Fig 6. “The injection [performed on another day] shows crossed drainage from one inguinal side to the opposite side!”.

Phase 3 lymphoscintigraphy [left: Anterior WBS obtained after 1 hour of walking [phase 3] at the end of our exam] revealed in a 13-year-old woman with left-sided primary LLLE at the level of the ankle and calf the following:

• On the right side, normal lymphatic drainage from the foot to the root of the limb was observed, but with one inguinal nodal gap [horizontal arrow] and decreased activity in the common iliac and lumbo-aortic LNs.
• On the left side, normal lymphatic drainage from the foot to the root of the limb was observed, but with limited lymphatic reflux from the inguinal LNs toward the superficial dermal lymphatic network in the upper and inner third of the thigh [oblique arrow]; normal infra-diaphragmatic LN findings were also observed [“gap” in the iliac common area, irregular distribution of the inguinal LNs], but with one LN at the level of the flank [vertical arrow].

The consecutive anterior views centered on the pelvis and abdomen obtained after the intradermal injection performed several days later in the external part of the left buttock revealed [right: From top to bottom and right to left] lymphatic drainage toward the inguinocrural LNs and thereafter in the whole intraabdominal nodal axis but also one LV from the left inguinocrural LNs in the direction of the right inguinal area, crossing the midline before the pubic area and reaching one contralateral inguinal node [vertical arrows].