LAUSR

(Table 1). The ages vary from 18 to 89 years (mean: 46.5 years). The ratio of men to women is 8–4. CC was found to range in diameter from 2 to 30 mm (mean: 11.2 mm). There seems to be no correlation between trauma and the occurrence of CC. CC has been recognized on the face (four cases), sole (three cases), palm (two cases), neck (two cases) and thigh (one case). Humphreys et al. reported familial cases with multiple CCs (No. 2–4) and suggested that the phenomenon is associated with the incomplete expression of the tuberous sclerosis gene. CC can be clinically mistaken for verruca vulgaris, dermatofibroma, glomus tumour, eccrine poroma and pyogenic granuloma. Our review of the literature found that no cases were diagnosed as CC before surgical and histopathological examination. In fact, we clinically misdiagnosed the present case as callus. Regarding the pathogenesis of the callus-like feature, we speculated that chronic endogenic pressure might have thickened the surface and chronic exogenic pressure from the ground might have been what made the surface scaly. As CC can occur at any age and site and can have various clinical features, it is quite difficult to diagnose without histopathological examination. In conclusion, when dealing with callus-like subcutaneous nodules, we should consider CC as a differential diagnosis.