Differential Diagnosis, Investigations and Treatment
In this case, diagnosis is difficult. Squamous cell carcinoma of the jaw
was considered at first impression because the swelling, pain and
numbness in the left mandible for more than 4 years. However, according
to the imaging results, the lesion developed along the mandibular canal
with clear boundaries, so we believed that the lesion was a neurogenic
tumor with high probability of benign. In maxillofacial region, the most
common neurogenic tumors are schwannoma and neurofibroma. But the
clinical and imaging findings of this case did not support these two
diagnoses. To determine the nature of the lesion, we performed a
fine-needle aspiration biopsy, but the puncture was not successful, so
we decided to proceed directly to exploratory excision.
The tumor was totally excised under general anesthesia. During the
operation, the tumor was noted along the long axis of the inferior
alveolar nerve; appeared white; and had an intact capsule, cystic
cavity, and milky cloudy fluid; the inferior alveolar nerve had
denatured and could not be distinguished from the mass (Figure 5). The
tumor and the adjacent nerve were completely excised during the
operation.
Intraoperative frozen sections were obtained for pathological
examination. The pathological examination indicated a cystic wall
composed of fibrous connective tissue aggregated with a large number of
histiocytic and cytoplasm-rich cells (Figure 6). Postoperative
immunohistochemical pathology results showed cytokeratin (CK) (-), CD68
(focal +), CD163 (focal +), Ki-67 (+ <2%), S-100 (+), CD56 (+),
synaptophysin (Syn) (-/+), SRY-related HMG-box (SOX)-10 (+),
neuron-specific enolase (NSE) (-/+), glial fibrillary acidic protein
(GFAP) (-), neurofilament (NF) (partial +), and ETS-related gene (ERG)
(-) (Figure 7). Immunohistochemical analysis showed the GCT with
slightly irregular nuclei surrounded by a few nerve fibers.