Rediscovering the Ciucci pathway: in-vivo evidence of a palmar lymphatic channel

In 1996, Ciucci et al. described the presence of a lymphatic channel in the palmar skin that spanned the first interdigital space and anastomosed with lymphatic collaterals on the dorsal surface of the hand. This palmar lymphatic channel (a pathway we have named the Ciucci pathway) has yet to be described with in-vivo imaging. As the Ciucci pathway is a superficial-to-deep lymphatic communication, its visualization may provide insight into altered lymphatic routing following axillary lymph node dissection (ALND). Therefore, we investigated our ability to image this pathway with indocyanine green (ICG) lymphography.

Healthy female volunteer and female breast cancer survivors without a history of BCRL at least two years after ALND underwent lymphatic mapping of the upper extremities with ICG lymphography. ICG was injected in six standard sites in the hand/wrist and upper arm. The presence of the Ciucci pathway was recorded and compared between cohorts with Fisher's exact test.

110 arms of 55 healthy volunteers and 31 at-risk arms of 31 breast cancer survivors without BCRL were included. The Ciucci pathway was present in one of 110 (0.9%) healthy female volunteer arms and present in five of 31 (16.1%) at-risk arms of breast cancer survivors (p = 0.002).

The Ciucci pathway was more frequently observed in the at-risk arms of volunteers with a history of ALND without BCRL than in the arms of healthy female volunteers. While the functional significance of this pathway remains unclear, its presence may represent superficial-to-deep lymphatic collateralization following ALND.