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.