acanthosis nigricans ( an ) is a skin condition that develops sporadically or in association with obesity , insulin - resistance and dark pigmentary phenotype . in rare cases , both benign and malignancy - associated an present initially as symmetrically dispersed darkened , slightly raised plaques that later progress to thick , keratotic , hyperpigmented , velvety plaques . an may occur at any anatomic site , but the flexural sites of the limbs , armpits and groins , as well as the neck folds are most commonly affected . the workup associated with the diagnosis of an should exclude insulin resistance and internal malignancies ; if an underlying malignancy is found , its treatment may lead to resolution of the an . in idiopathic cases , treatment aims to improve the cosmetic appearance and includes keratolytic creams or laser ablation . although the clinical presentation of an usually points at the correct diagnosis , unusual clinical presentations of an may be diagnostically vexing . herein , we report on two patients presenting with similar hyperpigmented plaques affecting the nipples and discuss the common underlying cause and differential diagnosis . a 20-year - old woman was referred to dermato - oncological surgery because of gradually expanding keratotic plaques on both breasts . the patient presented a fair skin phototype and normal body mass index . her medical and family histories were unremarkable and she denied taking any medications . on clinical examination , symmetrically arranged , diffuse , yellowish to dark brown hyperkeratotic papules and plaques were bilaterally seen on the nipples , areolas and surrounding breast areas ( figure 1 ) . dermoscopy revealed structureless black to yellowish keratotic clods ( figure 1 insert ) . because the lesions were strictly limited to the breasts , the patient was interviewed in detail regarding her hygienic habits and in particular , whether she avoids scrubbing the breast area when taking a shower or drying with a towel ; indeed , the patient confirmed that she avoids direct cleansing of the breasts due to fear and discomfort . subsequently , the patient was given teaching on adequate cleansing methods and was instructed to apply a topical keratolytic cream ( 5% salicylic acid ) for one month . the patient was further offered psychological consultation but declined . at the one - month follow - up visit , the keratotic skin papules and plaques completely disappeared ( figure 2 ) . at subsequent follow - up visits 3 and 6 months later , no recurrence was detected . a 65-year - old man was referred to our skin cancer clinic because of keratotic plaque on the left nipple , tentatively diagnosed by the referring physician as seborrheic keratosis on the nipple . diffuse keratotic , brown to black papules coalescing to plaque were observed on the left areola , and to a lesser extent , also on the right areola ( figure 3a , 3b and 3c ) . dermoscopically , the lesions presented as gray - brown , angulated , keratotic clods ( figure 3d ) . the rest of the skin examination was unremarkable . because of the symmetric arrangement of the keratotic plaques , the patient was asked about his washing routine and confirmed that he avoids washing or scrubbing the nipples because of a feeling of discomfort when touching them . treatment with 5% salicylic acid cream for one month and instruction for methodical washing and scrubbing of the areola areas resulted in complete resolution of the keratotic lesions . at subsequent follow - up visits 3 and 6 months later , there was no recurrence of the keratotic lesions . a 20-year - old woman was referred to dermato - oncological surgery because of gradually expanding keratotic plaques on both breasts . the patient presented a fair skin phototype and normal body mass index . her medical and family histories were unremarkable and she denied taking any medications . on clinical examination , symmetrically arranged , diffuse , yellowish to dark brown hyperkeratotic papules and plaques were bilaterally seen on the nipples , areolas and surrounding breast areas ( figure 1 ) . dermoscopy revealed structureless black to yellowish keratotic clods ( figure 1 insert ) . because the lesions were strictly limited to the breasts , the patient was interviewed in detail regarding her hygienic habits and in particular , whether she avoids scrubbing the breast area when taking a shower or drying with a towel ; indeed , the patient confirmed that she avoids direct cleansing of the breasts due to fear and discomfort . subsequently , the patient was given teaching on adequate cleansing methods and was instructed to apply a topical keratolytic cream ( 5% salicylic acid ) for one month . the patient was further offered psychological consultation but declined . at the one - month follow - up visit , the keratotic skin papules and plaques completely disappeared ( figure 2 ) . at subsequent follow - up visits 3 and 6 months later , no recurrence was detected . a 65-year - old man was referred to our skin cancer clinic because of keratotic plaque on the left nipple , tentatively diagnosed by the referring physician as seborrheic keratosis on the nipple . diffuse keratotic , brown to black papules coalescing to plaque were observed on the left areola , and to a lesser extent , also on the right areola ( figure 3a , 3b and 3c ) . dermoscopically , the lesions presented as gray - brown , angulated , keratotic clods ( figure 3d ) . the rest of the skin examination was unremarkable . because of the symmetric arrangement of the keratotic plaques , the patient was asked about his washing routine and confirmed that he avoids washing or scrubbing the nipples because of a feeling of discomfort when touching them . treatment with 5% salicylic acid cream for one month and instruction for methodical washing and scrubbing of the areola areas resulted in complete resolution of the keratotic lesions . at subsequent follow - up visits 3 and 6 months later , there was no recurrence of the keratotic lesions . hyperkeratosis of the nipple area has been reported in association with a range of diseases including benign and malignant forms of an , atopic dermatitis , darier disease , ichthyosis , hormonal disorders ( diabetes mellitus , insulin resistance and thyroid disease ) , but also after pregnancy or in the context of nevoid hyperkeratosis of the nipple and areola or epidermal nevus . however , the cases presented herein emphasize the importance of anamnestic interrogation , before proceeding to any laboratory workup to exclude conditions that could underlie recent onset an - like plaques . indeed , progressive accumulation of keratotic cellular debris around the nipple due to reluctance to cleanse this area can result in the clinical presentation of new - onset an - like plaques , a process that we refer to as the  neglected nipple . the precise reason for neglecting the nipple hygiene remains to be elucidated , as both of our patients refused psychological consultation ; the avoidance may simply stem from increased local sensitivity to scrubbing or a more complex , psychological process . besides the anamnestic clue , clinical clues to diagnosis of the  neglected nipple  include the presentation of symmetrically arranged hyperkeratotic papules and plaques strictly limited to nipple , areola and surrounding breast region , in the absence of involvement of any of the other body sites classically affected by an . the symmetrical and bilateral breast involvement differentiates the  neglected breast  from pigmented skin neoplasms of the nipple , including melanocytic nevi , melanoma , pigmented paget s disease and seborrheic keratosis ; with few exceptions , the majority of these neoplasms will develop on only one nipple . dermoscopy further aids the exclusion of a tumor , as it reveals exclusively structureless brown - gray - black hyperkeratosis in the absence of criteria associated with melanocytic or non - melanocytic skin neoplasms of the nipple . in the differential diagnosis terra firma - forme dermatosis , wrongly considered a condition arising out of inadequate corporal hygiene , should also be taken into account . it is characterized by occurrence of dirty brown hyperkeratosis on the neck and ankles , suggesting negligence and affects both sexes equally . in conclusion , the  neglected nipples condition , presenting as bilateral an - like papules and plaques of the nipples , is due to avoidance of cleansing of the nipple area , resulting in accumulation of keratotic cellular debris . the diagnosis is confirmed by history and the condition resolved by simple teaching on hygienic methods and transient keratolytic topical treatment . it remains to be further elucidated whether the neglected nipples herald an underlying psychological problem .
background : acanthosis nigricans ( an ) develops sporadically or in association with obesity , insulin - resistance and dark pigmentary phenotype 
 . unusual clinical presentations of an may be diagnostically vexing.objectives:the aim of the report is to present unusual clinical and dermoscopic pictures of hyper - keratotic , brownish lesions of the nipples resembling acanthosis nigricans . 
 patients / methods : data including clinical and dermoscopic features of two patients with the  neglected nipples  : acanthosis nigricans - like ( an - like ) hyperpigmented plaques caused by avoidance of nipple cleansing.results:beside the anamnestic clue , presentation of an - like plaques in the  neglected nipples  is limited to the breasts , in the absence of involvement of other flexural sites classically affected by an . 
 dermoscopy aids the exclusion of a tumor , as it reveals exclusively structureless , brown - gray - black hyperkeratosis in the absence of criteria associated with melanocytic or non - melanocytic skin neoplasms of the nipple . 
 the  neglected breasts  are easily treated by keratolytic creams and hygiene.conclusions:the  neglected nipples 
 condition , presenting as bilateral an - like papules and plaques of the nipples , is due to avoidance of cleansing of the nipple area , resulting in accumulation of keratotic cellular debris .