Neurofibromas are benign tumors that are nerve tissue overgrowths along with blood vessels and other types of cells and fibers. Most neurofibromas occur in association with a genetic disorder called neurofibromatosis type 1 (NF-1). This condition can result in multiple neurofibromas and other symptoms. A person with NF-1 may have a few or hundreds of neurofibromas. Solitary neurofibromas can also occur in individuals without NF-1 [1] and are referred to as sporadic neurofibromas (SNFs). The causes are unknown, although researchers have explored the role of trauma. Most SNFs do not cause pain and can be managed without surgery or medications. Cutaneous neurofibromas may grow and multiply with age but typically do not cause significant symptoms other than possible itching and tenderness. However, some are particularly large or in inconvenient locations that cause cosmetic concerns and other issues. In addition, atypical neurofibromas may rarely transform into malignant peripheral nerve sheath tumors [2]. Herein, we present the case of a patient with a particularly large neurofibroma on her elbow that was successfully treated with wide excision and dual superficial circumflex iliac artery perforator (SCIP) flaps. This rare case of reconstruction may provide technical insights for the management of large solitary neurofibromas and extensive dead space obliteration.

A 27-year-old female with an unremarkable medical history presented to our hospital with a large mass in the right elbow. General examination revealed a soft, brownish mass measuring 14×12 cm (Fig. 1). She had normal growth and development, and no family history. She had undergone surgery on her elbow for a painful sensation 12 years prior, but it returned and grew larger. She had six or more café-au-lait spots measuring at least 5 mm before and 15 mm after puberty. The patient presented with axillary freckling and multiple dermal neurofibromas. There were no Lisch nodules on the iris, no optic glioma, no specific skeletal abnormalities such as tibial dysplasia nor abnormality of the orbit. After gene mutation testing, she was diagnosed with NF-1. As the regrown mass accounted for 80% of the total right elbow circumference, surgery was planned to remove the large solitary neurofibroma. Preoperative markings included the anterior superior iliac spine (ASIS), inguinal ligament, and femoral artery. Under general anesthesia, the patient was placed in a supine position throughout the procedure, and the large neurofibroma, including the deep fascia, was completely excised. The size of the soft tissue defect after excision was 12×18 cm. We explored the right posterior radial collateral artery and the vena comitans on the right side, including the radial recurrent artery and venae comitantes recipient vessels (Fig. 2). A dual-free superficial circumflex iliac artery perforator flap was designed from both groin areas. The location of the dominant perforator was determined using intraoperative indocyanine green (ICG) angiography, which scanned the course between the origin of the superficial circumflex iliac artery and the ASIS. Considering the defect size and the dominant perforator, the flaps were designed, with each flap measuring 8×16 cm. Once the perforator and cutaneous veins were identified, further vessel dissection was performed until the required pedicle length was obtained. The flap was then raised in the anterograde direction based on the superficial perforator following the suprafascial plane (Fig. 3). After elevating the bilateral SCIP flaps, we performed a microanatomy between the right superficial circumflex iliac vessels and the right radial artery recurrent branch with the venae comitantes in an end-to-end manner (Fig. 4). The left superficial circumflex vessels were anastomosed to the distal end of the right posterior radial collateral artery with the venae comitantes. The flap was inserted over the defect area with a silastic drain (Fig. 5). After surgery, histologic findings showed a 14×12×1.5 cm-sized plexiform neurofibroma (PN) with mild to moderate cellularity, mild nuclear pleomorphism, and <1/10 high-power field mitosis (Fig. 6). Both flaps survived well with no significant adverse events. The donor sites on both sides also healed well without any complications. During 18 months of follow-up, the patient showed good contour and color matching with no evidence of recurrence, painful sensation, or functional deficit (Fig. 7).

Written informed consent was obtained from the patient for the publication of this report including all clinical images.

PNs can occur anywhere in the body and are inherent in the name, “plexiform,” which means they affect a nerve plexus, a network of large and small nerves that serve a specific part of the body. However, these rare tumors can also affect other tissue types such as muscles and connective tissues. PNs growing in the skin (diffuse PNs) can become large enough to cause the skin and underlying tissue to bulge, resulting in deformities [2]. These tumors occasionally affect the head and face. PNs affecting large nerves exiting the spine, such as the sciatic nerve, are known as nodular PNs. Not always visible to the naked eye; on imaging scans, they can appear as thickened areas of the nerve. PNs are associated with NF-1 and can be present at birth, although they are difficult to detect in young individuals. Most PNs are harmless, but some can grow to be very large, placing pressure on the nerves and organs, and causing pain and weakness. Although benign, PNs can become cancerous and should be closely monitored by physicians. Malignant peripheral nerve sheath tumors arise in approximately 5% to 10% of NF-1 patients, mostly in the plexiform or localized intraneural variant of neurofibroma and are thought to usually take years to develop [2,3].

The mainstay of treatment is en bloc surgical resection of the surrounding fat and muscle fascia, with at least two centimeters of margin [4]. Consequently, reconstruction of a rather large defect is often required. For the thigh region, various options for volume restoration are available, such as deep inferior epigastric perforator, anterolateral thigh flap, thoracodorsal artery perforator, and SCIP flaps. The latter is an extremely versatile solution, as SCIP flaps are relatively simple and quick to harvest, and the thickness and extension can be tailored according to needs. It is pliable, the donor site morbidity is low, and the aesthetic result is good, with a remaining scar that is easy to hide [5]. The ICG examination is an extremely useful tool in all the steps of the SCIP flap procedure. It can be used intraoperatively to map the perforator pathways in the flap region and can also be used intraoperatively to check the perfusion of the flap, before the harvest and after the anastomosis.

SCIP flaps offer numerous advantages in clinical practice. A thin flap can be obtained once the pedicle is visualized and allows for the discarding of deeper tissues. This avoided flap defatting during the primary procedure. Furthermore, raising an adipofascial flap based on a perforator that runs deep into the fascia of Scarpa is ideal for resurfacing large skin defects. In the present case, the flap was raised in the nonhair-bearing region of the skin above the inguinal ligament. This not only allowed us to dissect a thin flap but also enabled us to close the donor site of large flaps by recruiting abdominal tissue [6]. One of the disadvantages of the SCIP flap is that in small flaps, particularly for placement on the digit of a child, the vessel caliber is small and therefore poses a greater challenge in microsurgery. However, over the last decade, refinements in the equipment and techniques have made a positive difference. There is a higher incidence of venous congestion, particularly with small free flaps. Therefore, it is essential that an additional cutaneous vein is taken in these flaps to limit the chances of venous congestion and hence flap failure [7,8].

In conclusion, malignant changes in NF-1 are extremely rare; however, complete excision with adequate flap coverage is necessary for patient safety. The dual SCIP flap in this case was less bulky and had excellent cosmetic results for the large elbow skin defects, while providing an inconspicuous donor scar. Similar to other studies, we recommend the use of the SCIP flap for elbow reconstruction due to its versatility.