Table 3.

Differential histopathological diagnosis.

Type of the tumor	Description
Lymphoepithelial carcinoma- Undifferentiated/Schmincke's tumor	•Lesion is microscopically characterized by tumor cells with spindle-to-oval hyperchromatic or vesicular nuclei bearing prominent nucleoli, which feature scattered mitotic activity; •Variable numbers of intermixed lymphocytes and plasma cells; Two classically described tumor growth patterns: – The “Regaud” pattern with a solid sheet-like tumor cell growth pattern, – The “Schmincke” presenting separated or loosely attached tumor cells (described as a reticulated pattern) with prominent intermixed lymphocytes •Cytokeratin-positive cells Stick in groups or in a reticulated pattern mixed with lymphocytes
Lymphoma	•Tumor can be difficult to differentiate from carcinoma on morphological features alone; •Tumor cells form cohesive groups and have ill-defined cell borders; •An immunohistochemistry panel (LCA and cytokeratin) has great value in the diagnosis
Melanoma	•Three histological types: epithelioid, spindled, or undifferentiated; •Presence of melanin pigment; •Multinucleate lesion; •Giant cells present; •Positivity for S-100, HMB-45, melan-A