ACANTHOSIS NIGRICANS: THE TELLTALE SIGN OF A GASTRIC CANCER RECURRENCE

Background: Acanthosis nigricans (AN) is a skin condition characterized by focal or diffuse hyperkeratotic, symmetrically distributed hyperpig- mented lesions of skin or mucous membranes. It has been associated with a wide spectrum of diseases such as type 2 diabetes mellitus, obesity, drugs and malignancies (Malignant Acanthosis Nigricans, MAN). MAN mostly occurs in elderly patients, without gender differences and its most com- mon cause is gastric cancer (55-61%), followed by pancreatic, gynecolog- ical and pulmonary malignancies. Coexisting neoplasm should always be suspected in elders with new onset AN. Here we present the case of a woman with severe MAN associated with gastric adenocarcinoma. Skin lesions disappeared after treatment. In our case, development of MAN represented the first sign of tumour recurrence. Materials and Methods: We report a case of malignant acanthosis nig- ricans associated with both onset and recurrence of gastric carcinoma. A 63 years old woman presented with hyperkeratotic, papillomatous plaques on neck, armpits and chest. Endoscopy revealed an extensive ulcerated gastric neoplasm. Surgical resection and adjuvant chemotherapy were followed by complete regression of the skin lesions. Unfortunately after 8 months cancer recurrence occurred and it was preceded by development of malignant acanthosis nigricans. Results: MAN is a rare paraneoplastic condition often associated with malignancies: the most common is gastric carcinoma (55-61% of all MAN cases). Prevalence of MAN is estimated to be 2/12000 cancer patients. Its pathogenesis remains unclear: TGF-alpha secretion and EGF-R hyper- expression may play a role in the development of skin lesions. Usually MAN is more severe and spreads faster than AN associated with benign pathologies. MAN regression is observed in 90-95% of patients who un- dergo treatment of the primary tumour: the skin lesions usually are resistant to conventional treatments such as corticoids or vitamin D. Although in literature there are several cases of MAN in patients with primary gastric neoplasm, to our knowledge only one paper reports the development of MAN in gastric cancer recurrence (Tab. 1). Conclusions: In conclusion, acanthosis nigricans has a wide range of underlying causes but it always has to be investigated as it may lead to the diagnosis either of a malignancy either of its recurrence. It could be therefore considered pathognomonic for tumour recurrence in elder pa- tients with positive history for abdominal neoplasms.