pilar cysts are common , and benign lesions and malignant transformation in them is extremely rare .
trichilemmal cyst or pilar cyst is defined as a cyst containing keratin and its breakdown products .
it is usually situated on the scalp with a wall resembling external hair root sheath .
it is seen mainly in the at middle age and is inherited in an autosomal dominant fashion . in this case report , we present a 55-year - old man with multiple giant pilar cysts that were present since childhood .
one of the cyst on the chest was transformed to squamous cell carcinoma ( scc ) .
a 55-year - old man was referred to us because of multiple cystic lesions located on the body , some of them measuring several centimeters [ figures 16 ] .
these lesions were present since childhood , and during this period the patient had no complaint except cosmetic concerns .
patient had ignored these lesions for many years until one of the lesions on the chest became ulcerated and then infected [ figure 5 ] .
pathology of the lesion located on the chest showed neoplastic proliferation of the epithelial cells .
pathology of the five other lesions showed a cystic lesion covered with stratified squamous epithelium without granular layer containing homogenous laminated keratin .
mohs surgery was performed to excise large scc of the chest , and the site of operation was repaired by split - thickness skin graft technique .
the patient visited every month for 1 year and during this period he showed no sign of recurrence in the operation site .
also , no change was observed in the remaining pilar cyst of the patient and he is now followed every 6 months .
one of the lesions on the chest was transformed to scc a closer view of the figure 1 close up of lesions on the trunk pilar lesions on the back of patient a close view of the scc showing large infected ulcer pilar cyst of the scalp pathology of the lesion on the chest showing squamous nests in well - differentiated scc pathology of pilar cyst showing trichilemmal pattern of keratinization ( 400 )
pilar or trichilemmal cysts contain keratin and its breakdown products , lined by a wall resembling the external ( outer ) hair root sheath .
the patient had these lesions since childhood , although most patients with this lesions are affected in middle age .
although pilar cyst are usually observed on the scalp , the giant cystic lesions of our lesions were scattered over the whole body .
one of these lesions on the chest was transformed to squamous cell carcinoma that was excised using mohs surgery . according to our literature review , up to now
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
pilar cysts may rarely transform to scc and also may occur on many parts of the body .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
pilar cysts may rarely transform to scc and also may occur on many parts of the body .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
pilar cysts may rarely transform to scc and also may occur on many parts of the body .
 trichilemmal cyst or pilar cyst is defined as a cyst containing keratin and its breakdown products . 
 it is usually situated on the scalp with a wall resembling external hair root sheath . in this case report 
 we present a 55-year - old man with multiple giant pilar cysts that were distributed over the whole body since childhood . 
 one of the cyst on the chest was transformed to squamous cell carcinoma ( scc ) . 
Background
Case Report
Discussion
None
Declaration of patient consent