Skin Tumours in MRCP Part 1: BCC vs SCC vs Melanoma
- Crack Medicine
- Mar 25
- 5 min read
TL;DR
For MRCP Part 1, recognising the differences between basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma is essential dermatology knowledge. The exam frequently tests lesion appearance, risk factors, metastatic potential, and basic management principles. In brief: BCC is locally invasive but rarely metastasises, SCC has moderate metastatic risk, and melanoma is aggressive with high metastatic potential. Mastering a few pattern-recognition clues can quickly unlock several dermatology MCQs.
Skin Tumours: BCC vs. SCC vs. Melanoma — MRCP Part 1 Guide
Why this matters
Dermatology contributes a steady number of questions in MRCP Part 1, and skin cancers are among the most consistently tested topics. Examination questions typically focus on clinical descriptions, epidemiology, pathology, and key prognostic indicators.
Candidates often struggle because the three major skin malignancies—basal cell carcinoma, squamous cell carcinoma, and melanoma—all arise in sun-exposed skin and may present with ulceration or pigmentation. However, the exam relies heavily on classic descriptions and pattern recognition.
By focusing on a few core features, candidates can rapidly differentiate these lesions in MCQs.
For broader exam preparation and topic coverage, see the MRCP Part 1 overview and practise clinical scenarios with Free MRCP MCQs.
Overview: Key Differences Between BCC, SCC and Melanoma
Feature | Basal Cell Carcinoma (BCC) | Squamous Cell Carcinoma (SCC) | Melanoma |
Cell of origin | Basal keratinocytes | Squamous keratinocytes | Melanocytes |
Growth pattern | Slow, locally invasive | Faster growth | Aggressive |
Metastasis | Very rare | Possible | High risk |
Typical lesion | Pearly papule with telangiectasia | Scaly, ulcerated nodule | Irregular pigmented lesion |
Typical site | Sun-exposed face | Sun-exposed areas | Anywhere (often trunk) |
Key risk factor | Chronic UV exposure | UV exposure, scars | Intermittent intense UV |
Prognostic factor | Rarely metastatic | Tumour size & depth | Breslow thickness |
Understanding these differences alone can help answer several dermatology questions in the exam.
The 5 Most Tested Subtopics
1. Basal Cell Carcinoma (BCC)
BCC is the most common skin cancer worldwide, accounting for roughly 80% of non-melanoma skin cancers.
Classic clinical description
MRCP questions often describe:
Pearly or translucent papule
Rolled edges
Surface telangiectasia
Central ulceration
A typical exam stem might read:
“A slowly enlarging pearly lesion with rolled borders on the nose.”
Key exam points
Rarely metastasises
Locally destructive if untreated
Occurs mainly on sun-exposed areas of the face
Treatment principle
First-line management is usually surgical excision or Mohs micrographic surgery, depending on lesion location and size.
2. Squamous Cell Carcinoma (SCC)
SCC is the second most common skin cancer and has greater metastatic potential than BCC.
Typical appearance
Common features include:
Hyperkeratotic or scaly nodule
Ulcerated surface
Indurated base
Important risk factors
Chronic ultraviolet exposure
Immunosuppression
Chronic inflammatory lesions or scars
Actinic keratosis
Clinical pearl
Actinic keratosis is a premalignant lesion that may progress to SCC, making this relationship a frequent examination topic.
3. Malignant Melanoma
Melanoma is the most dangerous skin malignancy due to its high metastatic potential.
The ABCDE rule
The exam commonly tests recognition using the ABCDE criteria:
A – Asymmetry
B – Border irregularity
C – Colour variation
D – Diameter greater than 6 mm
E – Evolution or change
Prognostic factor
The single most important prognostic factor is:
Breslow thickness
This measurement reflects tumour depth and strongly correlates with survival.
4. Patterns of Metastasis
Another commonly tested concept is metastatic potential.
BCC
Rare metastasis
Causes significant local tissue destruction
SCC
Can spread to regional lymph nodes
Melanoma
Early lymphatic spread
Can metastasise to lungs, liver, brain, and bone
This hierarchy of metastatic risk is often tested in comparison questions.
5. Management Principles
MRCP Part 1 focuses on general management principles rather than procedural details.
Typical management approaches:
BCC: surgical excision
SCC: excision ± lymph node evaluation
Melanoma: wide local excision with staging
Sentinel lymph node biopsy may be performed in melanoma depending on tumour thickness.
To practise exam-style questions on dermatology topics, try the Start a mock test.
High-Yield Exam Checklist
Use this quick revision list before attempting dermatology MCQs.
BCC rarely metastasises
SCC spreads to lymph nodes
Melanoma has the highest mortality
Pearly lesion with telangiectasia suggests BCC
Scaly ulcerated lesion suggests SCC
Irregular pigmented lesion suggests melanoma
Actinic keratosis is a precursor to SCC
Breslow thickness predicts melanoma prognosis
Sun exposure is the main environmental risk factor
Surgical excision is the standard treatment
Memorising these points significantly improves dermatology question accuracy.
Practical Example (MRCP-Style MCQ)
Question
A 65-year-old man presents with a slowly enlarging lesion on the side of his nose. Examination reveals a pearly papule with a rolled border and visible telangiectasia. The lesion occasionally bleeds but is otherwise painless.
What is the most likely diagnosis?
A. Actinic keratosisB. Basal cell carcinomaC. Squamous cell carcinomaD. Seborrhoeic keratosisE. Malignant melanoma
Correct answer: B. Basal cell carcinoma
Explanation
The key clinical descriptors are:
Pearly papule
Rolled border
Telangiectasia
Slow growth
These findings are classic for basal cell carcinoma.
SCC typically appears hyperkeratotic or ulcerated, while melanoma presents as irregular pigmented lesions with asymmetry and colour variation.
More dermatology practice questions are available in the Free MRCP MCQs.
Common Pitfalls
Confusing BCC with SCC The pearly appearance with telangiectasia strongly indicates BCC.
Forgetting Breslow thickness It is the most important prognostic factor in melanoma.
Assuming BCC frequently metastasises Metastasis is extremely rare.
Ignoring actinic keratosis as an SCC precursor This is a classic exam association.
Thinking melanoma only occurs in sun-exposed skin It commonly occurs on the trunk and back.
Practical Study-Tip Checklist
Before your dermatology revision session:
✔ Review classic lesion descriptions✔ Memorise BCC vs SCC vs melanoma differences✔ Understand metastatic patterns✔ Learn the ABCDE rule for melanoma✔ Practise dermatology MCQs daily
Structured teaching sessions can reinforce these concepts—see MRCP dermatology lectures.
FAQs
What skin cancers are most commonly tested in MRCP Part 1?
The exam most frequently tests basal cell carcinoma, squamous cell carcinoma, and melanoma, focusing on lesion appearance, risk factors, and key prognostic indicators.
What is the most important prognostic factor in melanoma?
The most important prognostic indicator is Breslow thickness, which measures the depth of tumour invasion and strongly predicts survival outcomes.
Which skin cancer rarely metastasises?
Basal cell carcinoma almost never metastasises but can cause significant local tissue destruction if untreated.
How can melanoma be recognised clinically?
Melanoma can often be recognised using the ABCDE rule: asymmetry, border irregularity, colour variation, diameter greater than 6 mm, and evolution of the lesion.
Is actinic keratosis malignant?
Actinic keratosis is premalignant and may progress to squamous cell carcinoma, especially in chronically sun-exposed skin.
Ready to start?
Dermatology questions in MRCP Part 1 are highly pattern-based. Once you understand the classic differences between BCC, SCC, and melanoma, many MCQs become straightforward.
To continue your revision:
Explore the MRCP Part 1 overview
Practise with Free MRCP MCQs
Reinforce concepts through MRCP lectures
Consistent question practice and visual pattern recognition remain the most effective strategies for mastering dermatology topics.
Sources
MRCP(UK) Examination Blueprint – https://www.mrcpuk.org
NICE Guidelines: Skin Cancer – https://www.nice.org.uk/guidance/ng12
British Association of Dermatologists – https://www.bad.org.uk
Kumar & Clark’s Clinical Medicine
Rook’s Textbook of Dermatology
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