Skin Cancer

Question 1

What should be included in the ‘Assess’ phase when evaluating a rapidly growing scalp nodule?

Answer 1

• History:
* Onset, duration, and rapidity of growth
* Associated symptoms (bleeding, pain, ulceration)
* Risk factors for cutaneous malignancy (chronic sun exposure, prior skin cancers, immunosuppression)
* Systemic ‘red flags’ (weight loss, night sweats)
• Examination:
* Inspect lesion for size, color, consistency, border regularity, and ulceration
* Note adjacent actinic damage and chronic sun exposure signs
* Use dermoscopy to assess vascular patterns

Vascular patterns may include dotted, glomerular, or serpentine vessels.

Question 2

What are the malignant entities to consider in the differential diagnosis of a rapidly growing scalp nodule?

Answer 2

• Squamous Cell Carcinoma (SCC)
• Keratoacanthoma (KA)
• Amelanotic/Hypomelanotic Melanoma
• Merkel Cell Carcinoma (MCC)
• Atypical Fibroxanthoma/Pleomorphic Dermal Sarcoma (AFX/PDS)
• Cutaneous Metastasis

Histological features include keratin pearls in SCC and atypical melanocytes in melanoma.

Question 3

Which benign lesions must be considered in the differential for a rapidly growing scalp nodule?

Answer 3

• Epidermoid Cyst
• Pilar (Trichilemmal) Cyst
• Pilomatricoma
• Pyogenic Granuloma
• Deep Infections

A pilar cyst is common on the scalp and typically lacks a central punctum.

Question 4

What steps are involved in the ‘Decide’ phase for evaluating and managing a scalp nodule?

Answer 4

• Biopsy:
* Perform excisional or incisional biopsy
* Obtain tissue for histopathological examination
• Adjunctive Tests:
* Use dermoscopy for vascular and structural clues
* Consider imaging (MRI/CT) for deep invasion or metastasis suspicion
• Management:
* Complete surgical excision for benign lesions
* Refer for multidisciplinary team for malignancies

Histology helps differentiate lesions based on specific features.

Question 5

Can you summarize the overall evidence-based, structured approach using the ACD framework?

Answer 5

1. Assess:
   * Obtain a thorough history and conduct a detailed physical examination
2. Consider:
   * Develop a broad differential diagnosis including malignant and benign conditions
3. Decide:
   * Proceed with appropriate biopsy and tailor management based on results

This approach is supported by current dermatologic literature and guidelines.

Question 6

What is AFX?

Answer 6

AFX is a superficial variant of PDS.

Question 7

How do PDS behave compared to AFX?

Answer 7

PDS extend deep into the subcutis and behave more aggressively, with a 30% metastasis rate.

Question 8

What is the diagnosis method for PDS?

Answer 8

Diagnosis is by exclusion on histology.

Question 9

What type of tumor is associated with actinically damaged skin?

Answer 9

Spindle cell tumor is associated with actinically damaged skin.

Question 10

What are the differential diagnoses for spindle cell tumors?

Answer 10

Differential diagnoses include AFX, spindle cell SCC (p40/p-63), pan-ck, melanoma (sox-10/S-100), and leiomyosarcoma (desmin).

Question 11

What are the treatment options for spindle cell tumors?

Answer 11

Treatment options include wide local excision (WLE) with 1 cm margins or Mohs surgery with negative margins.