What happens if melanoma is mistaken for a benign condition and treated with cryotherapy (cryo) or laser?

Consequences of Misdiagnosing Melanoma as Benign and Treating with Cryotherapy or Laser

If melanoma is mistaken for a benign lesion and treated with cryotherapy or laser, the primary consequence is destruction of tissue that prevents accurate histopathological diagnosis and staging, which are absolutely essential for determining appropriate definitive treatment and prognosis. 1

Critical Diagnostic Failure

The fundamental problem is that tissue destruction from cryotherapy or laser ablation eliminates the ability to perform histopathological examination, which is mandatory for all excised cutaneous lesions. 1 This creates several cascading problems:

• Loss of Breslow thickness measurement: The single most important prognostic factor in melanoma cannot be determined without intact tissue, making it impossible to plan appropriate surgical margins (which range from 0.5 cm for melanoma in situ to 2 cm for lesions >2 mm thick). 1

• Cannot assess ulceration or mitotic rate: These are critical AJCC staging parameters that directly impact prognosis and treatment decisions, including whether sentinel lymph node biopsy is indicated. 1, 2

• Inability to confirm diagnosis: Without histopathology, you cannot definitively confirm melanoma versus a benign lesion, leaving the patient in diagnostic limbo. 1

Clinical Management After Tissue Destruction

When faced with this scenario, the approach must be aggressive given the uncertainty:

• Wide re-excision is mandatory: Even without knowing the exact Breslow thickness, the area must be widely excised with at least 1-2 cm margins to ensure any residual melanoma is removed. 1

• Consider sentinel lymph node biopsy: Given the diagnostic uncertainty and potential for understaging, sentinel node biopsy should be strongly considered, as you must assume the lesion could have been thick enough to warrant nodal staging. 1

• Expert dermatopathology review of any available tissue: If any tissue fragments remain (even from cryotherapy), they should be sent for expert pathology review, though this is often inadequate. 1

Why Scalpel Excision is Non-Negotiable

The guidelines are explicit that tissue should be removed using a scalpel rather than laser or electrocautery to preserve histological features. 1, 3 This is not merely a preference—it is a standard of care because:

• Thermal destruction from laser or cryotherapy causes tissue artifact that makes microscopic evaluation impossible or unreliable. 1
• Complete histological examination of the entire lesion is necessary to assess all prognostic parameters, particularly maximum thickness. 1
• Frozen sections are discouraged for the same reason—they compromise diagnostic accuracy. 1

Medicolegal Implications

Misdiagnosis of melanoma represents one of the most common causes for malpractice litigation against medical practitioners, particularly when destructive techniques are used without prior biopsy. 4 The failure to obtain tissue diagnosis before destructive treatment is considered a significant deviation from standard of care. 1

Impact on Prognosis and Survival

The consequences extend beyond diagnostic uncertainty:

• Delayed definitive treatment: The time lost in recognizing the error and performing appropriate wide excision may allow for disease progression or metastasis. 5, 6

• Potential for local recurrence: Incomplete treatment with cryotherapy or laser leaves viable melanoma cells that can recur locally, and local recurrence is associated with worse prognosis. 1

• Loss of staging accuracy: Without proper staging, you cannot accurately counsel the patient about prognosis or determine appropriate surveillance intervals. 1, 2

Prevention Strategy

To avoid this catastrophic error:

• Never use destructive techniques on any pigmented lesion without histological confirmation of benignity. 1
• Apply ABCDE criteria (Asymmetry, irregular Borders, Color variation, Diameter >6mm, Evolution) to all pigmented lesions before considering any treatment. 1, 2, 7
• When in doubt, perform excisional biopsy with 2-5 mm margins rather than destructive treatment. 1, 2
• All excised tissue must be sent for histopathological examination—this is non-negotiable. 1, 3