Optimal Time for Nevus Sebaceous Excision and Predictors of Surgical Outcomes and Secondary Intralesional Neoplasms: The Mayo Clinic Experience Over 37 Years
Background: Controversy exists around the optimal timing of resection of nevus sebaceous (NS). The authors aim to determine optimal timing of NS resection and identify predictors of surgical outcomes and secondary intralesional neoplasms. Methods: Retrospective chart review of all patients with biopsy-proven NS diagnosis treated at the authors' institution between 1987 and 2024. Results: A total of 632 patients (317 females) underwent biopsy at a median age of 17 (interquartile range 11.7–36.9) years. Benign secondary intralesional neoplasms were found in 67 (10.6%) patients, with syringocystadenoma papilliferum being the most common. Malignant secondary intralesional neoplasms were diagnosed in 62 (9.8%) patients, with basal cell carcinoma being the most common. The incidence of secondary intralesional neoplasms was 3.9%, 24.4%, 36.05%, and 54%, in patients aged 0 to 20, 20 to 40, 40 to 60, and 60 to 80 years, respectively (P<0.001). Age and NS area were associated with an increased risk of developing benign and malignant intralesional neoplasms (P=0.01). Younger patients were more likely to need general anesthesia for excision (median age 10.42 versus 17 years, P<0.001). Surgical complications occurred in 10 cases, and 6 patients required unanticipated revision surgery. The risk of developing secondary intralesional neoplasms was similar across different NS anatomic regions (log-rank, P=0.09). Conclusion: Surgical excision of NS is safe and has an acceptable risk profile. The findings of this study support our historic practice of NS excision before puberty (before the accelerated growth phase) to reduce the risk of developing secondary intralesional neoplasms.
The Fate of the Frozen Bone Flap: Quantitative and Volumetric Assessment Following Cranioplasty Using the Autologous Bone Flap
Objective: The pattern, rate, and natural history of bone flap resorption following cranioplasty with frozen, autologous bone flap has not been fully defined. The authors sought to quantify the progression and natural history of bone flap resorption. Methods: Patients who had craniectomy and delayed cranioplasty with stored, frozen bone flap between 2012 and 2022 were included in this study. Results: Ninety patients (63% male) were included, with a median age of 44.8 years (range: 4.2–84.4 y) at the time of autologous bone flap cranioplasty. Delayed, autologous cranioplasty occurred at a median time of 29.5 days (range: 2 d–10 y) from the index craniectomy. The median follow-up was 16.6 months (range: 3.4–85.4 mo). Radiographically quantifiable bone flap resorption occurred in 50 patients (56%). During the follow-up, the average percentage volume loss was 17%, with a nonlinear pattern of resorption. Following delayed, autologous cranioplasty, 11 patients had clinically significant bone flap resorption requiring secondary alloplastic cranioplasty at a median time of 13.8 months (range: 5.9–57.2 mo), with a mean percentage volume loss of 61%. Younger age was a risk factor for bone flap resorption (P < 0.05), whereas active smoking, presence of comorbidities, and number of days of bone flap storage were not risk factors for bone flap resorption. Penalized B-spline regression analysis showed that bone flap resorption followed a nonlinear pattern. Conclusion: Radiographically quantifiable bone flap resorption occurred in about 56% of patients following delayed autologous cranioplasty. Resorption followed a non-linear pattern. Young age is a risk factor for bone flap resorption.
Accuracy of Preoperative Imaging in Assessing the Positivity of the Deep Periosteal Margin in Dermatofibrosarcoma Protuberans of the Scalp
The locally aggressive nature and high recurrence rate of dermatofibrosarcoma protuberans (DFSP) make it challenging to manage, especially when present on the scalp, owing to its ability to invade the underlying periosteum, bone, dura, or brain. Preoperative imaging is used to plan resection, but the true correlation between periosteal or osseous changes on imaging and the presence of tumor within the periosteum is unclear. We present our institutional experience of managing DFSP of the scalp with emphasis on the imaging used. A retrospective review of 33 patients with DFSP of the scalp treated at a tertiary center was conducted. Data on demographics, tumor characteristics, preoperative imaging (magnetic resonance imaging or computed tomography), and surgical outcomes were analyzed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging modality were calculated. Patients underwent surgical resection at a mean age of 37.11 years and had a median follow-up of 28.34 months. Preoperative imaging was available for 26 patients (CT only: 5, MRI only: 12, CT and MRI: 9). Calvarial abnormalities were seen in 3 patients. Treatment included Mohs surgery (66.7%) and wide local excision (33.3%). In 10 patients with positive periosteal margins, bone involvement was managed by burring (7) or craniectomy (3). The sensitivity and PPV of CT for periosteal margin positivity were 25% and 100%, and for MRI were 33% and 100%, respectively. The specificity and NPV were 100% and 50% for CT, and 100% and 66% for MRI. Preoperative CT and MRI have low sensitivity and NPV but high specificity and PPV in determining depth of involvement and are essential to guiding reconstruction in DFSP of the scalp.
D19. Accuracy of Preoperative Imaging in Assessing the Involvement of the Deep Periosteal Margin in Dermatofibrosarcoma Protuberans of the Scalp: The Mayo Clinic Experience
53. Accuracy Of Preoperative Imaging In Assessing The Involvement Of The Deep Periosteal Margin In Dermatofibrosarcoma Protuberans Of The Scalp: The Mayo Clinic Experience
Summary: After a transnasal endoscopic resection of a high-grade adenoid cystic carcinoma that underwent adjuvant chemoradiation, there was delayed recurrence managed by en bloc resection through an open craniofacial approach. Subsequently, the patient developed a chronic nasocranial fistula with secondary infection and bone flap resorption. This resulted in infectious episodes with secondary scalp incisional dehiscence and hardware exposure which required multiple bone debridement procedures, hardware removal, prolonged IV antibiotics, and hyperbaric oxygen treatment. The nasocranial fistula and chronic frontal bone osteomyelitis persisted despite the previous interventions. The patient underwent a frontal bone removal and obliteration of the anterior cranial base fistula with a free vastus lateralis muscle flap. At 4 weeks postoperatively, the intranasal portion of the muscle flap had completely mucosalized. After a 6-week course of IV antibiotics, a secondary cranioplasty using a custom-made poly-ether-ether-ketone implant was performed. The patient remained disease- and infection-free for the duration of follow-up (17 months).
Use of the Intercostal Artery-based Latissimus Dorsi Muscle for Intrathoracic Reconstruction after Division of the Thoracodorsal Vessels and Latissimus Dorsi Muscle
Summary: The latissimus dorsi muscle is the workhorse flap for intrathoracic reconstruction. Prior thoracotomy, which divides the latissimus dorsi muscle, limits the muscle’s intrathoracic reach. We present our experience using the distal portion of the muscle for intrathoracic reconstruction based off an intercostal vessel. We also demonstrate the ability of this intercostal perforator to allow for chimeric flap elevation with a separate skin paddle, depending on the branching pattern of the intercostal vessels. This study provides a case series of three consecutive patients, treated between September 2021 and June 2022. The intrathoracic pathology addressed in these patients are bronchopleural fistula, aortoesophageal fistula, and bronchoesophageal fistula. All patients had the resolution of symptoms related to intrathoracic fistulae and did not experience recurrence. This novel pedicled muscle flap can be an additional option for patients with prior thoracotomy and avoids the morbidity which can be seen with the serratus or rectus abdominis muscle flaps.