Basal cell carcinoma (BCC) is the most frequent skin malignant tumor in the human being. Biological aggressiveness is usually low having a local invasive property with anecdotical metastases.
Therefore local assessment of BCC invasiveness is crucial in preoperative planning.
Skin ultrasound is a first line diagnostic procedure in facial BCC as Dr. Wortsman indicates in her latest paper, as it can clearly outline margins and extension of BCC
Sonographical aspects of BCC
BCC is usually a hypoechoic, well circumscribed dermal epidermal lesion. Intratumoral echogenicity is heterogeneous and in some ocasions, hyperechoic dots can be noted.
Respect to vascularization, in most cases increased neovascularization both intratumoral and extratumoral is present. Typical branched neovascularization observed in dermoscopy is sometimes observed.
Typical BCC ultrasound lobulated hypoechoic stroma
with hyperechoic dots inside.
Three main pitfalls have to be taken into account when interpreting BCC ultrasound scans:
- Peritumoral inflammation oversizes ultrasonographic limits of BCC.
- Sebaceous hyperplastic glands may oversize BCC ultrasonographic profile.
- Skin elastosis in aged skin patients may hinder clear margins.
Histological correlation of ultrasound in BCC
Studies about histological correlations of BCC depth with histological measurement (BCC «Breslow») are gaining strength in indicating high correlation indexes nearly 90% (1) .
Factors as histopathological subtype and other skin locations are still lacking but under research by Dr. Maite Lopez Villaescusa (Albacete, Spain) . She will present a poster on superficial BCC recurrences evaluated by US in next AEDV Congress (Valencia June 5-8th).
Dr. Maite López will expose preliminary findings in this blog in a forthcoming post.
Role of ultrasound in assessing posible casuses of recurrence of non invasive therapies are also being evaluated by the group of Dr. Carlos H Ibáñez and and Dr. Magdalena de Troya and in Hospital Costa del Sol (Malaga Spain).
Analysis of image with conventional image analysis software to improve this measurement accuracy is also an area of interest and research as exposed by Dr. Paco de Cabo in our last SEECO course.
BCC. Ultrasonographicall Heterogeneity makes differential diagnosis with melanoma
BCC ultrasound and Mohs surgery
We could think that as a margin establishing as initial Mohs step could be of help. Studies on this area lack scientific strength to assert the lack efficacy or usefulness of this technique as step saving adjuvant technique.
In a research by Marmur et al (2) US scans were performed by technicians and not by surgeon. Clinical relevant factors as location or histological subtype or measurement are not taken into account.
TAKE HOME MESSAGES
- Ultrasound is useful when assessing structural invasivenes of BCC.
- When interpreting theses scans be careful with aging, inflammation and sebaceous hyperplasia.
- Margin assessment with US is a promising field that deserves further interest.
(1) Nassiri-Kashani M, Sadr B, Fanian F, Kamyab K, et al .Pre-operative assessment of basal cell carcinoma dimensions using high frequency ultrasonography and its correlation with histopathology.Skin Res Technol. 2013 Feb;19(1):e132-8.
(2) Marmur ES, Berkowitz EZ, Fuchs BS, Singer GK, Yoo JY.Use of high-frequency, high-resolution ultrasound before Mohs surgery. Dermatol Surg. 2010 Jun;36(6):841-7. .
Last paper of Dr. Wortsmann is worth reading to deepen into this topic
If you want to listen about ultrasonographic aspects of skin tumors, the talk by Dr. Alfageme in the last SEECO course is also availabe in you tube and ppt in slideshare