3. Discussion
Herein, we reported a case of plexiform schwannoma with an unusual size
that developing in an unusual location. Generally, Schwann cell tumors
are categorized as neurofibromas, schwannomas, and malignant peripheral
nerve sheath tumors (MPNSTs). In addition, these tumors can be
considered as a manifestation of genetic diseases, such as
Neurofibromatosis type 2 (NF-2), carney complex type 1, and
schwannomatosis (5).
Schwannoma is considered a benign peripheral nerve sheath tumor that
stems from the slow proliferation of Schwann cells (2). The plexiform
schwannomas are benign tumors, which develops in a plexiform pattern;
nevertheless, the malignant transformation is rarely reported (5).
Clinically, this tumor often develops as a solitary subcutaneous or
intradermal nodule and grows in a small size, the greatest diameter of
which is mostly lower than 2 cm (6). Imaging particularly MRI can be
helpful in diagnosis and localization of the lesion before the
treatment; however, the diagnosis cannot be confirmed without
histopathological studies (7).
From the histopathological view, various nodules which locate
intradermally or subcutaneously consist of cellular Antoni A, in which
areas with both nuclear palisading and verocay bodies are detected. In
contrast to schwannomas, plexiform schwannomas develop in a plexiform
configuration including various interconnecting nodules and fascicles in
Antoni A areas (8). Plexiform neurofibroma could be considered as a
differential diagnosis of plexiform schwannoma from a histological
aspect. However, plexiform schwannomas are made of Schwann cells which
can be detected via S100 protein staining (9).