Fig. 1

a and b Enhanced CT findings before operation. The tumor (arrow) was mainly located in the left lobe and invaded into half the tracheal circumference (40 × 36 mm) (Fig.2(A)). c and d Recurrent tumor was found just below the left piriform fossa (15 × 11 mm) (c), and lung metastasis (max, 6 mm) (d) was found at the same time 3 months after the operation by CT scan (Fig.2(B)). e, f, and g Nine months after the operation, CT scan showed prominent tumor progression in the neck (48 × 38 mm) (e) and the lung (18 × 16 mm) (f). Additionally, bone scintigraphy demonstrated a solitary bone metastasis in the right scapula (g) (Fig.2(C)). h and i Three years after the operation, local recurrence in the neck was controlled (15 × 11 mm) (h), although multiple metastasis in the lung worsened (PD). Maximum size was 30 × 26 mm (i) (Fig.2(D)). j and k Within 8 months after starting sorafenib, local recurrence (j) and lung metastasis worsened (PD) (k) (Fig.2(E)). l and m Within 1 month after starting lenvatinib, the tumor in the neck remained controlled (l) and multiple metastases in the lung decreased and diminished in size (18 × 15 mm) (m) (PR) (Fig.2(F)). n Within 3 months after starting lenvatinib, pin-hole perforation (5 mm) of the trachea suddenly appeared at the end of tracheal invasion (Fig.2(G)). o Within 1 month after terminating lenvatinib, the perforation was naturally cured and pin-hole closed (Fig.2(H)). p and q Within 2 months after restarting lenvatinib, tumors in the neck (p) and the lung (q) were controlled (PR) (Fig.2(I)). r and sAlthough local recurrence (r) was kept controlled, lung metastasis (s) was exacerbated (21 × 18 mm) for 2 months after terminating lenvatinib because of adverse events (PD) (Fig.2(J)). tand uWithin 3 months after restarting lenvatinib, local recurrence in the neck (t) and lung metastasis (u) remained under control (PR) (Fig.2(K)). v and w One year and 9 months after starting lenvatinib, CT scan still showed PR (Fig.2(L))