Biomedical subjects
Ken-ichi Oyama
Publications and source records attributed to Ken-ichi Oyama.
Sellar neuroblastoma mimicking pituitary adenoma.
OBJECTIVE AND IMPORTANCE: Primary intracranial neuroblastomas are rare. They generally arise in the supratentorial parenchyma or paraventricular region. Even more rare are primary sellar neuroblastomas. We present a neuroblastoma that arose in the sellar region and mimicked a non-functioning pituitary adenoma. CLINICAL PRESENTATION: This 33-year-old man presented with bitemporal hemianopsia. MRI showed a sellar mass with suprasellar extension mimicking a pituitary adenoma. INTERVENTION: Because of tumor recurrence and dissemination to the cervical region, he underwent 6 operations and radiosurgery. Detailed histologic examination confirmed the diagnosis of neuroblastoma. Postoperative conventional radiotherapy was effective in reducing the size of the tumor. CONCLUSION: Neuroblastoma should be considered in the differential diagnosis of patients with sellar lesions.
Management of pituitary incidentalomas: according to a survey of pituitary incidentalomas in Japan.
The development of computed tomography (CT) and magnetic resonance imaging (MRI) has resulted in the discovery of unsuspected endocrinologically silent pituitary masses (pituitary incidentalomas). The aim of this study was to clarify the natural history of pituitary incidentalomas in order to establish an appropriate approach to them. Five hundred fifty patients with pituitary incidentalomas were analyzed in this study; 261 patients (47.4%) underwent surgery (surgical group; SG), whereas 289 patients (52.6%) were followed up conservatively (nonsurgical group; NSG) for a mean period of 27.3 months (range, 6-173 months). Clinical and biochemical assessment, CT or MRI of the pituitary, and visual field testing were assessed at baseline and at 6 months and yearly thereafter. A total of 261 tumors in the SG group consisted of 211 (80.8%) nonfunctioning pituitary adenomas and 42 (16.1%) Rathke's cysts. During a follow-up period, of 289 tumors in the NSG group, 209 (72.3%) tumors stayed the same size as before, 35 tumors (12.1 %) increased in size, and 41 tumors (14.2%) decreased in size. The estimated diagnoses of the tumors that increased consist of 28 nonfunctioning pituitary adenomas, 5 Rathke's cyst, and 2 others. The decreased tumors consist of 11 nonfunctioning adenomas, 21 Rathke's cysts, and 3 others. Pituitary incidentalomas usually follow a benign course. We recommend transsphenoidal adenomectomy for a solid mass attached to the optic chiasma estimated to be a pituitary adenoma by MRI. Other patients should be followed up by MRI and biochemical assessment. Especially asymptomatic cystic masses (including Rathke's cleft cysts) could be followed up without surgical intervention because they tend to stay the same size or sometimes be cured spontaneously.