multiple trichoepithelioma was described by brooke - spiegler in 1892 as epithelioma adenoides cysticum ( brooke 's tumor ) and by fordyce as multiple benign cystic epithelioma . it is an autosomal dominant condition , the gene of which has been mapped onto chromosome 9p21 . we report two cases of multiple trichoepithelioma in a family affecting the mother and her son . she had noticed the first lesion over her left cheek at the age of 9 years . thereafter , the lesions gradually increased in number and size with the increase more evident in the last 10 years . lesions also appeared over the scalp and external ear canals with consequent discomfort in the right ear due to blockage of the auditory canal . a few scattered lesions also appeared over the neck in the course of the last 4 years . her 13-year - old son also developed similar lesions over his face and scalp for 2 years , but they were less in number and size . the mother had multiple skin - colored firm papules and nodules ranging in size from 4  4 mm to 2  3 cm on her face . multiple lesions were seen over the scalp , and both ear canals were almost plugged with the lesions . a few small lesions were present over the neck , and there was a single lesion on her left forearm . examination of her son showed multiple , similar but smaller , and discrete lesions over the face , mainly the central area . histopathological examination of the nodule from mother showed multiple keratinized horn cysts surrounded by basaloid cells and islands of basaloid cells lacking retraction artifact , which was consistent with trichoepithelioma [ figures 13 ] . horn cysts with abrupt and complete keratinized centers surrounded by basophilic cells ( h and e , 10 ) basophilic cells similar to epidermal basal cells and cells in basal cell carcinoma . atypia and mitoses are lacking ( h and e , 40 ) multiple keratinized horn cysts of varying sizes surrounded by basaloid cells along with islands of basaloid cells ( h and e , 4 ) multiple trichoepithelioma or epithelioma adenoides cysticum usually has its onset at puberty as multiple , small , flesh - colored firm papules , nodules , and cystic lesions with a translucent sheen . they are symmetrically arranged on the face , especially in nasolabial fold , but may be located on the scalp , neck , and trunk . large lesions may be yellow or pink or sometimes bluish from pigmentation , and there may be dilated vessels over the surface . individual lesions reach a limiting size , but the number may increase over the years . at times , they may be found in unusual configurations such as a large hemifacial plaque . continued growth or ulceration raises the suspicion of change into basal cell carcinoma , although it is a very rare event . most of the cases reported as such in past are now regarded as the instances of nevoid basal cell carcinoma syndrome . this may be due to the phenotypic dimorphism and variable penetrance of the causative gene on chromosome 9 . multiple trichoepitheliomas have also been rarely associated with a number of systemic conditions such as rombo syndrome which includes vermiculate atrophoderma , milia , hypotrichosis , basal cell carcinoma , and peripheral vasodilation , and also with diseases such as systemic lupus erythematosus and myasthenia gravis . on histological examination , multiple trichoepitheliomas are seen as small , well - circumscribed , symmetric , superficial dermal lesions . the presence of horn cysts is the most characteristic feature with fully keratinized center and surrounding basophilic cells similar to basalioma cells in basal cell carcinoma , except that they tend to lack high - grade atypia and mitoses . the second major component is the basaloid epithelial islands , tightly encircled by fibroblasts , lacking the retraction artifact of basal cell carcinoma . it may present as a solitary smooth nodule on the face of about 0.5 cm size with no risk of malignant transformation . second , it may present later in life as a very large polypoid lesion in the lower trunk , frequently in the perianal area , and is called solitary giant trichoepithelioma . a third presentation mimicking basal cell carcinoma also occur with lesions having a depressed center and a raised rolled edge . it is usually seen on the face and is known as desmoplastic trichoepithelioma or sclerosing epithelial hamartoma . surgery , electrodessication and curettage , x - ray irradiation , dermabrasion , or cryotherapy may all be followed by recurrences or by new lesions . if there is any suspicion of malignant change , adequate excision and histological examination are mandatory .
epithelioma adenoides cysticum or multiple trichoepitheliomas are rare benign hamartomas arising from the hair germ . a 35-year - old female presented with multiple skin - colored firm papules and nodules mainly affecting the central face , scalp , and external ear canal since the age of 9 years . 
 the lesions gradually increased with age . 
 her 13-year - old son also had similar but smaller lesions on the central face . 
 histopathology was consistent with trichoepithelioma .