothelial carcinoma), BerEp4+
GCDFP15 neg GCDFP15 positive if primary, variable if secondary


Anus high grade squamous intraepithelial lesion (HSIL) Bowenoid Papulosis
Usually a solitary enlarging plaque or found within a condyloma acuminatum Multiple small (2-10 mm) plaques
Does not spontaneously regress Lesions come and go spontaneously
Frequently develops invasive carcinoma Infrequent development of invasive carcinoma (may be increased in HIV patients)
Histologically indistinguishable
Both associated with HPV 16
Distinction is made on clinical grounds


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