• Velvety hyperpigmented plaques, most often in flexures (axillae, neck, groin)
• Common in insulin resistance (benign form)
• Sudden onset and extensive distribution → strong association with GI adenocarcinomas, especially gastric cancer
• Heliotrope rash, Gottron’s papules, periungual telangiectasia
• Proximal muscle weakness
• In adults >50, associated with underlying malignancy:
o Ovarian (especially in women)
o Lung
o Colorectal
o Pancreatic
• Erythematous, annular, blistering lesions with central clearing; affects perineum, groin, lower abdomen
• Strongly associated with glucagonoma (α-cell tumour of pancreas)
• Often accompanied by diabetes mellitus, weight loss, and glossitis
• Café-au-lait spots (≥6, >5 mm prepubertal, >15 mm postpubertal)
• Lisch nodules (iris hamartomas)
• Neurofibromas (cutaneous and plexiform)
• Increased risk of:
o Optic gliomas
o Phaeochromocytomas
o MPNST (malignant peripheral nerve sheath tumours)
• Facial angiofibromas (adenoma sebaceum)
• Shagreen patches (connective tissue nevus, often lower back)
• Ash-leaf macules (hypopigmented, Wood’s lamp aids detection)
• Periungual fibromas (Koenen’s tumours)
• Associated tumours:
o Renal angiomyolipomas
o Cardiac rhabdomyomas
o Subependymal giant cell astrocytomas
• Mucocutaneous pigmentation (lips, oral mucosa, perioral area)
• Multiple hamartomatous GI polyps
• Increased risk of:
o GI cancers (colorectal, pancreatic, gastric, small bowel)
o Breast, ovarian, cervical cancers
• Sudden onset of multiple, eruptive seborrhoeic keratoses
• Often pruritic
• Suggests underlying internal malignancy, commonly:
o GI adenocarcinomas (especially stomach)
o Less commonly lymphomas
Extra Revision Pearls
• New-onset, rapidly spreading acanthosis nigricans → always consider gastric adenocarcinoma
• NF1 vs NF2:
o NF1: cutaneous signs, optic gliomas
o NF2: bilateral vestibular schwannomas, minimal skin signs
• Necrolytic migratory erythema: classic "ring-shaped" migrating plaques → think glucagonoma
• Leser–Trélat sign: don’t confuse with benign slow-growing seborrhoeic keratoses
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Author & Educational Disclaimer
Author:
Dr Phillip Cockrell BM FRCP DipClinEd
Dr Phillip Cockrell is a UK Consultant Physician in Internal Medicine, currently working at Queen Alexandra Hospital, Portsmouth University Hospitals NHS Trust. He has previously worked as a registrar across Intensive Care Medicine, Gastroenterology, Cardiology, Stroke Medicine, Acute Medicine, and Respiratory Medicine.
He has held senior leadership roles including Associate Clinical Director of the Acute Medical Unit, Clinical Director of Internal Medicine, and Chief of Medicine. Dr Cockrell has over 15 years’ experience in postgraduate medical education, having lectured extensively across the MRCP syllabus and contributed to MRCP revision teaching and course development.
Dr Cockrell holds a Bachelor of Medicine (BM), Fellowship of the Royal College of Physicians (FRCP), and a Diploma in Clinical Education (DipClinEd). His teaching approach is based on structured consolidation of complex medical topics to support efficient and effective revision for postgraduate examinations.
Purpose of this content:
The material on this page is intended solely for educational purposes to support revision for the MRCP (UK) Part 1 examination. It reflects examination-relevant principles of internal medicine and is designed to aid learning and pattern recognition.
Medical disclaimer:
This content is designed for postgraduate medical examination revision and does not constitute medical advice, diagnosis, or treatment guidance and must not be used as a substitute for professional clinical judgement, local guidelines, or specialist consultation. Clinical decisions should always be made in the context of individual patient circumstances and current national guidance.
