Diagnosis:
Core biopsy is often sufficient to reach the pathological diagnosis [48,49]. Cells of a GCTB demonstrate intense positive S-100 staining, and notably stain negative for both progesterone and estrogen [12,28,40]. But sometimes it can be difficult to distinguish malignant from benign GCT on core biopsy and some non-representative biopsies can occur. For instance, when only the skin is sampled in a superficially located GCT this can show pseudoepitheliomatous hyperplasia, which can look like a squamous cell carcinoma. This pseudoepitheliomatous hyperplasia is reactive and found in over half of the GCTs [11]. Benign tumors can also demonstrate both vascular and perineural invasion, but these histologic features do not confer malignancy or an adverse prognosis [50]. Eventually GCT requires complete excisional biopsy since they can have patchy areas of malignancies and a core needle biopsy may not be representative of the entire tumor.