Surgery chapters
Cutaneous manifestations of generalised disease relevant to surgery and benign skin tumours
Skin signs of systemic disease that surgeons meet (syndromes, pyoderma gangrenosum, hidradenitis, skin infections) and the common benign skin lumps, naevi, cysts, scars and vascular lesions.
- Many systemic diseases show in the skin: NF1 (café-au-lait spots, neurofibromas), Gorlin syndrome (multiple BCCs), pyoderma gangrenosum with IBD, and necrotising fasciitis, a surgical emergency.
- Benign lumps include epidermoid (sebaceous) cysts with a punctum, naevi, seborrhoeic keratoses and vascular lesions.
- A strawberry haemangioma appears after birth and mostly involutes; a port-wine stain is present at birth and persists.
On this page
Overview
The skin often shows the first sign of a deeper disease, and surgeons see many skin lumps in clinic. This chapter covers two TOS subtopics:
- Skin signs of generalised disease that matter in surgery: inherited syndromes, inflammatory conditions, skin infections and purpura fulminans.
- Benign skin tumours: epidermal lesions, cysts, naevi, adnexal tumours, scars and vascular lesions.
Malignant skin tumours (BCC, SCC, melanoma) are covered in the next chapter.
Skin structure in brief
- Epidermis: keratinised stratified squamous epithelium in five layers (basalis, spinosum, granulosum, lucidum, corneum). It has no blood vessels.
- Melanocytes sit in the basal layer and come from the neural crest. Skin colour depends on how much melanin they make, not on how many melanocytes there are.
- Dermis: about 95% of skin thickness; papillary (superficial) and reticular (deep) layers.
- Adnexa (hair follicles, sebaceous and sweat glands) reach into the dermis. After a partial-thickness injury, new epidermis grows from them as well as from the wound edges.
- Apocrine glands are in the axilla and groin and become active at puberty. Eccrine glands cover the whole body except the lips.
Cutaneous manifestations of generalised disease
Inherited syndromes
| Syndrome | Inheritance and gene | Skin and other features |
|---|---|---|
| Neurofibromatosis type 1 (von Recklinghausen) | Autosomal dominant; chromosome 17 | More than five café-au-lait spots, cutaneous neurofibromas, axillary or groin freckling, Lisch nodules in the iris |
| Gorlin syndrome (naevoid BCC syndrome) | Autosomal dominant; PTCH ("patched") gene, chromosome 9q | Multiple BCCs, bifid ribs, palmar pits, odontogenic jaw cysts, wide-set eyes |
| Xeroderma pigmentosum | Autosomal recessive; faulty DNA (nucleotide excision) repair | Severe UV sensitivity, early skin ageing, many skin cancers from childhood |
| Gardner syndrome | Autosomal dominant; variant of FAP (chromosome 5) | Multiple epidermoid cysts, lipomas, osteomas, colonic polyps |
| Ferguson-Smith syndrome | Autosomal dominant; chromosome 9q | Multiple self-healing SCCs (keratoacanthoma-like) |
| Tuberous sclerosis | Autosomal dominant | Adenoma sebaceum (facial angiofibromas on the nasolabial folds and cheeks) |
In NF1, the tumours are formed by Schwann cells. Many smooth-edged café-au-lait spots point to NF1 or McCune–Albright syndrome.
Skin signs of systemic disease seen by surgeons
| Skin sign | Linked disease |
|---|---|
| Pyoderma gangrenosum | Inflammatory bowel disease, rheumatoid arthritis, lymphoma, granulomatosis with polyangiitis |
| Necrobiosis lipoidica, granuloma annulare | Diabetes mellitus |
| Spider naevi | Chronic liver disease, pregnancy |
| Lipodystrophy (fat loss) | Long-term insulin injections, HIV protease inhibitors |
| Purpura fulminans | Meningococcal or varicella sepsis, asplenia |
| Multiple epidermoid cysts and lipomas | Gardner syndrome |
Pyoderma gangrenosum is a painful ulcer with a purple, undermined edge. It is an exaggerated immune reaction, not an infection. It responds to steroids. Surgery is rarely needed and can make it worse (pathergy).
Pyoderma gangrenosum looks like an infected ulcer, but debriding it makes it bigger. Think of it when an ulcer grows after surgery in a patient with IBD.
Hidradenitis suppurativa affects skin with apocrine glands (axilla, groin, perineum). Hair follicles block and become infected, giving recurrent painful abscesses, sinus tracts and scarring. It is more common in women and is linked with obesity and smoking. Treat with weight loss, stopping smoking, antiseptic washes, antibiotics and antiandrogens; severe disease needs radical excision of the affected skin and reconstruction.
Hyperhidrosis is excess eccrine sweating of the palms, soles and axillae. Options are antiperspirants, botulinum toxin A injections and, for resistant cases, thoracoscopic sympathectomy.
Purpura fulminans is rapid skin necrosis from small-vessel thrombosis. The common acute infectious type follows meningococcal or varicella infection, usually in young children. Endotoxin causes protein C deficiency; petechiae become bullae and black eschars, often leading to amputation.
Skin and soft tissue infections
| Infection | Organism and level | Key features | Treatment |
|---|---|---|---|
| Impetigo | Staphylococci and/or streptococci; superficial epidermis | Children; blisters that leave a honey-coloured crust; very contagious | Washing, topical antistaphylococcal agent; oral antibiotic if streptococci involved |
| Erysipelas | Streptococci; superficial dermal lymphatics | Sharply demarcated, raised red area, often on the face | Antibiotics after a swab |
| Cellulitis | Usually streptococci; dermis and subcutaneous tissue | Spreading red, hot, swollen skin, fever; may show lymphangitis | Cultures, IV antibiotics, elevation |
| Necrotising fasciitis | Polymicrobial (group A β-haemolytic streptococcus with staphylococci, coliforms, anaerobes) | Pain out of proportion, woody induration, oedema beyond the redness, blisters, crepitus, rapid septic shock | Resuscitation, high-dose IV antibiotics and urgent radical debridement |
Necrotising fasciitis is a surgical emergency. Do not wait for imaging. Even with surgery, mortality is about 30–50%. Fournier's gangrene is the same process in the perineum and scrotum; Meleney's synergistic gangrene is another variant.
Risk factors for necrotising fasciitis: diabetes, smoking, immunosuppression, IV drug use, penetrating trauma, pressure sores and perineal infection.
Skin and subcutaneous cysts
| Cyst | What it is | Clues |
|---|---|---|
| Epidermoid ("sebaceous") cyst | Lined by stratified squamous epithelium, from the hair follicle opening | Fixed to skin, central punctum, anywhere except palms and soles |
| Pilar (tricholemmal) cyst | From the outer root sheath of the hair follicle | Mostly on the scalp; often multiple |
| Implantation dermoid | Squamous epithelium pushed under the skin by a penetrating injury | Fingers of tailors, gardeners, farmers |
| Sequestration dermoid | Skin trapped where embryonic processes fuse | External angular dermoid at the outer eyebrow, midline of the face and neck |
| Milia | Tiny keratin retention cysts | Babies and sun-damaged elderly skin |
Management of an epidermoid cyst:
- If infected: incise and drain first, then excise once inflammation settles.
- If quiet: excise completely with its wall (and the punctum), or it will recur.
An implantation dermoid is acquired (trauma), while a sequestration dermoid is congenital. Neither is a hamartoma.
Benign epidermal and pigmented lesions
Epidermal lesions
- Seborrhoeic keratosis (basal cell papilloma): "stuck-on", warty, often pigmented lesion of older people. Harmless.
- Viral wart (verruca vulgaris): due to human papillomavirus; the same virus family causes plantar and genital warts.
- Freckle (ephelis): normal number of melanocytes making extra melanin.
- Lentigo: small flat pigmented spot from sun damage.
- Rhinophyma: end-stage nasal acne rosacea with sebaceous gland overgrowth, mostly in elderly men; treated by dermabrasion or laser.
Naevi (moles)
| Naevus | Features |
|---|---|
| Junctional | Flat, dark; naevus cells at the dermo-epidermal junction; childhood |
| Compound | Raised and pigmented; junctional activity plus dermal nests; adolescence |
| Intradermal | Pale, dome-shaped in adults; cells only in the dermis |
| Spitz | Red-brown nodule in children (old name "juvenile melanoma"); excise if any doubt about melanoma |
| Halo | Ring of depigmentation from an immune reaction; linked with vitiligo |
| Blue naevus | Deep dermal melanocytes; blue-black on the face or limbs |
| Mongolian spot | Blue-grey patch over the sacrum at birth; fades in early childhood |
| Naevus of Ota / Ito | Blue-grey dermal melanocytosis in the trigeminal (V1, V2) area / shoulder region |
| Giant congenital naevus | Large hairy naevus in a dermatomal pattern; real melanoma risk; may involve the meninges |
| Atypical (dysplastic) naevus | Irregular colour and edge, larger size; many of them raise melanoma risk |
Lesions with malignant potential include giant congenital naevi, atypical (dysplastic) naevi and spindle cell naevi. Ordinary acquired moles rarely turn malignant.
Adnexal tumours
- Pilomatrixoma: hard, often calcified nodule from hair matrix cells; common in children.
- Trichoepithelioma: small skin-coloured nodule on the nasolabial fold; looks like BCC under the microscope.
- Naevus sebaceous of Jadassohn: congenital linear warty plaque on the scalp; a small proportion develop BCC.
- Cylindroma: multiple scalp nodules that can merge into a "turban tumour".
Lipoma
A lipoma is a soft, lobulated, mobile, painless lump of mature fat in the subcutaneous tissue. The edge slips under the examining finger. Excise if it is large, symptomatic, growing fast or deep to the fascia (to rule out liposarcoma).
Scars: hypertrophic and keloid
| Feature | Hypertrophic scar | Keloid |
|---|---|---|
| Extent | Within the wound boundary | Beyond the wound boundary |
| Natural course | Improves with time | Does not regress |
| Risk factors | Deep dermal burns, wounds across tension lines | Dark skin, family history, sternum, shoulders, earlobes |
| After excision | Can improve | High recurrence |
Treatments for both: pressure garments, silicone gel sheets and intralesional steroid (triamcinolone). Excision for keloid is combined with steroid injection or radiotherapy because recurrence is common.
After a deep burn, the raised scar that stays inside the burn area is hypertrophic, and the first-line treatment is pressure garments, not excision.
Vascular lesions
Haemangioma versus vascular malformation
| Feature | Infantile (strawberry) haemangioma | Vascular malformation (e.g. port-wine stain) |
|---|---|---|
| Nature | Benign endothelial tumour | Error of vessel development |
| At birth | Often absent or a small herald patch | Always present (may be hidden if deep) |
| Course | Grows fast in the first year, then involutes | Grows in proportion with the child; never involutes |
| Sex | More in girls | Equal |
| Treatment | Observe; treat if it blocks the eye, airway or bleeds | Pulsed dye laser or intense pulsed light for port-wine stains |
- Strawberry naevus (capillary haemangioma): the commonest birthmark, usually on the head and neck. About 70% have resolved by age 7, so reassurance and observation is the usual answer.
- Kasabach–Merritt syndrome: a large vascular tumour traps platelets, causing thrombocytopenia.
- Salmon patch: pink mark on the nape of the neck, usually fades by 1 year.
- Port-wine stain: flat purple stain present at birth, often in trigeminal territory, persists for life; may be part of a syndrome (e.g. Sturge–Weber).
Strawberry Shrinks; Port-wine Persists.
Acquired vascular lesions
| Lesion | Key point |
|---|---|
| Campbell de Morgan spots | Small red papules on the trunk of older adults; harmless |
| Spider naevi | Central arteriole with radiating vessels; pregnancy, liver disease |
| Pyogenic granuloma | Soft red nodule that bleeds easily after minor trauma; excise with a small margin |
| Glomus tumour | Small purple nodule, often under the nail, with severe pain triggered by cold or touch |
| Kaposi sarcoma | Malignant; HHV-8; linked to HIV and transplant immunosuppression |
| Angiosarcoma | Malignant; can arise in long-standing lymphoedema |
Expect: features of NF1 (café-au-lait spots, neurofibromas, Lisch nodules), Gorlin syndrome and xeroderma pigmentosum as skin-cancer syndromes, pyoderma gangrenosum with IBD, the signs and urgent debridement of necrotising fasciitis, the punctum of an epidermoid cyst and need for complete excision, the trauma origin of an implantation dermoid, keloid versus hypertrophic scar, strawberry naevus that resolves versus port-wine stain that persists, and the painful subungual glomus tumour.
Quick revision
- NF1: café-au-lait spots (more than five), neurofibromas, freckling, Lisch nodules; chromosome 17.
- Gorlin: multiple BCCs, bifid ribs, palmar pits, jaw cysts.
- Xeroderma pigmentosum: autosomal recessive DNA repair defect; early skin cancers.
- Pyoderma gangrenosum: undermined purple edge; IBD; steroids, not surgery.
- Necrotising fasciitis: pain out of proportion, crepitus; resuscitate and debride urgently.
- Epidermoid cyst: punctum; excise whole. Implantation dermoid: trauma.
- Keloid beyond the wound; hypertrophic scar within it.
- Strawberry naevus involutes (observe); port-wine stain persists (laser).
- Glomus tumour: painful, cold-sensitive, subungual.
Written by The House Job from standard surgical references (Bailey & Love).
FAQ
What is the difference between a keloid and a hypertrophic scar?
A keloid spreads beyond the edges of the original wound and rarely settles, while a hypertrophic scar stays within the wound and usually improves with time.
Should a strawberry naevus be removed?
Usually not. Most shrink by themselves over the first years of life, so observation is advised unless it threatens vision, the airway or bleeds.
Why does an epidermoid cyst recur after surgery?
Because part of its epithelial lining was left behind. The whole cyst wall, including the punctum, must be removed once any infection has settled.
How does an implantation dermoid form?
A penetrating injury, often to a finger, pushes surface squamous cells into the subcutaneous tissue, where they grow into a keratin-filled cyst.