# Clinical Cases: Skin Cancer

## Case 1: Basal Cell Carcinoma

### Patient Presentation
**Demographics:** 68-year-old male

**Chief Complaint:** Slowly growing "pimple" on nose that won't heal

**History of Present Illness:**
The patient noticed a small bump on his nose 8 months ago. He thought it was a pimple, but it has slowly enlarged. It occasionally bleeds when he washes his face. He has a history of significant sun exposure from working as a construction worker for 40 years.

**Past Medical History:**
- No prior skin cancers
- Fair skin, burns easily (Fitzpatrick type II)
- Extensive occupational sun exposure

**Physical Examination:**
- Nose (right ala):
  - 1.2 cm pearly, translucent papule
  - Rolled, raised borders
  - Central depression/ulceration with crusting
  - Telangiectasias (arborizing vessels) over surface
  - No significant scaling

### Workup and Results

**Dermoscopy:**
- Arborizing (tree-like) vessels
- Blue-gray ovoid nests
- Leaf-like structures
- No pigment network

**Shave Biopsy:**
- Nodular basal cell carcinoma
- Basaloid nests with peripheral palisading
- Retraction artifact between tumor and stroma

### Clinical Image

![Basal Cell Carcinoma](case_01_image.jpg)

*Clinical photograph showing nodular basal cell carcinoma on the nose with characteristic pearly, translucent appearance, rolled borders, central ulceration, and visible telangiectasias.*

### Diagnosis
**Nodular Basal Cell Carcinoma - High-Risk Location**

Features:
- Most common skin cancer
- Most common BCC subtype (nodular)
- Locally invasive but rarely metastasizes
- High-risk location (central face/"H-zone")

### Discussion
This case illustrates basal cell carcinoma:

- **Most Common Skin Cancer**: The lecture identifies BCC as the most common type of skin cancer, arising from basal keratinocytes.

- **Nodular BCC Features**: The lecture describes nodular BCC as having pearly/translucent appearance, telangiectasias, and rolled borders. Significant scaling is absent (unlike SCC).

- **Locally Invasive**: The lecture emphasizes that BCC rarely metastasizes but is locally invasive, which can cause significant tissue destruction, especially on the face.

- **Arborizing Vessels**: The lecture identifies arborizing (tree-like) vessels as a dermoscopic feature of BCC.

- **Mohs Surgery**: The lecture notes that Mohs micrographic surgery achieves cure rates exceeding 99% and is preferred for BCC in high-risk areas (face).

### Treatment Plan
1. **Mohs Micrographic Surgery (Preferred):**
   - Tissue-sparing technique
   - Same-day margin assessment
   - >99% cure rate
   - Indicated for high-risk location (nose)

2. **Alternative Options (if Mohs unavailable):**
   - Standard excision with 4mm margins
   - Electrodessication and curettage (not for this location)

3. **Follow-up:**
   - Full skin exam every 6-12 months
   - 50% of patients develop another BCC within 5 years
   - Sun protection counseling

4. **Patient Education:**
   - Daily sunscreen SPF 30+
   - Protective clothing and hats
   - Avoid peak sun hours
   - Monthly self-skin exams

### Teaching Points
1. BCC is the most common skin cancer; rarely metastasizes but locally invasive
2. Nodular BCC: Pearly, translucent with telangiectasias and rolled borders
3. Arborizing vessels on dermoscopy suggest BCC
4. Mohs surgery preferred for high-risk locations (>99% cure rate)
5. Morpheaform (sclerosing) BCC is the most aggressive subtype

---

## Case 2: Squamous Cell Carcinoma in Organ Transplant Recipient

### Patient Presentation
**Demographics:** 58-year-old male

**Chief Complaint:** Rapidly growing nodule on left forearm

**History of Present Illness:**
The patient noticed a small scaly patch on his forearm 6 months ago. Over the past 2 months, it has rapidly enlarged into a firm nodule. It is now 2.5 cm, tender, and occasionally bleeds. He received a kidney transplant 8 years ago and is on chronic immunosuppression.

**Past Medical History:**
- Kidney transplant 8 years ago
- Chronic immunosuppression: Tacrolimus, mycophenolate, prednisone
- Multiple actinic keratoses (treated with cryotherapy)
- History of two prior SCCs (excised)

**Physical Examination:**
- Left forearm:
  - 2.5 cm firm, indurated nodule
  - Central ulceration with keratinous crust
  - Surrounding erythema
  - Adherent to underlying tissue
  - Regional lymphadenopathy (left epitrochlear node palpable)

### Workup and Results

**Excisional Biopsy:**
- Invasive squamous cell carcinoma
- Moderately differentiated
- Depth: 6 mm
- Perineural invasion present
- Margins positive

**Staging Workup:**
- CT scan: Suspicious 2 cm epitrochlear lymph node
- Fine needle aspiration: Metastatic SCC

### Clinical Image

![Squamous Cell Carcinoma](case_01_image.jpg)

*Clinical photograph demonstrating squamous cell carcinoma presenting as a firm, indurated nodule with central ulceration and keratinous crust on the forearm of an immunosuppressed patient.*

### Diagnosis
**High-Risk Squamous Cell Carcinoma with Nodal Metastasis**

High-risk features present:
- Size >2 cm
- Depth >6 mm
- Perineural invasion
- Immunosuppression
- Regional lymph node metastasis

### Discussion
This case illustrates SCC in immunosuppressed patients:

- **Transplant Recipients at High Risk**: The lecture states that organ transplant recipients have a 65-fold increased risk for SCC. This is due to chronic immunosuppression and impaired immune surveillance.

- **Actinic Keratosis Precursor**: The lecture identifies actinic keratosis as a precursor lesion for SCC, with 1-10% progressing to invasive SCC.

- **Perineural Invasion**: The lecture notes that perineural invasion is a high-risk feature associated with increased metastasis and local recurrence.

- **Anti-PD-1 Therapy**: The lecture identifies anti-PD-1 immunotherapy (cemiplimab, pembrolizumab) as first-line treatment for advanced/metastatic SCC. However, use in transplant recipients requires careful consideration of rejection risk.

### Treatment Plan
1. **Surgical Management:**
   - Wide local excision with adequate margins (Mohs or standard excision)
   - Lymph node dissection for confirmed nodal disease

2. **Adjuvant Therapy:**
   - Consider adjuvant radiation to primary site and nodal basin
   - Discussion with transplant team about immunosuppression modification

3. **Immunotherapy Consideration:**
   - Cemiplimab or pembrolizumab for advanced disease
   - CAUTION: Risk of transplant rejection with checkpoint inhibitors
   - Requires multidisciplinary discussion

4. **Immunosuppression Modification:**
   - Consider conversion to sirolimus (mTOR inhibitor)
   - May have antiproliferative effects

5. **Surveillance:**
   - Frequent skin exams (every 3 months)
   - Field therapy for actinic keratoses (5-FU, imiquimod, PDT)

### Teaching Points
1. Organ transplant recipients have 65-fold increased SCC risk
2. Actinic keratosis is a precursor to SCC (1-10% progress)
3. Perineural invasion increases metastasis and recurrence risk
4. Anti-PD-1 immunotherapy is first-line for advanced SCC
5. Field cancerization requires field-directed therapy (5-FU, imiquimod, PDT)

---

## Case 3: Melanoma with Breslow Depth Assessment

### Patient Presentation
**Demographics:** 45-year-old female

**Chief Complaint:** Changing mole on her back

**History of Present Illness:**
The patient's husband noticed that a mole on her upper back has changed over the past 6 months. It has become darker, larger, and developed irregular borders. She reports it occasionally itches but has no pain or bleeding. She has a history of multiple sunburns as a child and teenager.

**Past Medical History:**
- Fair skin with multiple nevi
- History of blistering sunburns in childhood
- Family history: Father had melanoma at age 52

**Physical Examination:**
- Upper back:
  - 12 mm pigmented lesion
  - Asymmetric shape
  - Irregular, notched borders
  - Color variation: Brown, black, red, and blue-gray areas
  - The lesion looks different from her other moles ("ugly duckling")
- No palpable lymphadenopathy

### Workup and Results

**ABCDE Assessment:**
- **A**symmetry: Present
- **B**order irregularity: Present
- **C**olor variation: Present (multiple colors)
- **D**iameter: >6 mm (12 mm)
- **E**volving: Yes (changing over 6 months)

**Excisional Biopsy:**
- Malignant melanoma, superficial spreading type
- Breslow depth: 1.8 mm
- Clark level IV
- Ulceration: Absent
- Mitotic rate: 3/mm2
- Margins: Clear

**Staging:**
- LDH: Normal
- CT chest/abdomen/pelvis: No metastases
- PET scan: Negative
- BRAF V600E mutation: Positive

### Clinical Image

![Melanoma](case_01_image.jpg)

*Clinical photograph of melanoma demonstrating the ABCDE features: Asymmetry, Border irregularity, Color variation (brown, black, blue-gray), Diameter >6mm, and Evolution (history of change).*

### Diagnosis
**Melanoma, Superficial Spreading Type, Stage IIA (T2a N0 M0)**

Features:
- ABCDE criteria positive
- Superficial spreading (most common subtype)
- Breslow depth 1.8 mm
- BRAF V600E positive

### Discussion
This case illustrates melanoma diagnosis and staging:

- **ABCDE Criteria**: The lecture describes the ABCDE criteria: Asymmetry, Border irregularity, Color variation, Diameter >6mm, and Evolving. This patient meets all five criteria.

- **Superficial Spreading Most Common**: The lecture identifies superficial spreading as the most common melanoma subtype (70% of cases).

- **Breslow Depth**: The lecture emphasizes that Breslow depth (tumor thickness) is the most important prognostic factor for melanoma. This patient's 1.8 mm depth places her at intermediate risk.

- **BRAF Mutations**: The lecture notes that BRAF mutations are present in approximately 50% of melanomas, making patients eligible for targeted therapy if advanced disease develops.

- **Sentinel Lymph Node Biopsy**: The lecture recommends SLNB for melanomas with Breslow depth greater than 0.8-1.0 mm.

### Treatment Plan
1. **Wide Local Excision:**
   - 1-2 cm margins for 1.01-2.0 mm Breslow depth
   - 2 cm margin recommended for this 1.8 mm lesion

2. **Sentinel Lymph Node Biopsy:**
   - Indicated (Breslow >0.8 mm)
   - Staged with wide excision

3. **Adjuvant Therapy (if SLNB positive):**
   - Anti-PD-1 immunotherapy (pembrolizumab or nivolumab)
   - OR BRAF/MEK inhibitor (dabrafenib + trametinib)

4. **Surveillance:**
   - Clinical exam every 3-6 months for 2 years, then every 6-12 months
   - Annual full-skin exam for life
   - Consider imaging based on stage

5. **Patient Education:**
   - Sun protection
   - Monthly self-skin exams
   - Educate family members (increased risk)

### Teaching Points
1. ABCDE criteria: Asymmetry, Border, Color, Diameter >6mm, Evolving
2. Superficial spreading is the most common melanoma subtype
3. Breslow depth is the most important prognostic factor
4. SLNB recommended for melanomas >0.8-1.0 mm thick
5. BRAF mutations present in ~50%; targetable with BRAF/MEK inhibitors

---

## Case 4: Actinic Keratosis with Field Cancerization

### Patient Presentation
**Demographics:** 72-year-old male

**Chief Complaint:** Multiple rough patches on scalp and face

**History of Present Illness:**
The patient has noticed multiple rough, scaly patches on his bald scalp and face over the past several years. Some have been treated with cryotherapy in the past, but new ones keep appearing. He spent most of his career working outdoors as a farmer.

**Past Medical History:**
- Multiple actinic keratoses (previously treated)
- One SCC on ear (excised 3 years ago)
- Fitzpatrick type II skin

**Physical Examination:**
- Scalp:
  - Multiple (>15) erythematous, scaly papules and patches
  - 3-8 mm in size
  - Rough, sandpaper-like texture
  - Surrounding photodamaged skin with telangiectasias
- Face:
  - Multiple AKs on forehead and temples
  - Solar elastosis
- One lesion on right temple appears more indurated and thickened

### Workup and Results

**Clinical Assessment:**
- Field cancerization: Multiple AKs in sun-damaged skin
- One suspicious lesion (right temple) biopsied

**Biopsy (right temple lesion):**
- Squamous cell carcinoma in situ (Bowen disease)

### Clinical Image

![Actinic Keratoses](case_01_image.jpg)

*Clinical photograph showing multiple actinic keratoses on the bald scalp with characteristic rough, scaly appearance and surrounding photodamaged skin, demonstrating field cancerization.*

### Diagnosis
**Field Cancerization with Multiple Actinic Keratoses and SCC in Situ (Bowen Disease)**

Features:
- Multiple AKs in sun-damaged field
- One lesion progressed to SCC in situ
- High-risk patient (history of SCC, ongoing sun damage)

### Discussion
This case illustrates actinic keratoses and field cancerization:

- **Precursor Lesion**: The lecture identifies actinic keratosis as a precursor lesion for SCC, with 1-10% progressing to invasive carcinoma.

- **Field Cancerization**: The lecture describes field cancerization as multiple lesions in a sun-damaged area requiring field-directed therapy rather than individual lesion treatment.

- **Bowen Disease**: The lecture identifies Bowen disease as squamous cell carcinoma in situ (full-thickness epidermal dysplasia without dermal invasion).

- **Field-Directed Therapies**: The lecture lists field-directed options including topical 5-fluorouracil, imiquimod, and photodynamic therapy. Mohs surgery is lesion-specific, not field therapy.

### Treatment Plan
1. **For SCC in Situ (Right Temple):**
   - Excision with clear margins
   - OR Mohs surgery (cosmetically sensitive area)

2. **Field-Directed Therapy:**
   - Topical 5-fluorouracil (5-FU) 5% cream
     - Apply twice daily for 2-4 weeks
     - Expect significant inflammation (therapeutic)
   - OR Imiquimod 5% cream (3x/week for 4-8 weeks)
   - OR Photodynamic therapy (PDT)

3. **Individual Lesion Treatment:**
   - Cryotherapy for isolated thick lesions
   - Can be used in conjunction with field therapy

4. **Prevention:**
   - Daily sunscreen SPF 30+
   - Wide-brimmed hat
   - Avoid midday sun

5. **Surveillance:**
   - Skin exams every 3-6 months given history of SCC
   - Prompt evaluation of any changing or indurated lesions

### Teaching Points
1. Actinic keratosis is a precursor to SCC (1-10% progress)
2. Field cancerization requires field-directed therapy (5-FU, imiquimod, PDT)
3. Bowen disease = SCC in situ
4. UVB causes pyrimidine dimers (DNA damage)
5. Fitzpatrick type I-II at highest risk for skin cancer

---

## Image Reference

For visual reference of skin cancer concepts, see:
- Radiopaedia: [Basal cell carcinoma](https://radiopaedia.org/articles/basal-cell-carcinoma) - Clinical features
- Wikipedia: [Melanoma](https://en.wikipedia.org/wiki/Melanoma) - ABCDE criteria
- Radiopaedia: [Squamous cell carcinoma](https://radiopaedia.org/articles/cutaneous-squamous-cell-carcinoma) - High-risk features

---

## Learning Points

1. **BCC Features**: Pearly, translucent, arborizing vessels; Mohs achieves >99% cure

2. **SCC in Transplant**: 65-fold increased risk; anti-PD-1 is first-line for advanced disease

3. **Melanoma Prognostic Factors**: Breslow depth most important; SLNB for >0.8mm; BRAF in ~50%

4. **Actinic Keratosis**: 1-10% progress to SCC; field cancerization requires field therapy

5. **Surgical Margins for Melanoma**: In situ: 0.5-1cm; 1-2mm: 1-2cm; >2mm: 2cm