acanthosis nigricans ( an ) is a cutaneous eruption characterised by symmetric velvety hyperpigmented , verrucous plaques of the intertriginous surfaces of the axilla , neck , inframammary , and mucocutaneous regions and can be classified as benign or malignant .
benign cases are typically associated with obesity and insulin resistance , while malignant an ( man ) has been associated with intra - abdominal malignancies including gastric , oeseophageal , pancreatic , and hepatic duct adenocarcinomas and also rarely gynaecological malignancies .
we present the case of a 28-year - old female with an associated with a combination of benign and malignant aetiologies .
she initially presented with benign features of obesity and insulin resistance ; however , the progressive nature of her an later manifested as a paraneoplastic dermatosis of endometrial adenocarcinoma .
a 28-year - old morbidly obese female was referred to the dermatology clinic with a pruritic , hyperpigmented facial eruption .
the patient reported this profound increase in pigmentation occurred after she gained approximately 3040 kg over the last 8 years since the birth of her first child .
she had been using intermittent topical corticosteroids for the last 5 years with minimal effect .
she had been feeling otherwise well with no constitutional symptoms and denied any alteration in her bowel habit , melaena , or per rectal blood loss .
her background medical issues included morbid obesity , sleep apnoea , and a recent diagnosis of bilateral cataracts , requiring surgery .
she reported a positive family history of diabetes and breast cancer but denied any personal history of diabetes or malignancy .
she was currently unemployed and lived with her 7-year - old daughter . on examination , the patient was obese with a bmi of 49 .
there was widespread hyperpigmentation with marked skin thickening of her axillae , arms , abdominal folds , face , and ears ( fig . 1 , fig .
she had macrocephaly with a prominent nose , round face and a  buffalo hump  .
examination of the scalp revealed cerebriform folding of the skin consistent with cutis verticis gyrata .
multiple punch biopsies were performed which showed psoriasiform hyperplasia , moderate dermal fibrosis , and superficial to mid - perivascular and perifollicular inflammation consistent with an . given the extensive presentation of an , the patient subsequently underwent extensive investigations for potential endocrinopathies and to exclude underlying malignancy .
serological investigation showed a mild polycythaemia with a haemoglobin level of 163 g / l , with an otherwise normal full blood count and iron studies .
she had an elevated alt of 49 u / l , but other liver function tests were normal .
mmol / l , and triglycerides were 2.1 mmol / l . in terms of investigation for endocrinopathy , she had an undetectable growth hormone , a low igf-1 at 7
nmol / l , a low 24-h urinary free cortisol and normal thyroid function tests .
fsh and lh were significantly depressed , and she had elevated testosterone and free androgen index . the patient was referred to gynaecology where she underwent a further panel of investigations .
a ct of the chest , abdomen , and pelvis revealed no abnormalities , and tumour markers were also unremarkable , with a nonsignificant ca 125 level of 16
histology of the curettings confirmed grade 1 adenocarcinoma of the endometrium , and the patient was scheduled for a formal hysteroscopy / dilation and curettage in 3 months time . additionally , the patient was referred to dietetics for education regarding diet and weight reduction and was referred for a formal sleep study to investigate her sleep apnoea .
an is a cutaneous eruption characterised by symmetric velvety hyperpigmented , verrucous plaques of the intertriginous surfaces of the axilla , neck , inframammary , and mucocutaneous regions .
an is a cutaneous marker of systemic diseases , which can be classified into benign and malignant forms .
benign an can be familial , drug induced , or correlated with a variety of endocrinopathies , notably insulin resistance and obesity .
in contrast , man is most commonly related with intra - abdominal malignancies and very rarely gynecological carcinomas .
man is usually rapid in onset , widespread in distribution , and sometimes has facial involvement .
it can also be associated with skin tags , multiple seborrheic keratosis ( the sign of leser - trelat ) , or ridged velvety lesions on the palms ( tripe palms ) .
the pathophysiology of an is unknown but thought to involve one or more stimulating factors , which ultimately cause the epidermal proliferation that is seen on histopathological section . in man ,
the proposed etiology is thought to involve tumour secretion of a peptide with growth factor properties  potentially transforming growth factor - alpha , insulin growth factor-1 , or melanocyte - stimulating hormone alpha .
histopathology of biopsies typically reveals papillomatosis , hyperkeratosis , and acanthosis and an increased number of basal melanocytes .
interestingly , man tends to follow the course of an underlying malignancy  often spreading with tumour progression , then regressing with successful therapy .
gynaecological malignancies have rarely been reported with man including 6 cases of ovarian cancer , 5 cases of endometrial carcinoma , and 2 cases of cervical carcinoma ( table 1 ) .
these patients presented with man between the ages of 4783 years , with an average age of 59.5 years .
tripe palms and man occurring in the axillae are the most common sites occurring in 77 and 85% of the cases , respectively . compared to previous cases , our case is of particular interest because our patient 's an could be due to a combination of both benign and malignant aetiologies  which has not previously been reported .
the patient initially had features consistent with a benign form including an insidious onset at a young age associated with insulin resistance and obesity .
this was then followed recently with a rapid year - long deterioration of the condition associated with widespread hyperpigmentation and hyperkeratosis involving the axillae , arms , abdominal folds , ears , and the face  suggestive of man .
compared to previous cases of gynaecological malignancy associated with man , our case also presented at a much younger age and also at an unusually young age for the diagnosis of endometrial carcinoma .
our patient also had cutis verticis gyrata , a rare clinical finding with cerebriform thickening of the scalp , manifesting as deep furrows and convoluted ridges .
this condition is commonly due to systemic disease , inflammatory dermatoses , underlying nevoid abnormalities , or trauma .
the condition has rarely been described in association with malignancy , and although the cause of our patient 's cutis verticis gyrata is not clear , the fact that it appeared in association with this patient 's endometrial carcinoma is of note .
although rare , man is often an initial sign of malignancy and should trigger extensive investigation .
this should include a review of systems including gastrointestinal symptoms , constitutional symptoms and a detailed gynaecological history .
initial investigations should include routine blood tests , chest x - ray , and also possible referral for endoscopy , breast examination , pap smear , pelvic examination / ultrasound , and other abdominal imaging if relevant .
in patients diagnosed with benign an , any atypical features or poor response to treatment should also raise the possibility of underlying malignancy .
this was depicted by the dual aetiologies in our patient and shows that physicians should have a low threshold for thorough investigation if malignancy is a possibility .
 acanthosis nigricans ( an ) is a dermatopathy associated with insulin - resistance , drugs , endocrine disorders , chromosomal abnormalities ( benign an ) , and neoplasia ( malignant an ) . 
 malignant an ( man ) is a rare paraneoplastic skin syndrome most commonly associated with gastric adenocarcinoma and other intra - abdominal malignancies . 
 we report the case of a 28-year - old female with an associated with obesity , insulin resistance , and endometrial adenocarcinoma . 
 although rare , man is often an initial sign of malignancy and must trigger extensive investigation , particularly in patients with sudden development of possibly paraneoplastic dermatoses or in patients diagnosed with benign an with any atypical features . 