Topics A–Z
Free clinical monographs and reference pages covering common and rare cutaneous malignancy, pre-malignant disease, special populations, reconstructive practice and cancer syndromes encountered in UK practice.
432 topic pages · sorted alphabetically
A41 topics
Acanthosis nigricans
Tripe palms + mucosal = gastric adenocarcinoma.
Acne vulgaris
NICE NG198. EGFRi acneiform DDx.
Acquired digital fibrokeratoma
Solitary collarette finger/toe papule; excise.
Acquired hypertrichosis lanuginosa
Lanugo hair on face / trunk. Lung / GI / breast cancer.
Acquired ichthyosis
Hodgkin lymphoma the principal association.
Acral lentiginous melanoma
Palms, soles, nails. KIT-driven.
Acral melanocytic naevi
Parallel-furrow / lattice / fibrillar — benign.
Acrochordon (skin tag)
Multiple in young = Birt-Hogg-Dubé.
Acroangiodermatitis (pseudo-Kaposi sarcoma)
Venous hypertension / AV shunt; HHV-8 negative.
Acrodermatitis chronica atrophicans
Cigarette-paper atrophy on distal limbs.
Actinic cheilitis
10-30% cSCC precursor. Vermilionectomy.
Actinic keratosis
UV-induced dysplasia.
Acute radiation dermatitis
RTOG grading; emollients; topical steroid for G2+.
Adenoid cystic Ca of skin
Cribriform; perineural; MYB-NFIB fusion.
Adjuvant pembrolizumab IIB / IIC
KEYNOTE-716. TA837.
Adult T-cell leukaemia/lymphoma
HTLV-1; AZT/IFN, mogamulizumab.
AGEP
Sterile pustules. EuroSCAR. Pustular psoriasis DDx.
Aggressive digital papillary Ca
Distal digits. Pulmonary mets.
AJCC 8 melanoma stage groups
Stage 0–IV. AJCC 7→8 changes.
Allergic contact dermatitis
Patch testing diagnostic standard.
Amelanotic & hypopigmented melanoma
EFG rule. Pink / red / skin-coloured. 2-8% of melanomas.
Anal intraepithelial neoplasia
HRA, imiquimod, IRC. ANCHOR trial.
Anal melanoma
Aggressive mucosal melanoma; WLE preferred over APR.
Anal squamous cell carcinoma
HPV-16; AIN precursor; CRT (Nigro / ACT II).
Anetoderma
Buttonhole sign — herniated dermal patches.
Angiokeratoma
Solitary, Fordyce, Mibelli, Fabry.
Angiolipoma
Multiple tender. Young men. Familial.
Angioma serpiginosum
Serpiginous red puncta; non-blanching.
Anogenital warts
HPV 6 / 11. Gardasil-9. BASHH guideline.
Antibiotic prophylaxis in skin surgery
NICE NG125 + CG64. Risk-stratified.
Anticoagulation in skin surgery
Continue aspirin / DOAC / warfarin. BSDS / BAD.
Aplasia cutis congenita
Frieden 9 types. Scalp commonest.
Apocrine carcinoma
Axilla, anogenital, eyelid. Hormone-receptor positive.
Ataxia-telangiectasia
Ataxia + telangiectasias; lymphoma + breast (carriers).
Atopic eczema
Filaggrin / Th2. Dupilumab TA534.
Atrophie blanche / livedoid vasculopathy
Porcelain-white stellate scars. Rivaroxaban (RILIVAS).
Atypical fibroxanthoma
Pleomorphic dermal sarcoma cousin.
Atypical mycobacterial skin infection
M. marinum / Buruli / RGM. Long culture; clarithromycin.
Atypical squamous proliferation
Ambiguous biopsy term; correlate and sample adequately.
Atypical Spitz tumour / SAMPUS / MELTUMP
Specialist dermatopath + FISH / CGH / NGS.
Atypical vascular lesion
Post-RT precursor; MYC distinguishes.
B20 topics
Bacillary angiomatosis
Bartonella henselae / quintana. Doxycycline.
Bacterial folliculitis
S. aureus follicular pustules.
BAP1 tumour predisposition syndrome
BAPomas, uveal melanoma, mesothelioma.
Basal cell carcinoma
UK's commonest cancer. Slow, locally destructive.
Bazex paraneoplastic acrokeratosis
Acral psoriasiform; upper aerodigestive SCC.
Bazex-Dupré-Christol syndrome
X-linked dominant; multiple early BCCs + atrophoderma.
Becker naevus
ACTB mosaic; hypertrichosis from puberty.
BerEP4 (BCC IHC marker)
BCC vs cSCC vs adnexal.
Birt-Hogg-Dubé syndrome
Fibrofolliculomas, pulmonary cysts, RCC.
Bloom syndrome
Photosensitive butterfly erythema; >80% cancer risk.
Blue naevus & CBN
GNAQ/GNA11; ACBN intermediate.
Borrelial lymphocytoma cutis
Earlobe / nipple / scrotum; PCMZL mimic.
Bowen's disease
Squamous cell carcinoma in situ.
Bowenoid papulosis
HPV-driven; young adults; usually regresses.
BPDCN
CD4+ CD56+ CD123+; tagraxofusp appraisal TA782 terminated.
BRAF / MEK inhibitor cutaneous reactions
Secondary KA / cSCC; combo MEKi reduces; photosensitivity.
Breslow thickness
AJCC 8 cut-offs 0.8 / 1.0 / 2.0 / 4.0 mm.
Brooke-Spiegler syndrome
Cylindromas, spiradenomas, trichoepitheliomas.
Bullous pemphigoid
BP180/230. BAD 2022. Joly NEJM topical superpotent steroid.
BWH cSCC staging system
Jambusaria-Pahlajani factors; T1–T3.
C51 topics
Café-au-lait macule
≥6 of ≥5/15 mm → NF1 criterion.
Calciphylaxis
Necrotic ulcer in CKD. Sodium thiosulphate; warfarin off.
Cancer cachexia
Fearon staging. ESMO / ASCO multimodal.
Cancer syndromes — overview
Gorlin, BAP1, FAP, LFS, NF, TSC, XP, MEN.
Cancer Waiting Times standards
28-day FDS, 31-day, 62-day. NHSE 2023.
Cancer-related fatigue
70-100% in treatment. Exercise first-line.
Cardio-facio-cutaneous syndrome
BRAF / MEK; multiple naevi.
Carney complex
Spotty pigmentation, blue naevi, cardiac myxomas.
CD4+ small/medium T-cell LPD
WHO-HAEM5 / ICC: "LPD" (not lymphoma).
CD8+ aggressive epidermotropic CTCL
Berti's. Disseminated necrotic plaques.
Cellulitis
NICE NG141. CREST classes I-IV. Skin-oncology DDx.
Cherry angioma
Campbell de Morgan spot.
Chondrodermatitis nodularis helicis (CNH)
Painful pressure nodule of helix / antihelix; SCC/BCC mimic.
Chondroid syringoma
Cutaneous mixed tumour; rare malignant variant.
CK20 in Merkel cell carcinoma
Paranuclear dot. MCPyV link.
Clear cell acanthoma
Lower-leg red papule; dotted vessels in strings.
Cockade naevus
Concentric target-like rings.
Combined melanocytic naevus
Two distinct melanocytic components.
Common acquired melanocytic naevi
Junctional → compound → intradermal.
Common acquired naevi
BRAF V600E. Strongest single melanoma risk factor.
Completion lymphadenectomy
MSLT-II changed practice — observation now default.
Congenital melanocytic naevus
Small, medium, large, giant; NCM risk.
Conjunctival melanoma
BRAF/NRAS biology; PAM with atypia precursor.
Cowden syndrome
PTEN hamartoma TS.
ctDNA in melanoma
MRD detection, surveillance, response monitoring.
Curettage and cautery
C&C; low-risk BCC trunk; H-zone excluded.
Cutaneous abscess / furunculosis
I&D primary. CKS / NG141 if cellulitis.
Cutaneous angiosarcoma
Idiopathic, Stewart-Treves, post-RT.
Cutaneous AVM
Schobinger I-IV. CM-AVM (RASA1).
Cutaneous candidiasis
Intertrigo + satellite pustules. EMPD DDx.
Cutaneous CUP
Melanoma / cSCC nodal disease with occult primary.
Cutaneous endometriosis
Cyclical pain. Villar nodule.
Cutaneous epithelioid sarcoma
INI1 (SMARCB1) loss; sarcoma MDT; tazemetostat not NICE-commissioned.
Cutaneous Ewing sarcoma
EWSR1-FLI1 fusion; CD99+.
Cutaneous horn
Always biopsy the base.
Cutaneous immune-related adverse events
Maculopapular / lichenoid / psoriasiform / bullous / SJS-TEN.
Cutaneous leiomyoma
Multiple painful. HLRCC / FH gene.
Cutaneous leiomyosarcoma
Dermal vs subcutaneous.
Cutaneous leishmaniasis
Sandfly bite; travel history; liposomal amphotericin B.
Cutaneous mastocytosis
Darier sign; KIT D816V.
Cutaneous melanoma
Stage-directed multidisciplinary management; immune checkpoint inhibitors.
Cutaneous metastases
Sister Mary Joseph, en cuirasse.
Cutaneous pseudolymphoma
Borrelia, drug, tattoo, vaccination.
Cutaneous sarcoidosis
BCC / cSCC / lymphoma mimic; non-caseating granulomas.
Cutaneous squamous cell carcinoma
Most non-melanoma skin cancer mortality. BWH risk-stratification.
Cutaneous syphilis
Primary chancre / secondary protean / tertiary gummata.
Cutaneous T-cell lymphoma
Mycosis fungoides and Sézary. TNMB staging.
Cutaneous tuberculosis
Lupus vulgaris carries SCC risk after decades.
Cutaneous UPS
Beyond AFX/PDS spectrum.
Cutaneous γδ T-cell lymphoma
TCRγδ+; HLH; very poor prognosis.
Cylindroma
"Turban tumour" of Brooke-Spiegler.
D18 topics
Deep penetrating naevus
β-catenin (Wnt) activation; melanoma mimic.
Dermal melanocytosis (Mongolian spot)
Bruise mimic — document at newborn check.
Dermatofibroma
CD34 negative — distinguishes from DFSP.
Dermatofibroma variants
Cellular, aneurysmal and atypical variants; DFSP mimic.
Dermatofibrosarcoma protuberans
Indolent dermal sarcoma; COL1A1-PDGFB; imatinib.
Dermatosis papulosa nigra
Castellani — familial; cosmetic treat with care.
Dermoscopy in skin of colour
Pattern differences in Fitzpatrick IV–VI.
Desmoid tumour
CTNNB1 / APC. Active surveillance.
Desmoplastic melanoma
Amelanotic; high TMB; PD-1 highly responsive.
Diabetic dermopathy
Pretibial atrophic hyperpigmented spots.
Digital myxoid cyst
DIPJ; nail-plate groove; OA.
Discoid (nummular) eczema
Coin-shaped plaques. Tinea / psoriasis / MF DDx.
Discoid lupus erythematosus
Scarring plaques; SCC risk in chronic disease.
DLE-associated SCC
Aggressive SCC in scarring scalp / lip DLE.
DRESS syndrome
Eosinophilia + multi-organ. RegiSCAR. HHV-6/7.
Drug-induced hyperpigmentation
Minocycline / antimalarials / chemo / amiodarone.
Dyskeratosis congenita
Mucocutaneous triad + ~500× HNSCC.
Dysplastic / atypical naevus
Atypical naevus syndrome; FAMMM differential.
E26 topics
EB-associated cSCC
Leading cause of death in RDEB.
Eccrine porocarcinoma
Lower limb, elderly. ~20% nodal mets.
Eccrine poroma
Sole / palm. Mimics PG and amelanotic melanoma.
Eczema craquelé (asteatotic eczema)
Crazy-paving xerosis. CTCL mimic in older patients.
Eczema herpeticum & cutaneous HSV
Kaposi varicelliform on disrupted skin. HSV-1.
EGFR-inhibitor papulopustular eruption
STEPP doxycycline prophylaxis; predicts response.
Electrosurgery (diathermy, hyfrecation)
Monopolar / bipolar / hyfrecation. Pacemaker safety.
EMPSGC
Eyelid; precursor of mucinous Ca.
End-of-life skin cancer care
NICE NG142 / NG31. Anticipatory care.
Epidermoid cyst
Multiple in unusual sites = Gardner / FAP.
Epidermal naevus
Congenital verrucous plaques; ENS red flags.
Erosive pustular dermatosis of the scalp
Sterile crusted scalp erosions; SCC mimic.
Epithelioid haemangioendothelioma
WWTR1-CAMTA1 fusion; sirolimus.
Eruptive xanthomas
Severe hypertriglyceridaemia. Pancreatitis risk.
Erysipelas
Sharply demarcated; face / leg. NICE NG141.
Erythema ab igne
Modern causes: laptop, hot water bottle. SCC risk.
Erythema gyratum repens
"Wood-grain" pattern; lung Ca commonest.
Erythema migrans (early Lyme)
Bull's-eye 1-4 wk post tick bite. Doxy 21 days.
Erythema multiforme
True target lesions. Distinct from SJS.
Erythema nodosum
Streptococcal / sarcoid / IBD / TB / drug.
Erythrasma
Coral-red Wood lamp. Corynebacterium minutissimum.
Erythroderma
>90% BSA erythema + scaling. Inpatient supportive care.
Erythroplasia of Queyrat
Penile SCC in situ. HPV-driven.
Extramammary Paget's disease
Vulval / perianal / scrotal.
Extranodal NK/T-cell lymphoma, nasal
EBV-driven; SMILE/DDGP/asparaginase.
Eyelid margin basal cell carcinoma
Mohs first-line. Oculoplastic reconstruction by lamella.
F12 topics
Familial melanoma & CDKN2A
FAMMM, CDK4, BAP1, POT1.
Fanconi anaemia
BMF + head/neck and anogenital SCC.
Fibroepithelioma of Pinkus
Lumbosacral pink papule. Anastomosing basaloid trabeculae.
Fibrous papule of the face
Nasal angiofibroma — BCC mimic.
Field cancerisation
Topical 5-FU / imiquimod / tirbanibulin / PDT.
Fixed drug eruption
Same-site recurrence. Naevus / melanoma DDx.
Folliculotropic mycosis fungoides
Head & neck; eyebrow loss; RT first-line.
Fordyce spots
Ectopic sebaceous glands on lip / mucosa / genital.
Free flap principles
ALT, DIEP, radial forearm, fibula.
Frozen section in skin oncology
Margin assessment; not equivalent to Mohs.
Full-thickness skin graft (FTSG)
Wolfe graft. Face / eyelid / nose / ear.
Fungating skin wounds
Odour / exudate / bleeding / pain.
G7 topics
Gardner syndrome
FAP variant; epidermoid cysts, osteomas, desmoids, CHRPE.
Glomus tumour
Subungual painful triad.
Gorlin syndrome
Naevoid BCC syndrome.
Granular cell tumour
Tongue / skin / breast. PEH mimics SCC.
Granuloma annulare
Annular plaques; BCC / DF / lymphoma mimic.
Granuloma faciale
Red-brown facial plaque; eosinophils + Grenz zone.
Granulomatous slack skin
Pendulous axilla / groin skin. WHO-HAEM5.
H18 topics
Halo naevus (Sutton)
Depigmented halo of regression.
Hand-foot syndrome
TKI vs cytotoxic patterns; prophylaxis; CTCAE grading.
Hereditary haemorrhagic telangiectasia
Osler-Weber-Rendu. Curaçao criteria.
Hermansky-Pudlak syndrome
OCA + platelet δ-storage deficiency + lung fibrosis.
Herpes zoster (shingles)
ICI / immunosuppression. UK Shingrix.
Hidradenitis suppurativa
Hurley I-III; adalimumab TA392; SCC risk.
Hidradenocarcinoma
Aggressive; HER2 emerging target.
Hidradenoma
Clear cell variant; hidradenocarcinoma rare counterpart.
Hidradenoma papilliferum
Vulval / perianal apocrine — mammary-like gland.
Hidrocystoma
Cyst of Moll (apocrine) and eccrine variants.
HLRCC (Reed syndrome)
Painful leiomyomas + papillary RCC.
Hobnail haemangioma
Targetoid; hobnail vessels. Melanoma / KS mimic.
Howel-Evans (TOC)
Tylosis + 95% lifetime oesophageal SCC.
HS-associated cSCC
Marjolin spectrum in chronic perineal HS.
Hutchinson sign
Periungual pigment extending to nail fold.
Hyperhidrosis
Primary focal vs secondary (paraneoplastic).
Hypertrophic scar
Confined to wound margin. Often self-improves.
Hypomelanotic macule (ash-leaf)
≥3 of ≥5 mm → TSC criterion. Wood's lamp.
I13 topics
ICI-related colitis
5-40%. BSG / ESMO. Steroids → infliximab / vedolizumab.
ICI-related hepatitis
2-30%. ESMO grading. Avoid infliximab.
ICI-related hypophysitis
Anti-CTLA-4 10-17%. Adrenal crisis.
ICI-related pneumonitis
3-10%. COP / GGO patterns. Steroids.
ICI-related thyroid dysfunction
Most common. Biphasic. Levothyroxine.
Impetigo
NICE NG153. Hydrogen peroxide first-line.
In-transit melanoma metastases
T-VEC / ILP / ILI / ICI / RT.
Incontinentia pigmenti
Bloch-Sulzberger. IKBKG / NEMO.
Infantile haemangioma
GLUT1+. Proliferation→involution. Propranolol first-line.
Ink-spot lentigo
Reticulated dark solar lentigo. Sutton lentigo.
Inverted follicular keratosis
BCC/SCC mimic; squamous eddies on biopsy.
irAE-induced vitiligo
Predicts melanoma response. Photoprotect; do not suppress.
Irritant contact dermatitis
Healthcare workers 60-90%. Alitretinoin TA177.
J1 topic
Juvenile xanthogranuloma
Touton giant cells. JXG-NF1-JMML triad.
K6 topics
Kaposi sarcoma
HHV-8 angioproliferative tumour.
Kaposiform haemangioendothelioma
Kasabach-Merritt; sirolimus.
Keloid scar
Extends beyond wound margin. DFSP mimic. Multimodal.
Keratoacanthoma
Crateriform tumour; WHO: well-diff cSCC.
Keratosis pilaris
Autosomal dominant. KP alba / rubra / rubra faciei.
Klippel-Trénaunay syndrome
Port-wine + venous/LM + limb overgrowth.
L26 topics
Langerhans cell histiocytosis
BRAF V600E; vemurafenib.
Late radiation fibrosis and chronic post-RT skin change
Telangiectasia, fibrosis, alopecia; secondary malignancy risk.
Lentigo maligna
Melanoma in situ on facial skin.
Lentigo simplex
Small uniform brown macule of childhood.
LEOPARD / Noonan with lentigines
Lentigines + cardiac + deafness.
Leser-Trélat sign
Eruptive SKs; debated GI adenocarcinoma association.
Li-Fraumeni syndrome
Sarcoma + breast + brain + adrenocortical + melanoma.
Leukaemia cutis & myeloid sarcoma
Cutaneous leukaemic infiltrate; urgent haematology pathway.
Lichen amyloidosis & macular amyloidosis
Common Fitzpatrick IV-VI. CTCL DDx.
Lichen planus
5 Ps. Hypertrophic LP SCC risk on legs.
Lichen planus-like keratosis (BLK)
Inflamed regressing SK/lentigo; biopsy.
Lichen sclerosus
4-10% lifetime SCC risk.
Lichen simplex chronicus
Lichenified plaque. CTCL / cSCC mimic.
Lichen striatus
Blaschko-linear dermatitis.
Lifileucel (TIL therapy)
Autologous TIL — refractory melanoma. Amtagvi.
Lipodermatosclerosis
Inverted champagne bottle.
Lipoma
Sarcoma red flags: >5cm, deep, painful → MRI.
Local anaesthesia in skin surgery
Lidocaine / bupivacaine doses. LAST.
Local flap principles
Random vs axial. Advancement / rotation / transposition.
Locoregional melanoma recurrence
Local scar / satellite / in-transit / regional nodal.
Lymphangioma circumscriptum
Frog-spawn vesicles ± haemorrhage.
Lymphatic malformation
Macrocystic / microcystic / mixed. ISSVA 2018.
Lymphoedema (general overview)
Primary / secondary. ISL staging.
Lymphoedema after lymphadenectomy
ISL staging. CDT, LVA, VLNT.
Lymphomatoid papulosis
Self-healing papulonodular eruption.
Lymphovascular invasion
D2-40 lymphatic / ERG-CD31 vascular. NG14 SLNB trigger.
M20 topics
Malignant peripheral nerve sheath tumour
Painful enlarging NF1 lesion; sarcoma MDT.
Mammary Paget's disease
>95% have underlying breast carcinoma.
Marjolin's ulcer
SCC in chronic wounds and burn scars.
Melanoacanthoma
Heavily pigmented SK variant; melanoma mimic.
Melanocytic IHC panel
S100, SOX10, Melan-A, HMB-45, MITF.
Melanoma in situ
NG14 minimum 5 mm; LM often needs staged clearance.
MEN type 2B
Mucosal neuromas + childhood MTC + phaeo.
Merkel cell carcinoma
Rare aggressive polyomavirus-driven tumour. Avelumab.
Meyerson naevus
Eczematous halo; resolves with steroid.
Microcystic adnexal carcinoma
Infiltrative central-face Ca with PNI. Mohs.
Microsatellite instability (MSI)
MMR-IHC vs MSI-PCR; Lynch screening.
Milia
Multiple in syndromes (BDC, Rombo, BS).
Mitotic rate
NG14 SLNB discussion factor in 0.8–1.0 mm melanoma.
Molluscum contagiosum
Central umbilication. Mimics sebaceous hyperplasia, BCC.
MRI in melanoma surveillance
Brain MRI from stage IIB; soft-tissue MRI for in-transit.
Mucocele
Lip mucocele after lip biting; ranula on floor of mouth.
Mucosal melanoma
Distinct biology, worse prognosis.
Muir-Torre syndrome
Lynch variant.
Multicentric reticulohistiocytosis
Coral-bead periungual papules + erosive arthritis.
Mycosis fungoides
Patch/plaque/tumour; ISCL-EORTC TNMB; TSEB / brentuximab / mogamulizumab.
N18 topics
Naevoid melanoma
Mimics benign naevus. 1-2% of melanomas.
Naevus comedonicus
NEK9 mosaic. Syndromic association ~10%.
Naevus depigmentosus
Stable lifelong; non-syndromic.
Naevus lipomatosus superficialis
Soft fat naevus; mature adipocytes in dermis.
Naevus of Ota
Oculodermal melanocytosis.
Naevus sebaceus of Jadassohn
HRAS / KRAS mosaic; secondary tumours.
Naevus spilus
Speckled lentiginous naevus; HRAS mosaic.
Nail surgery (avulsion + matricectomy)
Phenol matricectomy. Subungual SCC / melanoma.
Necrobiosis lipoidica
Diabetic shin plaque; SCC in chronic ulcer.
Necrobiotic xanthogranuloma
IgG paraprotein; myeloma risk.
Necrolytic migratory erythema
Glucagonoma syndrome (4-D).
Necrotising fasciitis
LRINEC / SIARI. Cellulitis mimic.
Negative pressure wound therapy (NPWT)
VAC™ / TNP. Graft bolster, dehiscence, seroma prevention.
Neoadjuvant immunotherapy in melanoma
S1801, NADINA, PRADO.
Neurofibroma, schwannoma and traumatic neuroma
Painful-nodule differential; MPNST red flags.
Neurofibromatosis 1
Café-au-lait + neurofibromas; MPNST risk.
Nodular fasciitis
Rapid growth. USP6 rearrangement.
NTRK-fusion sarcoma
Larotrectinib / entrectinib.
O7 topics
Ocular surface squamous neoplasia (OSSN)
CIN → invasive SCC. Topical MMC / IFN; no-touch excision.
Oculocutaneous albinism
Dramatically increased SCC in equatorial settings.
Olmsted syndrome
Mutilating PPK + 5-10% SCC.
Onychomatricoma
Yellow nail with longitudinal cavitations.
Onychomycosis
DLSO / WSO / PSO / TDO. Confirm mycology before treating.
Oral leukoplakia
~1-2% per year SCC; PVL very high risk.
Oral lichen planus
WHO potentially malignant; ~1-3% SCC.
P50 topics
Paediatric melanoma
Modified Cordoro ABCDE; Spitzoid; CMN-associated.
Pagetoid reticulosis (Woringer-Kolopp)
Solitary acral plaque. Excellent prognosis.
Paraneoplastic dermatomyositis
Anti-TIF1-γ; ovarian, lung, breast, NPC.
Paraneoplastic pemphigus
NHL / CLL / Castleman. Bronchiolitis obliterans.
Paraneoplastic skin signs — overview
Curth criteria. Hub linking 16+ entities.
PD-L1 testing in skin cancer
22C3 / 28-8 / SP263 / SP142. TPS / CPS / IC.
Pearly penile papules
Hirsuties papillaris coronae glandis. Reassurance.
Pedicled / regional flap principles
Keystone, propeller, paramedian forehead.
Pediculosis (head, body, pubic)
Lice. NICE CKS. Dimeticone / malathion.
Penile squamous cell carcinoma
EQ / LS precursors. Penile-preserving surgery; ILND.
Perineural invasion
Calibre ≥ 0.1 mm / deep / named-nerve — BWH risk factor.
Perioral dermatitis
Spares vermilion. Rosacea mimic.
Periungual fibroma (Koenen tumour)
Multiple = tuberous sclerosis.
PET-CT in melanoma staging
Stage IIB+; not for early-stage routine staging.
Peutz-Jeghers syndrome
Mucocutaneous lentigines + GI polyposis.
Photoprotection and sunscreen
SPF / UVA-PA; 2 mg/cm² / 30 mL adult body.
Phytophotodermatitis
Streaks + hyperpigmentation. Lime / hogweed.
Piebaldism
White forelock + symmetric anterior leucoderma. KIT mutation.
Pigmented BCC
Leaf-like, blue-grey ovoid nests, spoke-wheel.
Pilar (trichilemmal) cyst
Scalp; multiple AD inheritance.
Proliferating trichilemmal tumour
Pilar-cyst-derived scalp tumour; malignant spectrum.
Pilomatrix carcinoma
CTNNB1 / β-catenin pathway.
Pilomatrixoma
Tent sign. CTNNB1 / β-catenin.
Pitted keratolysis
Plantar pits + foul odour. Kytococcus.
Pityriasis lichenoides (PLC / PLEVA)
PLC, PLEVA, FUMHD.
Pityriasis rosea
Herald patch + Christmas tree. HHV-6/7. ICI DDx.
Pityriasis versicolor
Malassezia. Mimics vitiligo / hypopigmented MF.
Plaque psoriasis
Mimics Bowen, MF, DLE; PUVA / TNFi cancer risk.
Pleomorphic dermal sarcoma
Higher-grade cousin of AFX.
POEMS syndrome
Glomeruloid haemangiomas; osteosclerotic myeloma.
Poikiloderma of Civatte
Lateral neck / chest; submental sparing.
Polymorphic light eruption
Spring / early summer. Lupus DDx.
Pompholyx (dyshidrotic eczema)
Sago-grain vesicles. EGFRi DDx.
Porokeratosis
Cornoid lamella; SCC progression.
Port-wine stain
Lifelong; GNAQ R183Q somatic. V1 → SWS.
POSAS & Vancouver scar scales
Patient + observer. UK BAPRAS-endorsed.
PRAME immunohistochemistry
Diffuse positivity supports melanoma over naevus.
Pretibial myxoedema
Waxy infiltrated pretibial plaques.
Primary cutaneous ALCL
ALK-negative; brentuximab vedotin.
Primary cutaneous B-cell lymphoma
PCMZL, PCFCL, PCDLBCL leg type.
Primary cutaneous DLBCL, leg type
Elderly female; lower leg; R-CHOP; MYD88 L265P.
Primary cutaneous follicle centre lymphoma
Commonest cutaneous B-cell lymphoma; RT or excision.
Primary cutaneous marginal zone lymphoma
Indolent; Borrelia in some; doxycycline / RT.
Primary cutaneous mucinous carcinoma
Eyelid/face nodule. Rule out metastasis.
Prurigo nodularis
Symmetric itchy nodules. CTCL differential.
Pruritus of malignancy
Hodgkin / polycythaemia / CTCL. NG12 red flag.
Pseudoepitheliomatous hyperplasia
Reactive squamous hyperplasia; superficial biopsy pitfall.
Pseudomonas (hot-tub) folliculitis
Swimwear distribution; self-resolves.
Punch biopsy technique
Trephine 2-8 mm. Workhorse biopsy.
Pyoderma gangrenosum
Pathergy! Major surgical / WLE trap.
R8 topics
RCPath margin reporting datasets
Minimum mandatory items. AJCC 8 / BWH alignment.
Recurrent naevus (pseudomelanoma)
Repigmentation of biopsy scar.
Reed's pigmented spindle cell naevus
Heavily pigmented; starburst dermoscopy.
Reflectance confocal microscopy
RCM; in-vivo cellular imaging; LM mapping.
Relaxed skin tension lines (RSTL)
Borges 1962. Pinch test.
Rombo syndrome
Vermiculate atrophoderma + BCCs.
Rosacea
ROSCO 2017. Phymatous → rhinophyma. BAD 2024.
Rothmund-Thomson syndrome
Poikiloderma + osteosarcoma.
S52 topics
Scabies (including crusted)
Sarcoptes scabiei. BAD 2019. Permethrin / ivermectin.
Schimmelpenning syndrome
Naevus sebaceus + CNS + eye + skeletal.
Sebaceoma
Intermediate sebaceous; MMR-IHC trigger.
Sebaceous adenoma
Trigger for Lynch / MMR-IHC.
Sebaceous carcinoma
Periocular Mohs + Muir-Torre screening.
Sebaceous hyperplasia
Major BCC mimic. Crown vessels.
Seborrhoeic dermatitis
Malassezia. ICI exacerbation.
Seborrhoeic keratosis
Major melanoma mimic. Sign of Leser-Trélat.
Senile / xerotic pruritus
Xerosis-driven. Always exclude malignancy if >6 weeks.
Sentinel lymph node biopsy
MSLT-I/II evidence base; NG14 §1.4.
Sézary syndrome
Mogamulizumab TA754; ECP; allogeneic SCT.
Shave biopsy technique
Tangential / saucerisation. AVOID in suspected melanoma.
Skin biopsy techniques
Punch / shave / incisional / excisional.
Skin cancer in chronic GVHD
Sclerodermatoid Marjolin; voriconazole risk.
Skin cancer in CLL
cSCC ~8×, MCC ~10-30×, melanoma ~3×.
Skin cancer in HIV
Kaposi, AIN/VIN, MCC; HAART optimisation.
Skin cancer in OTRs
cSCC roughly 65–100×; mTOR conversion.
Skin cancer in pregnancy
Surgery + SLNB safe; teratogenic systemic therapy.
Skin cancer in skin of colour
Acral / mucosal melanoma; Marjolin SCC.
Skin self-examination
Head-to-toe; ABCDE / ugly duckling.
Skin-cancer survivorship clinic
Stratified follow-up. HNA. Personalised care.
Smooth muscle hamartoma
Lumbosacral hypertrichotic patch. Pseudo-Darier.
Solar elastosis & Favre-Racouchot
Cutis rhomboidalis nuchae. Field cancerisation marker.
Solar lentigo
vs lentigo maligna on the face.
Solitary mastocytoma
Darier sign positive. KIT D816V. Avoid degranulators.
Sonidegib (Odomzo)
Locally advanced BCC. No positive NICE TA.
Specimen orientation & pathology liaison
RCPath datasets. Ink convention. Maps.
Spider naevus
Multiple in adults = chronic liver disease.
Spindle cell / pleomorphic lipoma
Posterior neck. 13q14 deletion.
Spindle-cell / sarcomatoid SCC
High-grade keratin-poor mimic.
Spiradenocarcinoma
Brooke-Spiegler context.
Spiradenoma
Painful blue-grey nodule. Brooke-Spiegler.
Spitz naevi & AST
Spitzoid spectrum; molecular profiling.
Spitzoid melanoma
HRAS / ALK / ROS1 / NTRK fusions. WHO 2023.
Split-thickness skin graft (STSG)
Epidermis + partial dermis. Workhorse for large defects.
Sporotrichosis
Gardener's nodule with sporotrichoid spread. Itraconazole.
SPTCL
αβ phenotype; mimics panniculitis; HLH.
Stasis dermatitis / venous eczema
Cellulitis mimic. NICE CG168 / CKS.
Steatocystoma multiplex
KRT17; pachyonychia congenita link.
Stevens-Johnson syndrome / TEN
Epidermal necrolysis. SCORTEN / ALDEN.
Stucco keratosis
Lower legs / ankles; lifts off without bleeding.
Sturge-Weber syndrome
V1 PWS + leptomeningeal + glaucoma. Aspirin / AEDs / PDL.
Subacute cutaneous lupus erythematosus
Anti-Ro; drug-induced / paraneoplastic variants.
Subungual exostosis
Distal phalanx; X-ray diagnostic.
Subungual melanoma
Hutchinson sign; functional vs amputation.
Subungual squamous cell carcinoma
HPV-16 associated; biopsy chronic nail change.
Sunbed exposure
UK Sunbeds Act 2010; no safe level.
Surgical site infection prevention
NICE NG125 bundle. Skin prep / normothermia.
Suture material selection
Absorbable vs non-absorbable. Site-specific.
Sweet syndrome
AML / MDS in paraneoplastic form.
Syringocystadenoma papilliferum
Pink scalp papule from naevus sebaceus.
Syringoma
Eyelid; "tadpole" ducts. Eruptive in Down.
T20 topics
Tebentafusp (Kimmtrak)
HLA-A*02:01 bispecific gp100 × CD3. TA1027.
Tinea pedis, corporis, cruris
Annular plaque + KOH. Tinea incognito with topical steroid.
Tissue expansion
Silicone expander + serial inflation. Scalp / face / breast / paediatric CMN.
Topical calcineurin inhibitors
Tacrolimus / pimecrolimus. FDA black-box.
Topical corticosteroids
UK potency ladder. FTU dosing. TSW.
Topical retinoids
Tretinoin / adapalene / tazarotene / trifarotene.
Total body photography and mole mapping
TBP / SDDI for high-risk patients.
Trichilemmal carcinoma
Outer-root-sheath malignancy.
Trichilemmoma
Multiple facial = Cowden / PTEN.
Trichoblastic carcinoma
Distinct from BCC.
Trichoblastoma
BCC mimic. CYLD (Brooke-Spiegler).
Trichoepithelioma
Multiple = Brooke-Spiegler / CYLD.
Trichofolliculoma
Central tuft of vellus hairs.
Trousseau sign of malignancy
Migratory thrombophlebitis; pancreatic Ca.
Tuberous sclerosis complex
Angiofibromas; topical / oral mTOR inhibitors.
Tufted angioma
Cannonball lobules. KMP risk; sirolimus.
Tumescent anaesthesia
Klein formula. Liposuction / lipoma / WLE.
Tumour budding
Bd1 / Bd2 / Bd3 — ITBCC 2016.
Tumour-infiltrating lymphocytes (TILs)
Clark grading; basis of TIL therapy.
Turcot syndrome
Type 1 (Lynch) / Type 2 (APC).
U3 topics
UK skin-cancer MDT principles
LSMDT vs SSMDT. NHSE service specification.
UV radiation and skin cancer
UVA vs UVB; IARC class 1.
Uveal melanoma
GNAQ/GNA11; tebentafusp (TA1027).
V9 topics
Venous lake
Compressible lip / face / ear lesion in elderly.
Venous malformation
TIE2 / PIK3CA. Localised intravascular coagulopathy.
Verruca vulgaris (common warts)
HPV-1/2/4. Periungual / digital biopsied as cSCC.
Verrucous carcinoma
Ackerman, Buschke-Löwenstein, cuniculatum.
Vitamin D and skin cancer
SACN 10 µg/day; supplementation over sun exposure.
Vitiligo
Non-segmental / segmental / focal. ICI response biomarker.
Vulval melanoma
KIT / NRAS biology; worse prognosis; 5-yr OS 30–50%.
Vulval squamous cell carcinoma
HPV-driven uVIN vs HPV-independent dVIN (lichen sclerosus).
Vulvar intraepithelial neoplasia
uVIN (HPV) and dVIN (LS-related).
W3 topics
Werner syndrome
Adult progeria; sarcomas + melanoma + thyroid.
Wide local excision
Margins by tumour, NG14 / BAD.
Wiskott-Aldrich syndrome
Eczema + thrombocytopenia + immunodeficiency.
X2 topics
Xanthelasma palpebrarum
Yellow eyelid plaques. CV risk marker.
Xeroderma pigmentosum
Severe early-onset multiple skin cancers.
Z1 topic
Z-plasty and W-plasty
Geometric scar revision. Lengthening / reorientation.