What is the appropriate management for a 66‑year‑old man with a month‑old, non‑healing, itchy, pink‑erythematous, irregularly shaped, raised lesion on his left forearm?

Urgent Excisional Biopsy Required

This 66-year-old man with a month-old, non-healing, pink/erythematous, irregularly shaped, raised lesion on his left forearm requires immediate excisional biopsy to rule out squamous cell carcinoma (SCC) or other malignancy. The clinical features—non-healing for one month, irregular borders, raised appearance, and location on sun-exposed skin—are concerning for skin cancer and mandate tissue diagnosis before any other treatment 1.

Why Excisional Biopsy is Standard of Care

The guideline evidence is unequivocal: cutaneous lesions should be excised rather than biopsied for three critical reasons 1:

• If the lesion is benign, no further treatment is needed
• Partial examination risks misdiagnosis
• Complete examination is necessary to assess all histological parameters, particularly maximum thickness

Perform excisional biopsy with a 2-mm margin of normal skin using a scalpel (not laser or electrocautery), with the long axis parallel to skin lines—in this case, longitudinally down the forearm 1. This orientation allows for re-excision with minimal skin loss if malignancy is confirmed and prevents interference with potential sentinel node biopsy if needed.

Differential Diagnosis Considerations

While awaiting histology, the key differentials based on clinical presentation include:

Malignant possibilities (highest priority):

• Squamous cell carcinoma - most likely given non-healing nature, sun-exposed location, age, and duration
• Basal cell carcinoma - pink/erythematous appearance fits
• Melanoma (amelanotic variant) - irregular borders and evolution criteria present 1

Premalignant:

• Actinic keratosis (hypertrophic variant) - though typically these are thinner and respond to initial therapy 2, 3, 2

Inflammatory (less likely but consider):

• Pyoderma gangrenosum - though typically more painful and rapidly progressive 4, 5
• Atypical presentation of inflammatory dermatosis - but one month duration without response makes this less likely

Critical Red Flags Present

This lesion demonstrates multiple concerning features that mandate urgent evaluation 2, 6:

• Non-healing for one month - any lesion not responding to appropriate therapy requires biopsy
• Irregular borders - malignancy criterion
• Raised/thickened - suggests substance when palpated, concerning for invasive disease
• Sun-exposed location (forearm) - high-risk site for skin cancer
• Age 66 - peak incidence for non-melanoma skin cancer

Common Pitfall to Avoid

Do not attempt empiric treatment with topical therapies, cryotherapy, or antibiotics without tissue diagnosis. The guidelines explicitly warn that actinic keratoses with atypical clinical appearance or failure to respond to appropriate therapy should be biopsied for histologic evaluation 6, 3. This lesion has already been present and "non-healing" for a month—it has failed to resolve spontaneously and requires definitive diagnosis.

Do not perform a shave biopsy, punch biopsy, or incisional biopsy as first-line unless the lesion size or location absolutely precludes excisional biopsy 1, 7. The forearm location allows for complete excision.

Immediate Management Algorithm

1. Perform excisional biopsy today or within 2 weeks (use urgent cancer pathway if SCC suspected) 2

   • 2-mm margins, longitudinal orientation on forearm
   • Use scalpel under local anesthetic
   • Document excision margins in operative note
   • Send entire specimen to pathologist with patient age, sex, and lesion site

2. Pathology must include 1:

   • Diagnosis and confirmation of malignancy if present
   • Maximum tumor thickness (Breslow depth)
   • Assessment of excision margin completeness
   • Level of invasion (Clark)
   • Presence of ulceration
   • Mitotic rate

3. If histology confirms malignancy:

   • Re-excision with appropriate margins based on tumor type and depth
   • Consider sentinel lymph node biopsy if indicated
   • Refer to dermatology/surgical oncology

4. If histology shows actinic keratosis or benign lesion:

   • Treat appropriately based on specific diagnosis
   • Counsel on sun protection
   • Establish surveillance schedule

Why Waiting is Not Acceptable

The mortality and morbidity implications are significant. Delayed diagnosis of SCC can result in:

• Progression to invasive disease requiring more extensive surgery
• Potential for perineural invasion
• Risk of nodal metastases
• Increased morbidity from larger excisions or need for skin grafting
• Worse cosmetic and functional outcomes

The one-month duration of non-healing already represents a delay. Tissue destruction from inappropriate treatment (cryotherapy, laser, electrocautery) would compromise final diagnosis and assessment of prognostic factors 1.