What You Should Know About Potentially Malignant Wounds

Clinical Editor: Lawrence Karlock, DPM

A: As Dr. Bakotic says, the likelihood of amputation varies widely, depending on the neoplasm’s biology, the affected location and the patient’s level of activity, vascular status and overall health status. Since even the excision of small malignancies of the toes will lead to “monumental problems” with closure, he advises that patients in poor health or those who are inactive will typically fare much better with digital amputation. Younger or largely healthy people are more likely to tolerate plastic procedures, graft placement or healing by secondary intention when it comes to excising carcinomas or in-situ melanomas of the digits, according to Dr. Bakotic. Drs. Goss and Minhas say amputation is a consideration when the patient requires an optimal functional outcome, especially in terms of his or her goals for rehabilitation. For example, they note that large, destructive tumors of the digits may need a distal Symes amputation.
Drs. Goss and Minhas note that aggressive lesions of the forefoot may require either partial ray or transmetatarsal amputation whereas such tumors in the rearfoot usually require a below-the-knee amputation. They concur that most synovial sarcomas and fibrosarcomas usually necessitate amputation as definitive treatment.
In most cases, Dr. Bakotic says thin invasive melanomas of the digits will warrant amputation at the interphalangeal joint and invasive melanomas of greater than 1 mm in thickness will result in amputation at the metatarsophalangeal joint (MPJ). He says amputations proximal to the digits are rarely indicated for tumors of the skin. Dr. Bakotic notes that physicians should reserve proximal amputations for sarcomas of the deep soft tissue that are unlikely to be confused with non-neoplastic ulcerations.
If he finds a malignant wound, Dr. Morse usually consults an oncologist. If an excision is inadequate, he says amputation is the next step. He adds that this requires a certain bedside manner in order to explain the nature of the problem to the patient.

Q: Do you have any insight on nail bed wounds that have a malignant potential?

A: “If there is inadequate healing of a wound, you must biopsy,” emphasizes Dr. Morse. “No matter how many nail bed wounds you have seen, you cannot tell the malignant ones from the benign ones by looking at them. You must biopsy these wounds. If you are concerned about the biopsy, send it to another doctor for a consultation.”
Dr. Bakotic notes the complicating feature in this location is the presence of an overlying nail plate that may or may not be dystrophic. As a result of the anatomy in this location, “wounds” of the nail unit often clinically resemble a subungual hematoma or periungual ecchymosis, according to Dr. Bakotic. Unfortunately, he says such a clinical appearance serves as a diagnostic pitfall and is further complicated by the fact that many of these patients offer a clinical history that includes localized trauma. He estimates that nearly 90 percent of the nail unit melanomas he sees in practice are associated with a false history of “trauma.”
Additionally, Dr. Bakotic notes a little known fact that nail unit malignancies that arise within the matrix (melanoma and some squamous cell carcinomas) can distort nail growth, resulting in a dystrophic nail that may be identical to that created in association with microtrauma or onychomycosis. Since melanoma of the nail unit typically arises within the nail matrix, he says amelanotic lesions are commonly associated with this phenomenon.
For Drs. Goss and Minhas, wounds that begin under the nail and extend outward onto healthy peri-nail skin (Hutchinson’s sign) are a concern due to the possibility of subungual (malignant) melanoma. Amelanotic melanomas of the nail bed often resemble chronic paronychias. Both doctors concur that malignant wounds may form rapidly or may be longstanding nail bed ulcers such as squamous cell ulcers that do not show signs of improvement. They note that such lesions may also appear as ingrown toenails that do not seem to improve no matter what the treatment. While rare, metastases from other primary tumors may develop under the nail as well, according to Drs. Goss and Minhas.

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