Abstract
The majority of physicians treating melanoma in situ recommend a 5mm to 1cm margin with excision into the subcutaneous tissue extending between the superficial and the deep fat. There is always the potential for an unrecognized invasive component in a melanoma in situ, making aqueous zinc chloride solution an ideal agent to treat the excision wound of a melanoma in situ of the trunk and extremities. Zinc chloride solution penetrates deeply and widely, killing and fixing tissue when applied to the excision wound, facilitating the excision by allowing for a simple saucerized excision with a narrower and thinner margin while ensuring the treatment of any possible unrecognized invasive components. Zinc chloride has been used in a paste since 1835 to treat skin cancers and melanoma but unlike pastes zinc chloride in solution is recognized by the U.S. Food & Drug Administration as a generally safe substance (Code of Federal Regulations Title 21 [Part 182]). The solution penetrates as deeply and widely and effectively as in the paste which Mohs described to be an inactive vehicle for the active ingredient, zinc chloride solution. Mohs reported a large significant survival benefit (p=0.003) for invasive melanoma using surgery combined with zinc chloride over conventional melanoma surgery. Zinc chloride solution without the paste is a new medicine effective as a surgical adjuvant in the treatment of the excision wound of a melanoma in situ of the trunk and extremities. Zinc chloride can be used as a surgical adjuvant for any melanoma, but melanoma in situ of the trunk and extremities is the logical starting point for a physician interested in using this adjuvant in the treatment of melanoma. Zinc chloride is very powerful and potentially scarring and should be used on the excision wound of a previously histologically diagnosed melanoma only.