Ultrasonographic characteristics of Bowen's disease

Background: Bowen's disease (BD), or squamous cell carcinoma in situ, is an epithelium-derived tumor with high oncogenicity. Nowadays, high frequency ultrasonography is widely used for non-invasive diagnosis of skin tumors. The results of investigations into the echo signs of BD are contradictory, while they based on the use of 20 and 45 MHz converters. To make intra-epidermal lesions visible, it is necessary to use sonographic converters with at least 50 MHz resolution. 
Aim: To determine ultrasonographic signs of BD with the use of a high frequency 75 MHz sensor. 
Materials and methods: We examined 8 patients (2 women and 6 men) aged 38 to 86 years with histologically confirmed BD diagnosis. With a high resolution ultrasonographic system (75 MHz sensor) we scanned 8 solid BD lesions and 8 visually unchanged contralateral skin areas as controls, measuring the epidermal and dermal thickness, depth of hypodense areas in derma in the chosen regions of interest. 
Results: The ultrasonographic picture of the BD lesions was characterized by hyperdense epidermis of two types: the first one (n = 6) was of uneven thickness and wave form, with budlike sprouts into the dermal depth, while the second one (n = 2) was of similar width all through, with even external and internal contours. Mean epidermal thickness in the BD lesions was significantly different from that of the contralateral visually unchanged skin areas (192.37 75.48 vs 69.88 12.48 mcm, p = 0.011719). In BD lesion, there were intradermal hypodense areas located just under the epidermis; they included diffuse and heterogeneous band-like structures in the type 1 lesions and round structures in the type 2 lesions. The mean thickness of the hypodense BD zones in the tumor located in the open skin areas was bigger than that in those located in the closed skin areas (1288.25 450.25 vs 585.75 150.62 mcm, p = 0.025348). 
Conclusion: With ultrasonographic scanning with a 75 MHz sensor, we have identified the following BD characteristics: thickened epidermis with an even internal contour and hypodense intradermal areas of diffuse heterogeneous structures, which had the biggest depth in the lesions located in the open skin areas. The ultrasonographic picture of BD can be of two types depending on the combination of the main signs with different shape.