Acquired hypertrichosis lanuginosa is a form of obligatorily paraneoplastic disease characterised by the recurrence of lanuga hair during adulthood. We report a case in which this hypertrichosis allowed diagnosis of gastric cancer.

A 51 year-old woman was seen for hypertrichosis present for 3 months. Clinical examination led to diagnosis of acquired hypertrichosis lanuginosa, which subsequently resulted in the discovery of gastric adenocarcinoma. Surgical excision of the tumour resulted in the disappearance of hypertrichosis with no recurrence during the ensuing 13 months.

Acquired hypertrichosis lanuginosa is rare, with only 50 or so cases reported in the literature since the condition was first described in 1865 by Turner. These cases confirm the obligatorily paraneoplastic nature of this particular dermatosis. Our finding is original since it is the first recorded case of association with gastric adenocarcinoma. It is also unique in terms of the strictly parallel development of acquired hypertrichosis lanuginosa and the tumour, with complete disappearance of the hypertrichosis in the weeks following surgical removal of the tumour, and in terms of prolonged survival (complete remission 17 months after the onset of symptoms). The mechanism responsible for acquired hypertrichosis lanuginosa is unknown. Two hypotheses have nevertheless been suggested: acquired hypertrichosis lanuginosa could be associated with secretion by the tumour of an as yet unidentified serum factor, or with a nutritional deficiency that may accompany this form of cancer.

Hypertrichosis is hair growth that is abnormal for the age, sex, or race of an individual, or for a particular area of the body. Recognized forms of hypertrichosis are reviewed. Hirsutism, which is male-pattern hair growth in a female or child, is not included in this review. Hypertrichosis is categorized as congenital or acquired, and regional or generalized. Methods of managing hypertrichosis are also briefly reviewed

Skin manifestations of systemic disease and malignancy are protean. The recognition of a potentially paraneoplastic dermatosis as such must prompt an investigation for occult malignancy. Lack of familiarity with cutaneous clues of internal malignancy may delay diagnosis and treatment of cancer. It is important to consider a paraneoplastic process in the differential diagnosis of a number of eruptive and treatment-resistant dermatoses. These dermatoses may be the first sign of an occult neoplasm. Their recognition may assist in cancer detection and the swift induction of appropriate therapy.

A 62-year-old woman with acquired hypertrichosis lanuginosa as a paraneoplastic presenting sign of an extraskeletal Ewing's sarcoma is described. Despite initial comprehensive screening to rule out an associated malignancy, a definitive diagnosis of sarcoma was established only 1 year after the onset of the cutaneous symptoms. To the best of our knowledge, this is the first report of hypertrichosis lanuginosa acquisita associated with a soft tissue sarcoma. Our observation expands the spectrum of malignancies associated with this uncommon paraneoplastic disorder.

Acquired hypertrichosis lanuginosa is a rare cutaneous disorder usually associated with internal malignancy that consists of the development of abnormal hair growth of the lanugo type, often confined to the skin of the face and neck, although other areas also may be involved. We report on a 66-year-old woman with a metastatic ductal infiltrating carcinoma of the breast who developed growth of fine lanugo type hair on her face and progressive growth of the hair of eyebrows and eyelashes. We review the literature on this uncommon paraneoplastic cutaneous disorder emphasizing the pathogenic mechanisms that have been proposed to explain the striking overgrowth of lanugo type hair.

The sign of Leser-Trélat is rare. It is defined as the sudden eruption of multiple seborrheic keratoses caused by a malignancy. Because both seborrheic keratoses and cancer are common in the elderly, it is not always easy to tell from the literature or in any given patient if this sign is present. In fact, its validity has been questioned. Its association with malignant acanthosis nigricans is one of several of its features that support its legitimacy as a true paraneoplastic disorder.

A variety of cutaneous disorders may reflect the presence of an internal disease. The ability to recognize those that may indicate an underlying malignancy is of particular importance. In part I of this series malignant involvement of the skin, either direct or metastatic, and the genodermatoses with malignant potential were reviewed. In this portion, we describe the paraneoplastic dermatoses as well as the cutaneous effects of some environmental carcinogens associated with internal malignancy. In addition, several uncommon and controversial associations between benign dermatoses and internal malignant disease will be discussed.