The Role of Resection of the Outer Table of the Cranium in Locally Invasive Primary Squamous Cell Carcinoma of the Scalp

Abstract

Introduction: Nonmelanoma skin cancer is the most common malignancy of the scalp. Of these, squamous cell carcinoma (SCC) is the most troublesome. It poses a challenge to the surgeons caring for these patients as the anatomy of the scalp makes excision and reconstruction difficult. Although more superficial lesions are amenable to Mohs micrographic surgery, more invasive lesions require a different approach. This manuscript is a retrospective review of outer table resection for SCC of the scalp invading to the depth of the pericranium. We include a discussion of full thickness craniectomy for invasive SCC, regardless of depth of invasion, for completeness.

Methods: IRB approval was obtained from St. Joseph's Hospital and Medical Center in Phoenix, Arizona. One hundred four potential cases identified based on ICD codes. Ultimately, 23 cases met study criteria and were included in this analysis. Seventeen cases of outer table resection and 6 cases of full craniectomy were discussed. Additionally, the authors' approach for resection and reconstruction is articulated.

Results: Seventeen patients underwent outer table resection at an average age of 79.3 years. All had invasion of the pericranium with a mean surface area of 42.6 cm 2 . Eight patients had prior radiation treatment for SCC of the scalp and 12 patients had at least 1 prior surgery to attempt excision of their lesions. Two patients had local recurrence for a local control rate of 88.2% (15/17). One patient with metastasis prior to presentation, died 6 months after his initial surgery for disease-free survival rate of 94.1% (16/17) at a mean of 15.4months. Thirteen patients were able to achieve immediate reconstruction with local flaps with or without additional skin grafting (76.5%).

Discussion: The data in this study supports that in instances of locally invasive primary SCC of the scalp that extends to the pericranium, excision down to the calvarium with complete circumferential and deep peripheral margin assessment, followed by resection of the outer table, is an excellent option. The low rate of local recurrence and high disease-free survival in this study support that this method allows for optimal oncologic outcome while mitigating the significant morbidity associated with the alternative option of a full thickness craniectomy.