Artikel
Pituitary autoimmunity in a case of intra-and suprasellar germinoma
Nachweis von Hypophysenautoantikörpern in einer Patientin mit einem intra- und suprasellären Germinom
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Autoren
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A. Gutenberg
- Department for Neurosurgery, Georg August University Göttingen, Germany
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J. Bell
- Department for Pediatrics, Texas Children's Hospital, Houston, Texas, USA
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I. Lupi
- Department for Pathology, Johns Hopkins University, Baltimore, USA
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R. Salvatori
- Department for Endocrinology, Johns Hopkins University, Baltimore, USA
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P. Caturegli
- Department for Pathology, Johns Hopkins University, Baltimore, USA
| Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: Germinomas of the brain are rare (0.4 to 3.4% of all primary intracranial tumors), occur mainly in pre-pubertal children, and are most often located the pineal or suprasellar regions. Sellar germinomas are even more rare, and can be clinically and pathologically misdiagnosed as autoimmune hypophysitis, because they feature an abundant lymphocytic infiltrate. Distinction between the two entities is crucial because of their different treatment. Considering the lack of specific serum biomarkers in most intracranial germinomas (80% are beta human chorionic gonadotropin negative), and the possible utility of pituitary autoantibodies in hypophysitis, we evaluated the presence of such antibodies in a case of intra- and suprasellar germinoma initially misdiagnosed as hypophysitis.
Results: An 11-year-old girl was referred because of diabetes insipidus and growth retardation, and found to have an intra- and suprasellar mass. Initial exam of the biopsy showed a diffuse lymphocytic infiltration of the anterior pituitary, negative for placental alkaline phosphatase, leading to a diagnosis of hypophysitis and corticosteroid treatment. Because of the lack of response, the pituitary specimen was re-examined and revealed the presence of scattered c-kit and Oct4 positive germinoma cells, which prompted the initiation of radiotherapy with disappearance of the pituitary mass. We assessed the presence of autoimmunity in this patient using immunohistochemistry, 1D immunoblotting, and 2D electrophoresis followed by mass spectrometry sequencing. The patient serum recognized on immunohistochemistry antigens expressed by the germinoma cells; in addition, it identified by immunoblotting several pituitary cytosolic proteins among which were alpha-subunit of human choriogonadotropin and alpha-enolase. The antibody profile was not restricted to the pituitary but included reactivity to the Sjögren syndrome antigen B (anti-La), although the patient had no signs or family history of systemic autoimmunity.
Conclusions: The study first reports the presence of pituitary antibodies in a case of intrasellar germinoma, and shows that such antibodies, as assessed by current methods, are not helpful in distinguishing it from hypophysitis. The co-existence germinoma antibodies, furthermore, raises questions about shared antigens between pituitary and germinoma cells as well as the role of lymphocytes.
