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Imaging in Head and Neck Endocrine Disease
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
These are rare, WHO grade 1 tumours and are classified as pituicytoma, spindle cell oncocytoma and granular cell tumour.9 They can also present with visual loss and endocrine disturbance.
Pituitary Tumors
Published in Dongyou Liu, Tumors and Cancers, 2017
Pituicytoma is a rare benign tumor derived from pituitcytes (modified glial cells) 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 (TTF-1); but, it is negative for neuroendocrine markers (i.e., synaptophysin) and pituitary hormones.
Endocrine Glands
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Richard A. Peterson, Sundeep Chandra, Mark J. Hoenerhoff
Since the majority of these tumors contain prolactin cells, it has been suggested that decreased hypothalamic content of dopamine observed in older rats may be an important factor as dopamine is the main inhibitory factor for prolactin (Prysor-Jones et al. 1983). The higher incidence of pituitary adenomas in females suggests that estrogen is involved, either by a direct effect on the pituitary cells or through inhibition of dopamine. A small number of spontaneous adenomas also develop from cells of the intermediate lobe in rats and show immunohistochemical staining for ACTH (McComb et al. 1984, 1985). Multiple studies have shown the influence of dietary factors on both the incidence and onset of pituitary tumors in rats (Duffy et al. 2008; Keenan et al. 1995a,b). A lower incidence of pituitary tumors in rats fed with a restricted diet was associated with decreased circulating levels of prolactin, estradiol, LH, and IGF-1; reduced volume of GH and prolactin-containing cells; and a lower proliferation index in the pituitary gland (Molon-Noblot et al. 2003). Pituitary carcinomas cannot be readily distinguished from adenomas based on the nature of the cells and the architectural pattern of the neoplasm (Figures 19.1c and d). Differentiating factors between adenomas and carcinomas include the presence of distant metastasis or aggressive local invasion of the adjacent brain or the sphenoid bone, the latter representing the most common evidence of malignancy. Local invasion must be differentiated from expansive growth commonly seen with adenomas (Majka et al. 1990). Other proliferative lesions, including craniopharyngioma (Heider 1986; Pace et al. 1997) and pituicytoma (Satoh et al. 2000), are rare neoplasms, and isolated cases have been described. Adenomas of the pars intermedia are uncommon in rats. Spontaneous pituitary neoplasms are less common in mice. The FVB/N mouse strain has a high prevalence of prolactin-secreting pituitary proliferative lesions (hyperplasia and adenoma), with secondary effects on the mammary gland (Wakefield et al. 2003). Similar to rats, dietary restriction reduced the incidence of pituitary and other tumors in diet-restricted B6C3F1 mice compared with ad libitum-fed controls. Pituitary adenomas have been reported in beagle dogs. The neoplasms in dogs appeared as small nodules (2–3.5 mm in diameter), and histologically the tumors were composed of immature or intermediate zone ACTH, cells (Attia 1980). In a retrospective study, spontaneous pituitary adenomas that caused either gross enlargement of the gland or microadenomas that were identified on histologic examination were observed in 14 of 491 cynomolgus macaques (Macaca fascicularis). Pituitary weight was increased due to these tumors. A total of 35 adenomas were identified, with mixed histologic appearance and hormone expression, although a majority of the tumors stained immunohistochemically for prolactin (Remick et al. 2006).
Non-adenomatous pituitary tumours mimicking functioning pituitary adenomas
Published in British Journal of Neurosurgery, 2020
Zize Feng, Zhigang Mao, Zongming Wang, Bing Liao, Yonghong Zhu, Haijun Wang
In contrast to these cases, several cases of pituicytomas or GCTs without accompanying hyperplasia or adenoma have been reported. In 2013, Chakraborti et al.18 reported a case involving symptomatic corticotropin hypersecretion. The patient underwent an endoscopic transsphenoidal procedure and excision of the tumour. The pathological analysis results revealed a pituicytoma. Postoperative serum ACTH hormone and cortisol levels decreased to normal, and the symptoms resolved. Losa et al.14 reported a case that presented with acromegaly linked to a neurohypophyseal GCT in 2000. Clinical and biochemical remission was achieved after the lesion was removed. The anterior pituitary hormones and GH-releasing hormone (GHRH) of the specimen were proved negative by histological analysis. In our study, one and two cases presented with Cushing’s syndrome and acromegaly, respectively. Two of them achieved remission following total tumour resection, while in one case the tumour was only partially resected. Postoperative histological examination confirmed the diagnosis of pituicytoma or GCT. In all specimens from the three cases, anterior pituitary hormones were undetectable in the immunohistological staining analysis, and no adenomatous evidence was found.
Correlations between clinical hormone change and pathological features of pituicytoma
Published in British Journal of Neurosurgery, 2018
Ting-Wei Chang, Ching-Yi Lee, Shih-Ming Jung, Hung-Yi Lai, Chun-Ting Chen, Mun-Chun Yeap, Chi-Cheng Chuang, Peng-Wei Hsu, Chen-Nen Chang, Po-Hsun Tu, Shih-Tseng Lee
Pituicytoma is a low-grade glioma that arises from the pituicytes in the neurohypophysis, which are mostly located in the posterior lobe of the pituitary or the pituitary stalk.1 Pituicytoma is rare and usually occurs during adulthood, with a slightly higher incidence among males.2 Clinically, pituicytoma can be easily misdiagnosed as nonfunctioning pituitary adenoma due to mass effect,3 and its symptoms include headaches, visual field defects, and hypopituitarism. Occasionally, a pituicytoma is found accidentally during autopsy;4 pituicytoma-induced spontaneous suprasellar haemorrhage has also been reported.5 Notably, patients with pituicytoma who also present with hormone changes are unusual, and their hormone change is mostly triggered by tumour-related mass effect (e.g. hypopituitarism and hormone suppression).6 However, at our institute, we determined that most patients with pituicytomas also presented with hormone elevation. These patients were considered to have a functioning pituitary adenoma before pathological diagnosis. After a review of the English literature, only two case reports of pituicytoma with hormone elevation were found; in both, the patients presented with Cushing disease.7,8 These reports also provided some indications of hormone elevation, but lacked sufficient pathological and immunohistochemical (IHC) examination to confirm this phenomenon. It is unclear whether pituicytoma influences endocrine secretory functions or whether it can raise a normal pituitary gland to hypersecretory status; there has also been no analysis of coexisting pituicytoma and functioning pituitary adenoma tumours. Therefore, this study was designed to elucidate the relationship between pituicytoma and the pituitary gland.