I would only use 61510.
61510 Description from Coder's Desk Reference: The physician removes a supratentorial abscess or cyst. Supratentorial structures are those located above the tentorium cerebelli, the membrane that separates the cerebellum from the basal surface of the occipital and temporal lobes of the cerebrum. The physician incises and retracts the scalp and removes bone over the area of the tumor, meningioma, abscess, or cyst. The tumor, meningioma, abscess or cyst is identified and excised. The bone is replaced and stabilized. The scalp is anastomosed and sutured in layers. In 61510, the physician removes a brain tumor. In 61512, a meningioma is removed. A meningioma is a tumor of the lining of the brain. In 61514, an abscess is excised. In 61516, a cyst is excised or fenestrated. Fenestration is the surgical creation of an opening or window in the cyst to allow it to drain.
61781 is for stereotactic guidance. I only use 61781 when my surgeons use a neuro navigation system during the procedure. Lay Description: The physician performs cranial or spinal procedures utilizing stereotactic computer-assisted navigation. These codes may only be assigned in conjunction with the primary procedure when the physician uses a computer to assist with coordinate determination established with a CT or MRI scan. Report 61781 for intradural cranial procedures
61321 wouldn't be needed as this is firstly the wrong location(infratentorial) and the excision of the lesion is fully covered by 61510.