Useful techniques for the resection of foot melanomas

The prevalence of melanoma is rapidly increasing[1,2] and therefore more patients are being evaluated bysurgeons for treatment of this tumor. A main componentof the treatment of primary melanoma involves wide lo-cal excision (WLE) of the primary lesion or of the biopsyscar with adequate margins [1–8]. Although this mayseem to be a simple task on certain areas of the body,such as the back, chest, abdomen, and proximal extrem-ity, it can prove difficult to do on the foot while stillmaintaining adequate function and providing coverage.Since acral (distal extremity) melanomas account for 4%to 35% [2–5,7,8] of all cutaneous malignant melanomasdepending on the population, we present useful tech-niques which provide excellent functional results in treat-ing these difficult lesions.Because foot melanomas can be found on any surfaceof the foot, the foot should be thoroughly inspected aspart of any skin examination. We have divided the footinto different anatomic regions as shown in Figure 1.Among the 2,439 cases of invasive melanomas compiledin a database established by the University of MichiganMultidisciplinary Melanoma Clinic, 63 (2.6%) were lo-cated on the foot (ankle lesions were excluded). Theanatomic distribution and thickness of 57 of those casesare summarized in Table I (Breslow depth of the remain-ing 6 cases were unknown). As with other areas of thebody, these lesions should undergo WLE with marginsthat are adequate for the histologic depth of the tumor. Ifthe lesion is thin, and is located in a favorable locationsuch as at the dorsum of the foot where there is some skinlaxity, then a WLE and primary closure can be per-formed. However, acral lesions are generally thicker thanlesions found elsewhere on the body [1,4]. Often, thealternate methods described below are required to obtainan optimal result.MATERIALS AND METHODSToe LesionsToe lesions can occur in the subungual area [9,10] orskin overlying the digit and/or web space. Toe melano-mas proved to be the thickest lesions in our experience(Table I), with the thickest being the subungual melano-mas. For subungual and digital skin lesions, a ray ampu-tation is appropriate for wide excision. Amputations ofthe great toe should always attempt to leave the metatar-sal head intact in order to allow more even distribution ofweight bearing, which results in better balance. This canbe accomplished with a primary skin closure, but oftennecessitates creating a skin flap. Depending on the loca-tion of the lesion on the great toe (i.e., subungual or skin),a skin flap can be fashioned from the toe skin furthestaway from the lesion in order to achieve coverage (Fig.2). For the remaining digits, the ray amputation shouldentail removal of the metatarsal head in order to allow fortension-free primary skin closure and improved cosmesis(see case 4).Lesions of the toe web space requires amputation ofmore than one digit. As illustrated in case 1 (Fig. 3), this74-year-old woman presented with a melanoma of 2.6mm in Breslow depth in the web spaces of the third andfourth toes, as well as the fourth and fifth toes. Thisnecessitated amputation of the third, fourth, and fifth toesto include the metatarsal heads for closure. Postopera-tively she maintains a normal gait and does not requireany special shoe. At her last follow-up 3.5 years from herresection, she continues to remain free of disease. Forthese lesions, we recommend ray amputation of both dig-