ultrasound is routinely used to evaluate small breast masses . a large proportion of these small masses
are benign but unfortunately many go to biopsy or excision despite benign imaging characteristics . utilizing our case of adult male pilomatrixoma , we discuss the work - up of small breast masses , focusing on ultrasound characteristics , and stress conservative management if the typical benign sonographic features are present . despite a very low propensity for malignant degeneration ,
surgical excision is the treatment of choice for pilomatrixomas , mainly for symptomatic and cosmetic reasons in a pediatric population .
given the age , location , and low chance of malignant degeneration , conservative management may be considered in rare case of pilomatrixoma of the adult breast .
a 53-year - old male presented with a painless hard palpable  pea - sized  lump , in the right breast , near the nipple .
a referral for mammography was made as the man had a strong family history of breast cancer with two sisters diagnosed at ages 42 and 50 .
diagnostic mammography showed a well - circumscribed , oval - shaped mass of the medial right breast , with smooth borders , and multiple small punctuate calcifications [ figure 1 ] .
gray - scale ultrasound examination revealed a small superficial isoechoic well - marginated oval mass parallel to the skin , with smooth borders , and multiple hyperechoic foci corresponding to calcifications seen on mammogram [ figure 2 ] .
the lesion appeared benign on ultrasound examination , but given the patient 's concern and a strong family history of breast cancer , a core biopsy was performed .
the patient remained anxious about malignancy despite this benign diagnosis , so the mass was excised two months later with an unchanged pathologic diagnosis .
mediolateral oblique view of mammogram demonstrates a small well - circumscribed oval mass just underneath a radiopaque skin marker in the medial right breast near the nipple .
a gray - scale ultrasound image of the lesion shows a well - defined isoechoic oval mass , parallel with the skin measuring 7 mm  3.5 mm , containing the small hyperechoic foci of calcification observed on the mammogram .
pilomatrixoma , originally named  calcifying epithelioma of malherbe ,  was initially described in 1880 by dr .
chenantals malherbe as a calcified epithelioma of sebaceous glands . developing in the subcutaneous tissue and arising from the matrix cells of the hair bulb ,
these benign tumors usually develop during the first two decades of life and have been very rarely described to degenerate to pilomatrixcarcinoma .
the tumors are commonly found on the head with the cheek being a frequent location , followed by the neck and upper extremities in decreasing frequency .
pilomatrixomas are more seldom found on the trunk and lower extremities and are very rarely found in the breast . despite a very low chance for malignant
degeneration surgical excision is the treatment of choice as these tumors do not regress and occur in cosmetically unpleasant locations , usually the head and neck in a pediatric population .
, there have been only five reports of pilomatrixoma of the adult male breast in the english literature .
the tumors were removed in two cases without undergoing medical imaging , most likely due to the size of the tumor .
two other reports described typical benign features of the tumor ; one with mammography and sonography and the other with mammography alone .
sonography is routinely used to evaluate palpable masses as well as incidental masses found on screening mamography . traditionally , ultrasound was used for differentiation of cystic from solid masses but its role has evolved to serve as a guide in characterization of masses into benign , indeterminate , or malignant categories .
the negative predictive value for small breast masses with benign ultrasound features has been quoted to be greater than 99% in several studies.[710 ] features that have been described to most reliably characterize masses as benign are a round or oval shape , circumscribed margins , and width - to - anteroposterior dimension ratio greater than 1.4 .
, if agreed upon by three different readers , these three features predicted benignity with 100% accuracy .
in fact , pilomatrixomas on imaging are commonly well - defined subcutaneous nodules . also , most are heterogeneously hyper- to isoechoic with acoustic shadowing and hyperechoic calcifications , as seen in our case . in general , a differential diagnosis of a superficial breast lesion includes seborrheic keratosis , dermal nevus , epidermal inclusion cyst , and basal cell carcinoma .
although the majority of superficial tumors are benign , management is frequently based on results of the triple test ( physical exam , imaging , and biopsy ) and biopsy is performed despite benign imaging characteristics .
we suggest a conservative approach of interval follow - up for any small superficial breast mass with benign imaging characteristics .
such masses can be assigned into a bi - rads 3 category without a pathologic diagnosis [ figure 4 ] or following a benign biopsy result to ensure stability over time . also , conservative management can be considered in cases of pilomatrixoma of the adult breast .
although , most advise surgical excision of the tumor , especially in a pediatric population , an asymptomatic pilomatrixoma cosmetically acceptable to the patient seems safe to monitor with imaging as there is very low chance of malignant degeneration . given the location and lack of symptoms , conservative management was discussed with our patient but excisional biopsy
was ultimately performed due to anxiety resulting from a strong family history of breast cancer .
a well - circumscribed breast lesion on gray - scale ultrasound parallel to the skin surface has not been biopsied but is likely to be benign given its stability on sonography for nearly two years .
 pilomatrixomas are uncommon benign skin neoplasms arising from the hair follicle matrix . 
 they occur more commonly in children than adults . 
 most originate on the head , neck , or upper extremities , less commonly on the trunk or lower extremities , and very infrequently in the breast . 
 we present a rare case of pilomatrixoma of the breast in an adult male . as the patient had a strong family history of breast cancer , a full work - up of the breast mass 
 was performed . 
 ultimately , an excisional biopsy was carried out for patient reassurance . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION