P18 A novel presentation of glycogenic acanthosis of the lip

Abstract

Abstract Glycogenic acanthosis (GAc) is a benign epithelial disorder, commonly observed in the oesophagus during endoscopy as multiple raised nodules affecting otherwise normal oesophageal mucosae (Tsai SJ, Lin CC, Chang CW et al. Benign esophageal lesions: endoscopic and pathologic features. World J Gastroenterol 2015; 21:1091). Despite its indolent disease course, oesophageal GAc is a minor diagnostic criterion for Cowden syndrome (CS). Glycogenic acanthosis affecting tissues other than the oesophagus is extremely rare. There have only been six cases of oral GAc reported to date, with no confirmed reports of GAc affecting the lip. We present the case of a 65-year-old White man with a 6-month history of asymptomatic white papules on the left lower lip. He was a lifelong nonsmoker. His past medical history was notable for colorectal cancer, which was in remission posthemicolectomy. He had also undergone ablative treatment for nasal polyps. He had no history of gastro-oesophageal reflux disease, or of thyroid disease, benign or malignant. Prominent facial actinic damage was present, and a biopsy was performed to rule out dysplasia. Histology demonstrated thickened hyperplastic epidermis and cytoplasmic clearing in the superficial epidermis. Keratinocytes with enlarged cytoplasm were positive on periodic acid–Schiff staining, supporting a diagnosis of GAc. On review, 3 months later, a single residual white papule was observed on the left lower lip. There were no other cutaneous features suggestive of CS. CS is caused by mutations in PTEN and is part of a spectrum of disorders known as PTEN hamartoma tumour syndrome (PHTS). It is associated with increased risk of solid-organ malignancies. Of the prior six reported cases of oral GAc, only one (Nishizawa A, Satoh T, Watanabe R et al. Cowden syndrome: a novel mutation and overlooked glycogenic acanthosis in gingiva. Br J Dermatol 2009; 160:1116–18) had a confirmed association with CS. Our patient remains under endoscopic surveillance but does not currently meet the criteria for either diagnosis or further genetic evaluation of CS. Oral glycogenic acanthosis may be an under-recognized entity due to its subtle clinical presentation. Biopsy and full-skin examination are warranted in suspected cases, to identify any association with an underlying genodermatosis.