Compact Core, Extended Reach: A Bipolar kpc-Scale Elongation in a Little Red Dot at $z\approx 5.5$

Little Red Dots (LRDs) appear extremely compact at rest-frame optical wavelengths, yet many show extended rest-frame UV morphology revealing more complex internal structure. We present a combined analysis of VLT/MUSE rest-frame UV integral-field spectroscopy and continuum-subtracted [O III], H$\beta$, and H$\alpha$+[N II] emission-line maps from JWST/NIRCam imaging at sub-kpc resolution for LRD-204851 at $z=5.482$ in GOODS-S. We find that LRD-204851 hosts a remarkably thin, bipolar, elongated structure passing through the optical continuum centroid and extending several kpc on either side, traced by both the UV continuum and the rest-frame optical emission lines, with a bright [O III] clump-like structure $\sim$2 kpc to the south-east of the centroid. The MUSE observations reveal a double-peaked Ly$\alpha$ profile, with a broad and bright near-systemic red peak and a relatively faint peak blueshifted by $\sim$430 km s${}^{-1}$, accompanied by a tentative N V $\lambda 1238$ detection at similar velocity. In narrow-band imaging extracted from the MUSE IFU cube, both the blue Ly$\alpha$ peak and the tentative N V emission lean toward this same south-eastern direction. Independently, radiative-transfer modeling of the integrated Ly$\alpha$ profile favors a biconical low-column-density cavity in a dense, slowly expanding neutral envelope, in support of the bipolar geometry traced by the line maps. Together, these results suggest that the elongated emission of LRD-204851 is connected to radiation and/or gas flow from its central engine through a low-column-density channel with a small opening angle that may trace either a slow outflow or a quasi-static ionization cone. LRD-204851 is one of the first LRDs where the central engine’s impact on its host galaxy is potentially directly observable on kpc scales.