Perform a general examination.



  • Age (>40 years of age, more likely to be associated with malignancy; more likelyto be associated with endocrinopathies in younger individuals)

  • Carcinoma of the stomach or other neoplasms (in 80% of cases the cancer isabdominal and in 60% of cases the cancer is in the stomach) - symptoms of weight loss,asthenia and decreased appetite.· Diabetes mellitus (insulin resistant diabetes)

  • Endocrinopathies: acromegaly, Cushing's disease, polycystic ovaries,hypo-thyroidism, hyperthyroidism.ExaminationBlack, velvety overgrowth seen in the axillae , neck, umbilicus, nipples, groin orfacial skin.

Proceed as follows:

Look for the following signs:

- Tripe palms (roughness of the pahnar and plantar skin).-Filiform growths around the face and mouth and over the tongue (when mouthand tongue are involved it is highly suggestive of an underlying neoplasm).· Tell the examiner that you would like to investigate for underlying malignancy, inparticular adenocarcinoma of the stomach and for endocrine disorders (diabetes,Cushing's syndrome, acromegaly).

Comment if the patient is obese or non-obese (when pigmented verrucous areasdevelop in the body folds of non-obese individuals about 80-90% have an under-lyinggastric cancer).




















This patient has a velvety black overgrowth in the axillae (lesion) and I would like toexclude an underlying adenocarcinoma, particularly of the stomach (aetiology).Read: lnt J Dermatol 1976; 15: 592; N Engl J Med 1987; 317: 1582.


What is the histology of acanthosis nigricans?

  • Undulating epidermis with numerous sharp peaks and valleys.

  • Variable amount of hyperplasia, hyperkeratosis and slight pigmentation of thebasal cell layer (but no melanocytic hyperplasia).

With which conditions is acanthosis nigricans associated?

  • Benign conditions

  • Diabetes associated with marked insulin resistance.

  • Cushing's syndrome.

  • Acromegaly.

  • Stein-Leventhal syndrome.Malignant conditions (due to abnormal production of epidermal growth factors) Adenocarcinomas (usually stomach, gastiointestinal tract, and uterus; Iess commonlylung, ovary, breast and prostate).

  • Lymphomas (rarely).

What is the relationship between the course of the skin lesion and the underlyingmalignancy?

The acanthosis nigricans may precede the neoplasm by more than 5 years. In abouttwo thirds of cases the course parallels that of the tumour, including remission with cure.Mention some cutaneous manifestations of visceral malignancy.

  • Dermatomyositis (in individuals older than 40 years the prevalence of internalmalignancy, particularly lung and breast cancer, is increased).· Migratory thrombophlebitis.· Ichthyosis (when acquired suggests gastrointestinal leiomyosarcoma,lymphoma, multiple myeloma).

  • Paget's disease of the nipple.

  • Tylosis or palmar hyperkeratosis (suggests oesophageal cancer).

  • Leser Trdlat sign, which is the sudden appearance of multiple seborrhoeickeratoses and suggests underlying cancer in the elderly.

  • Necrotic migratory erythema suggests alpha-cell tumours of the pancreassecreting glucagons.

  • Bazex's syndrome or acrokeratosis paraneoplastica suggests malignancy of theupper respiratory tract, particularly squamous cell carcinomas of the mouth, pharynx,larynx, oesophagus and bronchus.

  • Lymphomatoid papulosis is cutaneous lymphoid infiltration associated with T-celllymphomas or Hodgkin's disease.Acanthosis is hyperplasia of the stratum spinosum of theepidermis.