Table of Contents
Overview – Dermatoscopy Cases
Dermatoscopy (or dermoscopy) is a critical clinical skill in dermatology, particularly for the diagnosis and triage of pigmented skin lesions. It enhances the visualisation of subsurface structures and colours, allowing for more accurate differentiation between benign and malignant lesions. This case-based collection walks through 20 dermatoscopy cases, using the ABCD(EFG) criteria and the Three-Point Checklist to develop diagnostic confidence. Each case outlines clinical descriptors, key dermatoscopic features, diagnostic impressions, and appropriate management.
Case 1
Clinical Description:
- Small brown papule (9mm diameter)
- Irregular shape
ABCD (EFG) Criteria:
- Asymmetrical
- Border irregularity
- Colour variability
- Diameter increasing: unknown
- Evolving: unknown
- Elevated
Three Point Checklist Score:
- Asymmetry: Yes
- Atypical Network: No
- Blue-white Structures: Yes
Provisional Diagnosis:
- Potentially malignant BCC
Management:
- Excision
Case 2
Clinical Description:
- 5mm papular-plaque
- Brown with well-defined border
- Regular shape and pigment
- Ridges & fissures, comedo-like openings
ABCD (EFG) Criteria:
- Symmetrical
- Regular borders
- Regular colour
- Diameter not increasing
- Not evolving
- Elevated
Three Point Checklist Score:
- Asymmetry: No
- Atypical Network: No
- Blue-white Structures: No
Provisional Diagnosis:
- Benign Seborrheic Keratosis
Management:
- Monitor; no management needed
Case 3
Clinical Description:
- 1cm wide plaque
- Well-defined border
- Regular shape and pigmentation
ABCD (EFG) Criteria:
- Symmetrical
- Well-defined border
- Regular colour
- No diameter change
Three Point Checklist Score:
- Asymmetry: No
- Atypical Network: No
- Blue-grey Structures: Yes
Provisional Diagnosis:
- Benign Blue Naevus
Management:
- Monitor; no management needed
Case 4
Clinical Description:
- Small pigmented macule
- Irregular border
ABCD (EFG) Criteria:
- Symmetrical pattern, asymmetrical shape
- Irregular border
- Consistent colour
- No change in diameter or evolution
Three Point Checklist Score:
- Asymmetry: No
- Irregular Network: No
- Blue-grey Structures: No
Provisional Diagnosis:
- Ink-Spot Lentigo (Benign)
Management:
- None needed
Case 5
Clinical Description:
- Scaly raised, erythematous macule
- Poorly defined border with erythematous base
ABCD (EFG) Criteria:
- Asymmetrical
- Irregular border
- Consistent colour
- Increasing diameter
- Evolving
Three Point Checklist Score:
- Asymmetry: Yes
- Irregular Network: No
- Blue-grey Structures: Yes
Provisional Diagnosis:
- Amelanotic Melanoma (Malignant)
Management:
- Excision
Case 6
Clinical Description:
- Large pigmented plaque with warty surface
- Well-defined border, no history of change
ABCD (EFG) Criteria:
- Symmetrical shape, asymmetrical structure
- Well-defined border
- Consistent colour with an area of white regression
- Constant diameter
- No evolution
Three Point Checklist Score:
- Asymmetry: No
- Irregular Network: No
- Blue-white Structures: Yes
Provisional Diagnosis:
- Congenital Naevus (Benign Birthmark)
Management:
- None needed
Case 7
Clinical Description:
- Asymmetrical maculo-papular lesion
- Crusted surface, pigmented, large
- Presence of milia-like cysts and comedo-like openings
ABCD (EFG) Criteria:
- Asymmetrical
- Well-defined borders
- Regular colour
- Diameter ≈ 1cm
Three Point Checklist Score:
- Asymmetry: Yes
- Irregular Network: No
- Blue-white Structures: Yes
Provisional Diagnosis:
- Seborrheic Keratosis (Benign)
Management:
- None needed
Case 8
Clinical Description:
- Papular lesion on chest
- 7mm diameter
- Well-defined borders, regular shape
- Increasing in size over 12 months
ABCD (EFG) Criteria:
- Symmetry in shape, asymmetry in colour
Three Point Checklist Score:
- Asymmetry: Yes
- Irregular Network: No network
- Blue-white Structures: Yes
Provisional Diagnosis:
- Invasive Melanoma (Malignant)
Management:
- Excision
Case 9
Clinical Description:
- Pigmented macule
- Symmetrical with well-defined, regular border
- Enlarging; 1cm diameter
ABCD (EFG) Criteria:
- Symmetrical
- Regular border
- Regular colour
- Diameter 10mm
- Evolving: Yes
Three Point Checklist Score:
- Asymmetry: No
- Irregular Network: No
- Blue-white Structures: No
Provisional Diagnosis:
- Solar Lentigo (Benign)
Management:
- None needed
Case 10
Clinical Description:
- Pigmented macule
- Irregular colour and border
- Asymmetrical, long-standing
- Centre regression → white area
ABCD (EFG) Criteria:
- Asymmetrical
- Irregular border
- Irregular colour
- Diameter: 9mm
- Evolving: No
Three Point Checklist Score:
- Asymmetry: Yes
- Irregular Network: Yes
- Blue-white Structures: Yes
Provisional Diagnosis:
- Melanoma evolving within a dysplastic naevus
Management:
- Excision
Case 11
Clinical Description:
- Enlarging macule
- Irregular border
- Consistent colour
- Symmetrical
- Faint pigment network
ABCD(EFG) Criteria:
- Symmetrical
- Irregular border
- Consistent colour
- 1cm diameter
Three-Point Checklist Score:
- Asymmetry – Yes
- Irregular pigment network – No
- Blue-white structures – No
Provisional Diagnosis:
- Benign Solar Lentigo
Management:
- No treatment required
Case 12
Clinical Description:
- Pigmented papule
- Irregular border and colour
- Asymmetrical
ABCD(EFG) Criteria:
- Asymmetrical
- Irregular border and colour
- Diameter stable
- Not evolving
Three-Point Checklist Score:
- Asymmetry – Yes
- Atypical network – Yes
- Blue-white structures – Yes
Provisional Diagnosis:
- Melanoma
Management:
- Excision
Case 13
Clinical Description:
- Pigmented lesion with telangiectasia
- Ill-defined border
ABCD(EFG) Criteria:
- Asymmetrical
- Irregular colour and border
- 5mm diameter
Three-Point Checklist Score:
- Asymmetry – Yes
- Blue-white structures – Yes
- Irregular network – No
Provisional Diagnosis:
- Basal Cell Carcinoma (BCC)
Management:
- Excision
Case 15
Clinical Description:
- Diffuse, asymmetrical pigmented lesion
Three-Point Checklist Score:
- Asymmetry – Yes
- Irregular pigment network – Yes
- White structures – Yes
Provisional Diagnosis:
- Melanoma in situ
Management:
- Excision
Case 16
Clinical Description:
- Glomerular vessels
Three-Point Checklist Score:
- Asymmetry – Yes
Provisional Diagnosis:
- Bowen’s Disease (SCC in situ)
Management:
- Excision
Case 17
Clinical Description:
- Inverse pigment network
Three-Point Checklist Score:
- Asymmetry – Yes
- Irregular network – Yes
- Inverse pigment network – Yes
Provisional Diagnosis:
- Melanoma
Management:
- Excision
Case 18
Clinical Description:
- Fine telangiectasia
Three-Point Checklist Score:
- Asymmetry – Yes
- Blue-white structures – Yes
Provisional Diagnosis:
- Basal Cell Carcinoma (BCC)
Management:
- Excision
Case 19
Three-Point Checklist Score:
- Asymmetry – Yes
- Blue-white structures – Yes
- Irregular pigment network – Yes
Provisional Diagnosis:
- Melanoma
Management:
- Excision
Case 20
Three-Point Checklist Score:
- Asymmetry – Yes
- White structures – Yes
Provisional Diagnosis:
- Melanoma
Management:
- Excision
Summary – Dermatoscopy Cases
These dermatoscopy cases provide practical insight into recognising key visual features that distinguish benign lesions like seborrheic keratosis and solar lentigines from malignant conditions such as melanoma and BCC. Final-year medical students should become fluent in interpreting the ABCD(EFG) rule and Three-Point Checklist, as early excision of suspicious lesions remains the most effective intervention. Mastery of dermatoscopy significantly enhances diagnostic confidence in skin lesion assessment. For a broader clinical context, see our Skin & Dermatology Overview page.