Figure 1. (A, B) Histopathological slides from cyst wall curettage. The image shows multiple fragments of fibro-collagenous tissue infiltrated by malignant squamous cells arranged in trabeculae, nests, and singly distributed surrounded by desmoplastic stroma. The malignant cells are enlarged, polygonal, and moderately to markedly pleomorphic, displaying hyperchromatic nuclei, some with prominent nucleoli and ample eosinophilic cytoplasm. Mitosis is frequently seen. Dyskeratotic cells and focal intercellular bridges are present. No keratin pearl formation was noted. No lymphovascular invasion was seen. The background shows blood and some foamy macrophages. Hematoxylin & Eosin (H&E): 200× and 400× magnification. (C, D) The malignant cells are positive for squamous markers: (C) strong membrane/cytoplasmic staining for CK5/6, and (D) mild to moderate nuclear staining for the p63 tumor protein (400X magnification).