Track

Clinical Studies

Abstract

Primary cutaneous carcinosarcomas (PCCS) are rare neoplasms of the skin composed of malignant epithelial (carcinomatous) and mesenchymal (sarcomatous) components. PCCS, in general have more aggressive behavior compared to primary cutaneous keratinocytic carcinomas and surgical resection is the primary management for these tumors. While PD1/PD-L1 blockade therapy has been approved by the FDA for management of advanced and/or metastatic squamous and basal cell carcinomas (SCC and BCC), there are currently no standardized systemic therapies for PCCS, mainly due to their rarity. In this study, we evaluated the prevalence of PD-L1 expression in a series of 15 PCCS cases. Our cohort includes 13 men and 2 women with a median age of 78 years. Most of the tumors were located in sun-exposed skin of the head & neck (n=10) and extremities (upper n=4; lower n=1). The tumors were composed most commonly of SCC (n=9, most were poorly-differentiated, 6/9), followed by BCC (n=4) and adnexal carcinoma (n=2). An undifferentiated pleomorphic sarcomatous component was present in all cases.  Representative sections containing both carcinomatous and sarcomatous components were stained using the 22C3 PD-L1 clone and the Tumor Proportion Score (TPS) was assessed based on the percentage of tumoral membranous labeling of any intensity in both components. PD-L1 expression ranged from <1% (n=9) to 1-10% (n=3) and >10% (n=3). In summary, PD-L1 expression in a subset of PCCS cases suggests that immune checkpoint inhibitors may be considered in at least some patients for the management of advanced or unresectable PCCS.