Clear cell sarcoma in unusual sites mimicking metastatic melanoma

Figure 1 Histopathology of the submandibular gland mass in Case 1. A: Section of the mass showed nests of poorly differentiated tumor cells infiltrating into the benign acinic cells (HE,× 50); B: Neoplastic cells displayed pleomorphic, bizarre nuclei with prominent nucleoli and mitotic figures (HE,× 400). HE: Hematoxylin and eosin.

Figure 2 Immunohistochemistry of the submandibular mass in Case 1. A-C: The tumor cells demonstrated positive staining for (A) Human Melanoma Black-45 (× 400) and (B) S-100 (× 400) and negative staining in neoplastic cells for (C) keratin (× 400); D: The melanin pigment in the tumor cells showed positive reaction to Masson Fontana stain (× 400).

Figure 3 Radiology and pathology of the thoracic paraspinal mass in Case 2. A: Magnetic resonance imaging of the tumor showed an enhancing thoracic spine mass involving the paraspinal soft tissues; B: Sections of the mass showed fascicles and nests of spindle cells (HE, × 50); C, D: Neoplastic cells displayed melanin pigments (HE, × 400) and positivity for Human Melanoma Black-45 by immunohistochemistry (× 400). HE: Hematoxylin and eosin.

Figure 4 Fluorescence in situ hybridization analysis of the spinal tumor in Case 2. Fluorescence in situ hybridization using a dual-color, break-apart probe for EWSR1 demonstrated one normal fusion (yellow) along with an extra red signal and extra green signal, indicating translocation.