2. Case presentation
A 33 years-old male patient was referred to our dermatology clinic due to the growing soft tissue mass on his foot. Initially, the mass appeared on his second toe of the right foot 20 years ago. Recently he has noted a progressive growth in the bulk for the last 6 months. He denied any significant past medical history or drug history. He also did not mention any relevant familial history, as well.
In the physical examination, there was a non-tender erythematous nodule on the phalanx of his second right toe. The nodule was immobile and measured 3 cm in diameter (Figure 1). No similar lesions were observed on any other parts of his body. Accordingly, X-ray imaging confirmed that the nodule was arising with the soft tissue and no bone involvement was detected.
Punch biopsy was taken from the nodule while considering myxoid cyst, neuromas, and giant cell tumor of tendon sheath as the differential diagnoses. Microscopic examination revealed a portion of plexiform neoplasm in the dermis composed of multiple nodules of proliferated spindle cells with wavy nuclei in a fibrillary matrix. There were areas of nuclear palisading forming verocay body appearance of intervening stroma between the nodules composed of a loose meshwork of spindle cells with microcystic change and scattered inflammatory cells (Figure 2). In addition, immunostaining was performed for S-100 and Epithelial Membrane Antigen (EMA) and reported positive and negative, respectively (Figure3). These histopathology features were in favor of plexiform schwannoma. Finally, the patient was referred to an orthopedic surgeon in order to excise the lesion precisely.