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Pituitary Tumors Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Cellular Classification of Pituitary Tumors

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Oncocytic Tumors

Oncocytic tumors of the pituitary, also known as pituitary oncocytomas, are characterized by an abundance of mitochondria, which may fill up to 50% of the cytoplasmic area, which is normally around 8%, and obscure other organelles. These tumors are usually unassociated with clinical and biochemical evidence of hormone excess; in some cases, they may be accompanied by various degrees of hypopituitarism and/or mild hyperprolactinemia. Oncocytic change may occur in several other pituitary tumor types.[1]

Carcinomas

Pituitary carcinomas are usually endocrinologically functional, and ACTH-producing and PRL-producing tumors are the most frequent.[2,8] The histological and cytological characteristics of pituitary carcinomas vary from bland and monotonous to frankly malignant.[22] Carcinomas show a variable degree of nuclear atypia and cellular pleomorphism, but they also show significantly higher mitotic rates and cell proliferation indices than adenomas.[2] Carcinomas account for 0.1% to 0.2% of all pituitary tumors.[8,16]

Metastatic Tumors

Breast and lung cancer are the most common primary neoplasms metastasizing to the pituitary. Although tumors that are metastatic to the pituitary have been reported to be as high as 28% in autopsy series, the majority of metastatic tumors are clinically silent.[23]

Other Tumors

Other tumors that arise in the pituitary include craniopharyngiomas, meningiomas, and germ cell tumors; the rare granular cell tumors, pituicytomas, and gangliogliomas; and the even rarer gangliocytomas, lymphomas, astrocytomas, and ependymomas.[2]

References:

  1. Kovacs K, Horvath E, Vidal S: Classification of pituitary adenomas. J Neurooncol 54 (2): 121-7, 2001.
  2. Ironside JW: Best Practice No 172: pituitary gland pathology. J Clin Pathol 56 (8): 561-8, 2003.
  3. Ezzat S, Asa SL, Couldwell WT, et al.: The prevalence of pituitary adenomas: a systematic review. Cancer 101 (3): 613-9, 2004.
  4. Hardy J: Transsphenoidal surgery of hypersecreting pituitary tumors. In: Kohler PO, Ross GT, eds.: Diagnosis and treatment of pituitary tumors: proceedings of a conference sponsored jointly by the National Institute of Child Health and Human Development and the National Cancer Institute, January 15-17, 1973, Bethesda, Md. Amsterdam, The Netherlands: Excerpta medica, 1973, pp 179-98.
  5. Elster AD: Modern imaging of the pituitary. Radiology 187 (1): 1-14, 1993.
  6. Chambers EF, Turski PA, LaMasters D, et al.: Regions of low density in the contrast-enhanced pituitary gland: normal and pathologic processes. Radiology 144 (1): 109-13, 1982.
  7. Hall WA, Luciano MG, Doppman JL, et al.: Pituitary magnetic resonance imaging in normal human volunteers: occult adenomas in the general population. Ann Intern Med 120 (10): 817-20, 1994.
  8. Ragel BT, Couldwell WT: Pituitary carcinoma: a review of the literature. Neurosurg Focus 16 (4): E7, 2004.
  9. Asa SL, Ezzat S: The cytogenesis and pathogenesis of pituitary adenomas. Endocr Rev 19 (6): 798-827, 1998.
  10. McComb DJ, Ryan N, Horvath E, et al.: Subclinical adenomas of the human pituitary. New light on old problems. Arch Pathol Lab Med 107 (9): 488-91, 1983.
  11. Yeh PJ, Chen JW: Pituitary tumors: surgical and medical management. Surg Oncol 6 (2): 67-92, 1997.
  12. Scheithauer BW, Kovacs KT, Laws ER Jr, et al.: Pathology of invasive pituitary tumors with special reference to functional classification. J Neurosurg 65 (6): 733-44, 1986.
  13. Della Casa S, Corsello SM, Satta MA, et al.: Intracranial and spinal dissemination of an ACTH secreting pituitary neoplasia. Case report and review of the literature. Ann Endocrinol (Paris) 58 (6): 503-9, 1997.
  14. Kemink SA, Wesseling P, Pieters GF, et al.: Progression of a Nelson's adenoma to pituitary carcinoma; a case report and review of the literature. J Endocrinol Invest 22 (1): 70-5, 1999.
  15. Kaltsas GA, Grossman AB: Malignant pituitary tumours. Pituitary 1 (1): 69-81, 1998.
  16. Pernicone PJ, Scheithauer BW, Sebo TJ, et al.: Pituitary carcinoma: a clinicopathologic study of 15 cases. Cancer 79 (4): 804-12, 1997.
  17. Kovacs K, Horvath E: Pathology of pituitary tumors. Endocrinol Metab Clin North Am 16 (3): 529-51, 1987.
  18. Thapar K, Scheithauer BW, Kovacs K, et al.: p53 expression in pituitary adenomas and carcinomas: correlation with invasiveness and tumor growth fractions. Neurosurgery 38 (4): 765-70; discussion 770-1, 1996.
  19. Garrão AF, Sobrinho LG, Pedro-Oliveira, et al.: ACTH-producing carcinoma of the pituitary with haematogenic metastases. Eur J Endocrinol 137 (2): 176-80, 1997.
  20. Teramoto A, Sanno N, Tahara S, et al.: Pathological study of thyrotropin-secreting pituitary adenoma: plurihormonality and medical treatment. Acta Neuropathol (Berl) 108 (2): 147-53, 2004.
  21. Snyder PJ: Extensive personal experience: gonadotroph adenomas. J Clin Endocrinol Metab 80 (4): 1059-61, 1995.
  22. Pernicone PJ, Scheithauer BW: Invasive pituitary adenoma and pituitary carcinoma. In: Thapar K, Kovacs K, Scheithauer BW, et al., eds.: Diagnosis and Management of Pituitary Tumors. Totowa, NJ: Humana Press, 2001, pp 369-86.
  23. Komninos J, Vlassopoulou V, Protopapa D, et al.: Tumors metastatic to the pituitary gland: case report and literature review. J Clin Endocrinol Metab 89 (2): 574-80, 2004.
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WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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