A Rare Case of Solitary Neurofibroma Misdiagnosed as Diabetic Foot Ulcer in the Toe Tip Region

Abstract

Neurofibromas, rare benign tumors of the peripheral nerve sheath, present diagnostic challenges, particularly in diabetic patients with toe ulcers. This case involves a 55-year-old female with type 2 diabetes mellitus who developed an enlarging ulcer on her right second toe. The initial evaluation suggested a diabetic ulcer; however, advanced imaging revealed a mass-like lesion. Partial excision and biopsy confirmed a neurofibroma with spindle cells within the myxoid stroma and S100 protein expression. One month later, total excision and Z-plasty reconstruction were performed under general anesthesia. The patient's postoperative recovery was uneventful, and the patient was discharged without complications. Follow-up revealed successful healing with no recurrence or functional issues. This case highlights the importance of considering neurofibromas in the differential diagnosis of diabetic toe ulcers to avoid misdiagnosis and ensure appropriate management.

Keywords: case reports; diabetes mellitus; diabetic; foot ulcer; neurofibroma; type 2.

Figure 1

Initial Presentation and Diagnostic Imaging. (A) Clinical photograph of the patient’s right second toe showing an ulcerated lesion on the tip with significant induration and swelling. The ulcer is round, well-circumscribed, and exhibits a red granular base. (B) X-ray image of the right foot demonstrating no specific bony abnormalities associated with the ulcerated lesion. The bony structures of the foot, including the phalanges and metatarsals, appear normal without signs of osteomyelitis or fracture.

Figure 2

Diagnostic Imaging of the Right Second Toe. (A) Lower extremity angio CT showing a mass-like lesion with feeding vessels (red circle), indicating significant vascular involvement in the lesion. (B) MRI finding demonstrating a cystic lesion (yellow circle) at the tip of the right second toe. The MRI shows the extent of the lesion, suggesting a soft tissue tumor rather than a typical diabetic ulcer. The well-demarcated margins and internal characteristics of the lesion are consistent with a neurofibroma. Abbreviations: CT, computed tomography; MRI, magnetic resonance imaging.

Figure 3

Histopathological examination confirmed the presence of neurofibroma, characterized by spindle cells within a myxoid stroma, and showed S-100 protein positivity. (A) Hematoxylin and eosin (H&E) staining at 100x magnification, illustrating the spindle cells within a myxoid stroma. (B) Immunohistochemical staining for S-100 protein at 100x magnification, demonstrating strong positivity in the spindle cells.

Figure 4

Intraoperative Findings and Immediate Postoperative Outcome. (A) Intraoperative finding showing the mass encapsulated by a feeding vessel, which is being meticulously dissected and identified (pink arrow) on the right second toe. (B) The excised mass, displaying a sheath encasing the neurofibroma. (C) Immediate postoperative view of the right second toe demonstrating successful reconstruction using Z-plasty, effectively replicating the original appearance of the toe.

Figure 5

Postoperative Healing and Follow-up. (A) Photograph taken on postoperative day 5 showing a clean surgical site on the right second toe. The patient was discharged without any postoperative complications. (B) Follow-up photograph taken two months postoperatively demonstrating successful healing without recurrence or complications. The toe appears well healed with no signs of infection or other adverse effects.