INTRODUCTION
The advantages of the Mohs technique are well documented;
it allows for complete micrographic margin control,the pathology is interpreted by the surgeon himself, and thus it is more accurate and saves time and money. The defect
created after the excision of the lesion is smaller, allowing for easier closure, and, if needed, immediate reconstruction.1,2 It has also been shown that Mohs technique for skin lesions is more
cost-effective in the U.S. than conventional surgical excision.3
Mohs is considered a skin-sparing technique, as compared to conventional surgical excision,4-6 but is it a truly skin-sparing surgery in all cases? Unlike breast cancer skin-sparing operations, for example, where the breast is resected while the skin envelope is preserved, in Mohs surgery the skin is excised in some instances even if it is not involved with tumor cells, just to get to a deeper layer (fascia, muscle) were tumor is still present. Still, in most cases, the immediate pathological information gathered by the surgeon allows for the surgical defect to remain as small as possible while still keeping good margin control.7
Every Mohs surgeon, during his years of practice, encounters skin tumors that look rather innocuous and small on the surface but extend over long distances under the skin surface. The excision of these seemingly small lesions can sometimes result in a large skin defect. This type of tumor typically appears on the forehead and scalp where the tumor, usually a morphea type BCC, finds its way to the loose areolar tissue, galea, or temporal fascia and spreads for long distances under the surface, requiring a multi-stage Mohs
surgery. The dermis looks normal and in fact is not involved by the tumor, hence every new stage involves scarifying normal skin in order to get to the underlying tumor. A significantly smaller defect could have resulted if the tumor had been safely removed under the surface while maintaining the normal skin above.
We would like to suggest a new technique demonstrating ow to safely extirpate such tumors while preserving the uninvolved overlying skin.
Technique
A 72-year-old male underwent a frozen section controlled extirpation of a morphea type BCC on the left side of his forehead nine years before arriving at our clinic. The post-operative defect was down to the bone and included almost all of the left half of the forehead. It was reconstructed with a radial forearm free flap. This was done under general anesthesia by a plastic surgeon, lasted nine hours and required a 12-day hospitalization. When he came to our Mohs clinic for a small BCC removal in a different location, a subcutaneous mass was noticed on the lateral border of the old free flap and a biopsy was taken. The biopsy revealed a recurrent BCC and the patient was scheduled for Mohs surgery. Upon surgery, the tumor was not yet cleared out after eight stages (Figure 1).
A 72-year-old male underwent a frozen section controlled extirpation of a morphea type BCC on the left side of his forehead nine years before arriving at our clinic. The post-operative defect was down to the bone and included almost all of the left half of the forehead. It was reconstructed with a radial forearm free flap. This was done under general anesthesia by a plastic surgeon, lasted nine hours and required a 12-day hospitalization. When he came to our Mohs clinic for a small BCC removal in a different location, a subcutaneous mass was noticed on the lateral border of the old free flap and a biopsy was taken. The biopsy revealed a recurrent BCC and the patient was scheduled for Mohs surgery. Upon surgery, the tumor was not yet cleared out after eight stages (Figure 1).
The surgery was halted at this stage and the patient was scheduled for another surgical session two days later. On the ninth stage of Mohs resection, the tumor was microscopically tracked spreading along the deep temporal fascia at segments number 4 and 5 (Figure 2, map 9), while the overlying skin was uninvolved. This inflicted great frustration on the surgeon, who was forced to sacrifice normal hair-bearing skin while watching a growing defect on his patient's face.
