Significance of Basal Cell Carcinomas Exhibiting Intravascular Invasion.

ABSTRACT: Intravascular invasion of tumor cells can be associated with metastasis in many cancers. Basal cell carcinomas (BCCs), however, rarely metastasize; therefore, the clinical impact of intravascularly invasive BCC (IVBCC) is currently unclear. Because of these facts and the rarity of IVBCC, questions have arisen on whether IVBCC truly exists. We present 4 cases of IVBCC: one case with obvious tumor islands within immunolabeled blood vessels in the context of advanced disease and 3 cases found incidentally during Mohs micrographic surgery. We discuss the difficulty in studying IVBCC, the idea that it could be due to artifact, and the lack of direct clinical-pathological correlation. Given these challenges, we propose diagnostic criteria for IVBCC to decrease ambiguity for pathological diagnosis. Such criteria may facilitate further studies on the clinical significance of IVBCC.

Diagnostic utility of cytokeratin 17 immunostaining in morpheaform basal cell carcinoma and for facilitating the detection of tumor cells at the surgical margins.

BACKGROUND: The morpheaform subtype of basal cell carcinoma (BCC) often presents a diagnostic histological challenge, and its true margin may be difficult to determine with accuracy. This tumor may also be difficult to distinguish from other adnexal neoplasms having a benign clinical course. Previous work has shown that cytokeratin 17 (CK17 or K17) expression is high in BCC. OBJECTIVE: To confirm the expression of K17 across the subtypes of superficial, nodular and morpheaform BCC variants and to compare K17 expression in each of these subtypes of BCC with that in two other adnexal neoplasms. METHODS: Tissue specimens from each tumor category were randomly collected, immunolabeled, and scored for K17 expression according to intensity and extent of immunostaining. RESULTS: Our results indicate that K17 is a useful marker in the identification and outlining of BCC. Moreover, in morpheaform BCC, K17 immunostaining clearly detected individual tumor cells well away from the dermal tumor strands that otherwise seemed nonmalignant according to hematoxylin and eosin staining alone. In addition, the expression of K17 in morpheaform BCC is capable (100% of specimens; p < .001) of distinguishing this tumor from desmoplastic trichoepithelioma. CONCLUSION: We propose that K17 immunostaining could improve the diagnostic and surgical management of these tumors.