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.