BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) includes in situ cSCC (Bowen's disease [BD]) and invasive cSCC. By contrast, keratoacanthoma (KA) is a well-differentiated cSCC with self-resolving tendencies. Dermoscopy aids in monitoring vascular and keratin pattern changes to diagnose and track cSCC invasion. OBJECTIVES: To examine dermoscopic findings of cSCC according to histopathological differentiation and clinical morphological characteristics. METHODS: Clinical and dermoscopic images of 118 cSCCs were retrospectively examined. RESULTS: Compared to other cSCC subtypes, BD more frequently presented with pigmentation (p = 0.028) and a clustered (p = 0.042) or serpiginous (p = 0.006) vascular arrangement. Central keratin plugs were more common in well-differentiated invasive cSCCs (p = 0.021), while white circles surrounding follicles (p <
0.001), ulceration/bleeding (p = 0.001), and red background (p = 0.004) were observed more in poorly differentiated invasive cSCCs. Central keratin plugs (87.5%) and branched vascular arrangements (75%) were observed in patients with nodular KA, with both statistically more frequent than in invasive cSCC (p <
0.001, p = 0.040, respectively). White halos surrounding vessels (p = 0.004) and a clustered vessel arrangement (p = 0.037) were more common in nodular invasive cSCC compared to nodular KA. STUDY LIMITATIONS: The number of examined lesions in the subgroups was relatively small. CONCLUSIONS: Dermoscopy aids in distinguishing well-differentiated invasive cSCC from poorly differentiated invasive cSCC, distinguishing nodular KA from nodular invasive cSCC, and diagnosing BD. Further studies are needed to identify dermoscopic findings that can distinguish moderately differentiated invasive cSCC from other invasive cSCCs.