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Paper text:
two women in their fifties presented with a bleeding lesion on their nose . at clinical examination , they presented as small pink papules ; one was soft and one was firm on palpation .
polarized dermoscopy revealed a structureless whitish - pink background in both lesions , and an erosion was present in one case ( figure 1a ) . due to the curvature of the face , a handheld reflectance confocal microscope ( vivascope 3000 , caliber i.d . ,
reflectance confocal microscopy ( rcm ) showed a regular epidermal honeycombed pattern with bcc - like structures identified at the dermal - epidermal junction and papillary dermis ( figure 1c ) .
these structures varied in size and shape and had increased cellular density compared to hair follicles .
many had clefting ( dark signal - void region ) around them . in the papillary dermis
, abundant thick collagen bundles were identified mainly around hair follicles ( figure 1c ) .
additionally , numerous small round ( vertical ) to linear and canalicular ( horizontal ) dilated blood vessels were seen ( figure 1c and d ) , as well as small bright round cells ( inflammatory cells ) and angulated bright cells ( figure 1d ) .
facial angiofibromas can sometimes mimic melanocytic nevi or basal cell carcinomas ( bcc ) under clinical and dermoscopic evaluation .
reflectance confocal microscopy is useful in diagnosing melanocytic and non - melanocytic facial lesions   and can be helpful in diagnosing facial angiofibromas that are diagnostically challenging .
favia et al have previously described the ex vivo confocal findings of a gingival angiofibroma in a patient with tuberous sclerosis .
they reported the presence of variably sized vessels with dilated lumina and collagen fibers with random orientation . in our cases
, we found structures mimicking bcc due to increased cellular density and clefting . however , unlike bcc , peripheral palisading ( figure 1e ) was absent . using vertical stacks ( going from the dermis to the epidermis ) we identified continuation between some bcc - like structures and hair follicles .
further , the stroma of angiofibromas lacked typical bcc features such as gossamer collagen , numerous horizontal vessels with leukocyte trafficking , and melanophages ( figure 1f ) .
histologically , angiofibromas are dermal proliferations containing dilated vessels , fibrosis surrounding hair follicles , stellate fibrocytes and distorted hair follicles ( figure 1b ) .
we speculate that the bcc - like structures on rcm represent the base of a rete ridge , a portion of a hair follicle or another adnexal structure that due to the intense perifollicular collagen proliferation could show clefting .
we also identified angulated large bright cells , which appeared smaller than melanophages and could correspond to stellate / spindled fibrocytes .
the density of inflammatory cells ( bright small round cells ) could have been a result of irritation .
a comparison between the rcm and histologic features present in our angiofibroma cases and the bcc features are summarized in table 1 .
facial angiofibromas are benign tumors presenting as firm , dome - shaped , flesh - colored to pink papules , typically on the nose and adjoining central face . clinically and dermoscopically they can mimic melanocytic nevi or basal cell carcinomas ( bcc ) . 
 reflectance confocal microscopy ( rcm ) is a noninvasive imaging tool that is useful in diagnosing melanocytic and non - melanocytic facial lesions . to date 
 no studies have described the rcm features of facial angiofibromas . 
 herein , we present two cases of facial angiofibromas that were imaged with rcm and revealed tumor island - like structures that mimicked bcc , leading to skin biopsy .