Characteristics of Mixed Type Basal Cell Carcinoma in Comparison to Other BCC Subtypes

Background: There are limited data exploring the characteristics of mixed type basal cell carcinoma (BCC). Objectives: To explore different characteristics of mixed type BCC. Design: Cross sectional study. Materials and Methods: 825 patients with BCC enrolled in this study. Results: Among 825 patients, 512 (62%) were male. Three hundred and fifty five (43%) presented with nodular subtype, 267 (32.4%) with mixed subtype, 25 with superficial and the 178 remaining presented with other subtypes. Four hundred and eighty three (58.6%) of the lesions were on the face, 243 (29.5%) on scalp, 52 (6.3%) on ears, 20 (2.4%) on neck, 15 (1.8%) on trunk and 12 (1.4%) on extremities. Anatomic distribution of mixed type was as follows: 137 on face, (51.4%), 100 (37.3%) on scalp, 19 (7%) on ear, 6 (2.1%) on neck, 4 (1.5%) extremity and 1 (0.7%) on trunk, which the difference from non mixed types was statistically significant (P = 0.002). The mean diameter of the mixed types and non mixed type BCCs were significantly different (2.7 +/- 2.1 cm vs. 2.2 +/- 1.6 cm; P = 0.01. The prevalence of necrosis in mixed type BCC was two times higher than non mixed type BCCs (OR = 2.3, CI 95% 1.3-3.9, P = 0.001). The most frequent combined subtypes were nodular-infiltrative (P < 0.001). Conclusion: Mixed type BCC has differences with other BCC subtypes in anatomical distribution and tumor diameter. Indeed, mixed type BCCs are frequently composed of aggressive subtypes than nonaggressive subtypes.