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Paper text:
basal cell carcinoma ( bcc ) is a common skin tumor that constitutes 75% of non - melanocytic skin tumors .
more than 80% of bcc cases are localized in areas exposed to the sun , such as the head and neck .
the most important etiological factor is exposure to ultraviolet light , while other risk factors include advanced age , male gender , immunosuppression and arsenic exposure .
bcc can also develop on areas of chronic inflammation , burn scars , squamous cell cancer and ulcers [ 1 , 2 ] .
it is quite rare in areas with no ultraviolet exposure , especially the genital and perianal regions .
a 34-year - old male presented with a bleeding perianal mass that had been growing for the last 6 months .
there was nothing of significance in the personal or family history and especially no history of anogenital warts , sexually transmitted disease , malignancy , inflammatory dermatosis or arsenic exposure .
dermatology examination revealed an exophytic condyloma - like nodular lesion approximately 3  6 cm in size with surface ulceration in the left lateral perianal region and no other pathological findings on whole body examination ( fig .
laboratory test values were normal and the hiv , hsv and syphilis serology results were negative .
histopathological evaluation of a punch biopsy obtained from the lesion showed an edematous stroma containing mononuclear inflammatory cells under a stratified squamous epithelium with epithelial cell islands containing pleomorphic cells and showing infiltrative growth and tumor cell islands with peripheral palisading ( fig .
the tumor cells had a pleomorphic character , with a large vesicular nucleus and narrow cytoplasm ( fig .
histopathological examination of the total excision material was also found to be consistent with superficial bcc .
bcc is seen at a rate of 0.2% among all anorectal cancers and about 1% of all bcc cases are located in the perianal region [ 3 , 4 ] .
a review of the literature reveals that the disorder is more common in males , with a mean age of 73 years .
the etiopathogenesis includes chronic trauma such as itching , chronic dermatitis , nevoid bcc syndrome , p53 mutation , immune deficiency , sexually transmitted disease and arsenic exposure [ 3 , 5 ] .
in contrast to squamous cell carcinoma , perianal bcc cases do not show hpv positivity .
we did not find any other bcc lesions in our patient by whole body examination , and the trigger factors of disease development were not detected .
the differences between the perianal bcc in our patient and those reported in the literature is the early age and lack of known risk factors , indicating that our patient 's disease developed on a background of genetic predisposition via the sonic hedgehog pathway .
the differential diagnosis of perianal bcc includes condyloma acuminatum , bowen 's disease , paget 's disease and squamous cell carcinoma .
it is important to distinguish perianal basaloid ( cloacogenic ) squamous cell tumors because of their aggressive course and early metastatic potential .
the typical palisading appearance and the presence of ber - ep4 monoclonal antibody expression indicate a diagnosis of perianal bcc [ 7 , 8 ] .
patil et al .   emphasized that a lack of tumor retraction artifact and atypical mitotic figures on histopathology as well as the presence of strong ber - ep4 and bcl2 staining on immunohistochemical evaluation indicate bcc .
hpv positivity and p16ink4a upregulation can be present in anal squamous cell carcinomas , but hpv has been shown not to play a role in perianal bcc etiopathogenesis [ 9 , 10 ] .
the bcc diagnosis in our patient was made with the typical histopathological findings and hpv assessment was found to be negative .
the most common perianal bcc type is nodular bcc [ 3 , 8 ] , whereas our patient was diagnosed as superficial bcc .
a literature review revealed that gibson and ahmed   had observed the superficial type as the second most common type at a rate of 18% among perianal and genital region bcc cases , and that patil et al .  
had found one nodular / superficial and one superficial bcc case among the nine perianal bcc lesions that they had evaluated histopathologically .
bcc rarely metastasizes while perianal bcc can have an aggressive course and show more frequent metastasis
. local excision is frequently recommended for bcc treatment , but cryotherapy , radiotherapy , immunotherapy , electrodestruction , photodynamic therapy , immunotherapy , retinoids and chemotherapy are other treatment options when excision is not possible .
we achieved cure with total excision of the lesion in our patient , and new lesion development was not observed during 8 months .
perianal bcc cases are diagnosed later than other types and can be mistakenly treated as inflammatory or infectious lesions .
we also want to emphasize that local excision treatment at the early stage following an accurate diagnosis is effective in ensuring cure without advanced treatments .
basal cell carcinoma ( bcc ) is the most common non - melanoma skin cancer . 
 exposure to ultraviolet light is an important risk factor for bcc development and the disorder therefore develops commonly on body areas that are more exposed to sunlight , such as the face and neck . 
 it is uncommon in the closed area of the body and quite rare in the perianal and genital regions . 
 herein , we report a 34-year - old patient with perianal bcc who had no additional risk factors .