Aggressive silent corticotroph adenoma progressing to pituitary carcinoma: the role of temozolomide therapy.

Abstract

Temozolomide (TMZ) has recently been recommended as a novel approach in the management of aggressive pituitary tumors. Herein, we present the case of a 43-year-old man with a 20-year history of silent subtype 2 pituitary corticotroph adenoma. Nine surgical resections and radiotherapy had failed to provide a cure. Morphological evaluation of the tumor revealed a mildly pleomorphic adenoma, the cells of which showed low-level cell proliferative activity with Ki67, increased topoisomerase II alpha index and conclusive O-6-methylguanine-DNA methyltransferase (MGMT) as well as vascular endothelial growth factor (VEGF) immunoreactivity. Given its aggressive behavior and failure of conventional therapy, TMZ was administered. The treatment was continued even after MGMT immunopositivity was identified, but failed to decrease MGMT immunoexpression and exerted no morphologic effect. Examination of the lesion after TMZ therapy showed neither morphologic nor immunohistochemical alterations. In our case, TMZ administration, despite changing the TMZ dosing regimen to prompt a drug response, was incapable of depleting MGMT stores.

• Authors: Olga Moshkin, Luis V Syro, Bernd W Scheithauer, Leon D Ortiz, Camilo E Fadul, Humberto Uribe, Ricardo Gonzalez, Michael Cusimano, Eva Horvath, Fabio Rotondo, Kalman Kovacs
• Journal: Hormones (Athens, Greece) (Hormones (Athens)) 2011 Apr-Jun Vol. 10 Issue 2 Pg. 162-7 ISSN: 2520-8721 [Electronic] Switzerland
• PMID: 21724542 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents, Alkylating
• Tumor Suppressor Proteins
• VEGFA protein, human
• Vascular Endothelial Growth Factor A
• Dacarbazine
• DNA Modification Methylases
• MGMT protein, human
• DNA Repair Enzymes
• Temozolomide

Topics

• ACTH-Secreting Pituitary Adenoma (drug therapy, pathology)
• Adenoma (drug therapy, pathology)
• Adult
• Antineoplastic Agents, Alkylating (therapeutic use)
• Carcinoma (drug therapy, pathology)
• DNA Modification Methylases (metabolism)
• DNA Repair Enzymes (metabolism)
• Dacarbazine (analogs & derivatives, therapeutic use)
• Humans
• Male
• Pituitary Neoplasms (drug therapy, pathology)
• Temozolomide
• Tumor Suppressor Proteins (metabolism)
• Vascular Endothelial Growth Factor A (metabolism)