hair follicle nevus ( hfn ) is a rare hamartoma occurring on the face that shows follicular differentiation . previously , hfn was confused with trichofolliculoma , a benign hamartoma that should be differentiated from hfn . trichofolliculoma can be distinguished from hfn based on the pathological findings of a central cyst - like structure surrounded by a proliferation of hair follicles . the dermoscopic finding of neither a central opening nor a cyst was useful for the differential diagnosis of hfn and trichofolliculoma . we herein report a case of hfn on the nose with sebaceous hyperplasia with characteristic dermoscopic findings . dermoscopy of the lesion demonstrated yellow globules surrounded by crown vessels / telangiectasias and scattered tiny hairs . although there were no previous case reports describing the same dermoscopic findings as in our case , hyperplasia of the sebaceous glands and proliferation of well - differentiated vellus hair follicles were implied by dermoscopy , indicating the diagnostic usefulness of dermoscopy for the cutaneous papular and nodular lesions . the lesion had appeared at 8 years of age and had slightly enlarged before her visit . physical examination revealed a firm , pinkish , dome - shaped papule 4 mm in diameter ( fig . 1 ) . dermoscopy showed yellow globules surrounded by crown vessels / telangiectasias ( fig . although no central follicular opening was observed , tiny hairs were scattered on the lesion . histological examination revealed proliferation of well - differentiated vellus hair follicles in the upper reticular dermis ( fig . interestingly , hyperplasia of the sebaceous glands connected to the hair follicles was also observed . these pathological findings were thought to correspond to the yellowish globules and tiny hairs scattered over the lesion revealed by dermoscopy . the connective tissue sheath of the tiny follicles presented marked fibrous thickening , and the sebaceous glands in the lower dermis were constituted of mature sebocytes ( fig . no central cyst structure surrounded by a proliferation of hair follicles or cartilage was found on histopathological examination . on the basis of these findings pippione et al .   described hfn as a rare hamartoma consisting of well - differentiated vellus hair follicles . until then , hfn had often been misdiagnosed as trichofolliculoma , a benign hamartoma characterized by a central follicular opening with secondary hair follicles . the lesion is flesh - colored to pinkish and sometimes , though rarely , brown . an unusual form of hfn showing pedunculated , skin - colored cutaneous nodule has been reported . the pathological features of hfn include numerous mature vellus hair follicles abnormally located in the upper dermis and occasionally accompanied by sebaceous or eccrine glands and pilar muscles . this case presented a pinkish papule on the nose and histologically small hair follicles vertically aligned in the upper dermis in accordance with the diagnostic criteria for hfn ( fig . in contrast , the hair follicles in the present lesion were immature and very small in comparison with those observed in previous reports of hfn . the progenitor cells in hfn in this case might have preferentially differentiated into sebaceous glands rather than hair follicles . histological as well as dermoscopic examination of the papule revealed no central opening , cyst or hair follicle , thus negating the diagnosis of trichofolliculoma . the hyperplasia of the hair follicles and sebaceous glands suggested the diagnosis of folliculosebaceous cystic hamartoma ; however , this diagnosis was also excluded due to the absence of a central cystic formation . histologically , the absence of cartilage and the anatomical localization of the lesion may negate the diagnosis of accessory auricle . described that the accessory auricle can be differentiated from hfn by the presence of abundant subcutaneous fat . in accordance with this report , proliferation of fat cells was not observed in the lesion presented here ( fig . dermoscopic examination in this case revealed the interesting finding that the yellow globules were surrounded by crown vessels / telangiectasias and that tiny hairs were scattered throughout the lesion ( fig . the dermoscopic findings of juvenile xanthogranuloma include yellow globules against an orange - yellow background . the vessels in juvenile xanthogranuloma are arborizing , whereas those in hfn , often referred to as crown vessels , are non - arborizing and surround yellow nodules . although the yellow globular structures associated with crown vessels were dermoscopically revealed in sebaceous hyperplasia , the color of the globules in the lesion was whitish - yellow . previously the dermoscopic examination of hfn revealed a large number of follicular openings without yellow globules ; however , these findings were not consistent with that of the case described here . although histological examination was required for an accurate diagnosis in the present case , dermoscopy clearly demonstrated the pathological findings , including hyperplasia of the sebaceous glands and proliferation of well - differentiated vellus hair follicles . thus the present case demonstrated the diagnostic availability of dermoscopy for the cutaneous tumor with hair follicular and sebaceous glandular differentiation .
we herein report a case of hair follicle nevus , a rare hamartoma found on the face and showing follicular differentiation , which was associated with sebaceous hyperplasia . 
 dermoscopy of the lesion showed yellow globules surrounded by crown vessels / telangiectasias and scattered tiny hairs . 
 histopathological investigation revealed hyperplasia of the sebaceous glands and proliferation of well - differentiated vellus hair follicles . 
 these pathological findings were thought to correspond to the yellowish globules and tiny hairs observed under dermoscopy . 
 hair follicle nevus associated with sebaceous hyperplasia is extremely rare ; however , dermoscopic examination can suggest an appropriate diagnosis . 
 the present case proved the diagnostic usefulness of dermoscopy for cutaneous tumors with hair follicular and sebaceous glandular differentiation .