Treatment of disorder
olfactory neuroblastoma is a scarce brain tumor developed from olfactory epithelia above nasal cavity. It takes 2-3% of nasal sinus tumor, and onset in 0.4 person per one million. It spreads out widely from younger age to aged person, and its onset peak age is regarded as 20’s and 60’s. Tumor infiltrate from subdural to inside of brain, so that even for the case where complete resection seems successful, tumor may gradually turn into distal metastasis over the years, and develops lesion here and there along the subdural inside of the skull, or multiple lesion may be developed by cerebrospinal fluid dissemination.
Symptoms are blocked nose or bleed nose. As tumor increased, patients turned to self-recognize the disorder of smell.
Tumor area is identified by CT and MRI, then with performing pathological check and diagnose the disease.
Complete resection by surgery is very important, and post-surgical irradiation therapy is the basic treatment. As for surgery, craniofacial resection, which requires neurosurgical craniotomy procedure is selected. Complete resection of tumor and anterior skull base reconstructive surgery are necessary under the in-depth surgical plan. In case epidural infiltration exists, resection should be made for broader area than tumor itself. In this case, rich blood flow galea is used for subdural formation as double pendulous flap in order for not to leak spinal fluid. Regarding the skin cut of scalp, both side coronary incision is performed 2 cm back of coronal suture to keep enough galea, also, both side temporal craniotomy shall be made with broader area is necessary. Frontal skull base formation is conducted with keeping big enough area at the splitting of free bone fragments by open head. In the past, collecting the costal bone, then broke into half then used for the surgery, but patients burden becomes much lighter with this method. Normally, in case of olfactory neuroblastoma, rectus abdominis musculocutaneous flap will not be used for resection cavity so that it is not necessary to prepare these.
We have to rely on chemotherapy for the treatment of unresectable or remote metastasis case. There is no setup treatment at this moment, but chemotherapy with primarily cisplatin (cisplatin + etoposide treatment, cisplatin + irinotecan treatment) is used. However, enough effect cannot be achieved at this moment. Dural infiltration is slowly developed then multiple metastatic lesion is produced.