Rare forms of hyperthyroidism
David S. Cooper, Jennifer A. Sipos in Medical Management of Thyroid Disease, 2018
Thyrotropin (TSH)-secreting pituitary adenomas are rare tumors that indicate an uncommon cause of hyperthyroidism. The diagnosis of a TSH-secreting pituitary adenoma can present a challenge, and may be difficult to distinguish from thyroid hormone resistance (RTH). TSH-secreting adenomas usually have a disproportionate hypersecretion of the alpha subunit of glycoprotein hormones, leading to an elevated molar ratio of serum alpha subunit to TSH. Resistance to thyroid hormone is a rare inherited disorder characterized by the reduced responsiveness of target tissues to thyroid hormone and can result in a wide range of clinical features from hypothyroidism to hyperthyroidism. A broad range of clinical symptoms have been reported with RTH but most commonly patients present without severe clinical symptoms despite the abnormal thyroid function tests. Interestingly, clinical symptoms vary widely from patient to patient even within families who harbor the same mutation. Differentiated thyroid cancer metastases can rarely produce excess thyroid hormone and result in hyperthyroidism.
Pituitary Tumors
Dongyou Liu in Tumors and Cancers, 2017
This chapter presents a state of the art summary of pituitary tumors relation to its biology, epidemiology, disease mechanisms, clinical signs, diagnosis, treatment and prognosis. Among tumors of the pituitary gland, pituitary adenomas are most common, while pituitary carcinomas may occasionally affect older people. Pituitary tumors, accounting for 10%–25% of all intracranial tumors, mainly occur in the fourth and seventh decades, with female preponderance. Differential diagnoses for pituitary adenomas and carcinomas include rare tumors/lesions that also occur at the suprasellar and sellar regions. Pituitary adenoma is composed of monomorphic cells with small, round nuclei, salt-and-pepper chromatin, and abundant cytoplasm without reticulin meshwork among tumors cells. Pituicytoma is a rare benign tumor derived from pituitcytes in neurohypophysis or pituitary infundibulum, possesses bland spindle cells in dense fascicles or storiform growth pattern, and stains positive for vimentin, S100 protein, and thyroid transcription factor-1; but, it is negative for neuroendocrine markers and pituitary hormones.
Optic chiasm
Fiona Rowe in Visual Fields via the Visual Pathway, 2016
Crossed and uncrossed retinal nerve fibres begin to separate at the termination of the optic nerve at the anterior angle of the optic chiasm. The blood supply to the optic chiasm is from an anastomosis of arterioles from the Circle of Willis. Lesions that compress the optic chiasm include aneurysms, craniopharyngiomas, distension of the third ventricle in obstructive hydrocephalus, optic nerve and chiasmal gliomas and pituitary tumours. Meningiomas that involve the optic chiasm may arise from the olfactory groove, tuberculum sellae or lesser wing of sphenoid and are slow growing. Pituitary adenoma is the most common intracranial tumour to involve the optic chiasm. A dilatation of an internal carotid aneurysm may cause lateral compression of the optic chiasm. Associated ocular signs and symptoms include hemifield slide, postfixation blindness, extraocular muscle palsies, optic atrophy, pallor, diplopia and oscillopsia. In addition to assessment of visual fields in patients with optic chiasm lesions, fundus examination is an important part of the ophthalmic investigation.
Neurosurgical image: giant pituitary adenoma and multiple aneurysms
Published in British Journal of Neurosurgery, 2019
Himanshu Agarwal, Chandril Chugh, Saraj Singh, Prakash Singh
Pituitary adenomas are associated with intracranial aneurysms. Giant non-functioning pituitary adenomas with aneurysms in their vicinity pose technical surgical challengesas aneurysm rupture can be catastrophic during surgery. We present the case of a middle aged women who presented with progressive visual loss in both eyes caused by a giant pituitary adenoma compressing the optic chiasma. She also had associated mirror image carotid aneurysms embedded in the tumour. They were successfully coiled preoperatively and the tumour was removed safely with improvement of her symptoms.
Spontaneous preoperative pituitary adenoma resolution following apoplexy: a case presentation and literature review
Published in British Journal of Neurosurgery, 2020
Daniel G. Eichberg, Long Di, Ashish H. Shah, William A. Kaye, Ricardo J. Komotar
Purpose: We aim to more fully understand the incidence and natural history of spontaneously resolving non-functioning pituitary adenomas (NFPAs). Methods: We report a case of spontaneous complete resolution of a NFPA revealed by preoperative magnetic resonance imaging. In addition, we searched all major databases and neurosurgery journals to perform a comprehensive literature review of all previously reported cases of spontaneously resolving NFPAs. We discuss how these cases may contribute to our understanding of the natural course for non-functional pituitary adenomas. Results: To date, only twelve cases of spontaneously resolving nonfunctional pituitary adenomas have previously been reported. The presented case is the first reported spontaneously resolved nonfunctioning pituitary adenoma to recur. In all cases, apoplexy resulted in resolution of mass effect, obviating the need for surgical decompression. Conclusions: In all NFPA cases, the preoperative MRI should always be studied closely before surgery is initiated. Additionally, because we have demonstrated that the adenoma may regrow after spontaneous regression following apoplexy, these patients should be followed with regular serial MRIs to monitor for recurrence.
Current imaging techniques for the diagnosis of pituitary adenoma
Published in Expert Review of Endocrinology & Metabolism, 2016
Hasan A. Zaidi, David J. Cote, Edward R. Laws
Stepwise improvements in the imaging of pituitary adenomas in the last 100 years have had a tremendous impact on patient care. Pituitary tumors are now diagnosed earlier in the time course of the disease, improving chances of endocrine and visual recovery. There is improved pre-surgical planning due to a better understanding of the investment of the tumor around important surrounding parasellar structures. Approaches to tumors are now safer due to stereotactic navigation and residual disease can be radiographically followed for a lifetime and treated prior to irreversible neurological damage. Furthermore, adjuvant radiotherapy can be more precisely delivered to the tumor bed with the aid of higher resolution images. Thanks to these incremental improvements previously formidable macroadenomas, which carried a high risk for morbidity and residual disease, can now be treated safely and effectively. Here, we review modern imaging modalities used to diagnose pituitary adenomas, and identify areas for further improvement.
Related Knowledge Centers
- Neurohypophysis
- Pituitary Diseases
- Pituitary Gland
- Acromegaly
- Optic Chiasm
- Optic Nerve Neoplasms
- Endocrine Gland Neoplasms