Table 3.
Key articles comparing ultrasound imaging and histopathology.
| Tumor type | Year | Main findings | Correlation with histopathological findings | Probe frequency | Sample size |
|---|---|---|---|---|---|
| Basal cell carcinoma (3) | 2008 | 1. BCC tumor ultrasound shows an oval and hypoechoic lesion 2. Compare tumor thickness measurements between ultrasound and histology |
Good thickness correlation with histology (intraclass correlation coefficient, 0.9) | 7–15 MHz probe | 25 patients |
| Basal cell carcinoma (4) | 2007 | Lesions that may have a higher aggressive potential may also appear as hyperechoic spots | Hypersonographic spots in BCCs seemed to correspond to calcification, horn cysts, or clusters of apoptotic cells in the centers of nests of basal cell carcinoma | 15 or 30 MHz | 29 basal cell carcinomas |
| Invasive squamous cell carcinoma (5) | 2009 | SCC metastasized to lymph node showed asymmetrical cortical area with high elasticity | Presence of metastatic tumor cells located asymmetrically in a small section of the cortical area | Not mentioned | 1 patient |
| Merkel cell carcinoma (6) | 2017 | 1. Hypoechoic pattern with variable vascularization 2. Useful in the diagnostic work-up of MCC and can help more precisely delimit the tumor prior to complete surgical resection |
Not mentioned | 18 MHz | 7 patients |
| Pilomatricoma (7) | 2005 | Well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior acoustic shadowing | Inner echogenic foci may relate with calcification or ossification | 7–12 MHz | 20 pilomatricomas from 19 patients |
| Trichilemmal cyst (TC) (8) | 2019 | Well-defined hypoechoic lesions with internal calcification and posterior sound enhancement | TC contains homogeneous eosinophilic keratinous materials Calcified foci within this keratin can be found | 3–12 MHz 6–18 MHz | 54 TCs from 50 patients |
| Ruptured epidermal cyst (REC) (9) | 2008 | RECs were classified into three types: with lobulations showing echogenic inner contents (type I), with protrusions (type II), and with abscess pocket formations showing poorly defined pericystic changes and increased vascularity around the abscess formation (type III) | Histopathology of the excised RECs also showed similar morphology | 5–10 MHz 5–12 MHz | 13 patients |
| Lipoma in the forehead (10) | 2016 | 1. Hyperechoic striated septae parallel to the skin suggestive of lipoma 2. Ultrasonographic findings were accurate in 9 of 14 cases (64.3%). |
Unlike the preoperative ultrasonographic findings, 13 of 14 cases were confirmed as frontalis-associated lipomas intraoperatively | 12 or 15 MHz | 14 patients with lipomas in the forehead |