Clinical: multiple papules in anogenital region of young men that histologically resemble squamous cell carcinoma in situ.
Most often related to HPV 16.
Usually transmitted sexually.
Younger patients than PEIN (30's to 40's).
Gross: usually occur on penile shaft; papules range from 0.2 to 1.0 cm; sometimes coalesce to form plaques like condyloma acuminatum.
Proliferation of atypical basaloid cells and koilocytic change can be seen (image A) & (image B). (Resemble HPV-related PEIN).
May involve sweat gland (unlike PEIN).
Usually spare the pilosebaceous units (unlike PEIN).
Most have benign course and may undergo spontaneous regression.
Minority may progress to SCC; but mainly considered not precancerous.