33 YEAR‐OLD WOMAN WITH A LARGE SELLAR TUMOR

Clinical History

A 33 year old female patient presented in June 2009 with progressive loss of vision for the last 12 months plus occasional episodes of headache. In the last 3 months her vision deteriorated even further with progressive temporal amaurosis, and she started having depression with episodes of extreme anxiety. She developed amenorrhea since her last pregnancy 8 years ago with episodes of galactorrhea. CT scan (Figure 1) showed a mass lesion in the sellar region suggestive of meningeoma or pituitary adenoma. She received bromocriptine 2.5mg/day with no reduction of the lesion. She developed panhypopituitarism with normal levels of prolactin. Further MRI showed a large lesion infiltrating cavernous sinuses and compressing the optic nerve. Transsphenoidal surgical treatment was performed. Two months after the first operation she returned to hospital with complete bilateral amaurosis and a new MRI showed residual lesion. A new sub‐frontal neurosurgery was performed and most of the lesion was resected. The patient developed diabetes insipidus but remains under control.

Figure 1.

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Histological Findings

Several fragments of gray elastic tissue were received for histological examination. Sections showed, apart from small fragments of normal pituitary, the presence of tumor cells arranged in nests and lobules separated by a delicate vascular network (Figure 2). Tumor cells were large with clear or slightly eosinophilic cytoplasm (Figure 3) with moderate nuclear pleomorphism with vesicular nuclei and occasional nucleoli. Mitotic figures were rare and there was no necrosis. Reticulin stains (Figure 4) demonstrated a characteristic pattern. Immunohistochemistry showed positivity for chromogranin A, neuron‐specific enolase and synap tophysin (Figure 4) with a few cells positive for S100. Ki67 was 1‐2%. Vimentin was positive in the vascular network. All pituitary hormonal antibodies were negative as well as GFAP, AE1/AE3, p53 and EMA. What is the diagnosis?

Figure 2.

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Figure 3.

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Figure 4.

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Diagnosis

Paraganglioma of the sellar region.

Discussion

Paragangliomas are rare neuroendocrine tumors that might affect several different regions including head and neck, adrenal, filum terminale and even central nervous system. Paragangliomas affecting the sellar region are extremely rare with a few documented cases so far 1, 2, 3, 4, 5, 6.

The development of paragangliomas in unusual regions such as the sella turcica might be due to the presence of remnants of paraganglionic tissue or due to abnormal migration; it is important to notice that no paraganglionic cells are detected in pituitary or adjacent tissue in adults. However in fetal and neonatal period, neural crest tissue might be seen in avian embryo and these cells could be the origin of abnormal paraganglionic tissue. Furthermore, aggregates of paraganglionic cells were seen in glossopharyngeal nerve within petrous bone in previous reports.

The differential diagnosis of paraganglioma of the sellar region must include pituitary adenomas and meningiomas, both more frequently seen than this unusual lesion. Other clear cell tumors must be also considered in the differential diagnosis, including metastatic renal carcinoma and melanoma. There is no specific clinical or radiological presentation for this rare lesion and histological examination is required for diagnosis. In this case, the characteristic finding of clusters of neuroendocrine tumor cells (zellballen) and the presence of scattered S‐100 sustentacular cells are classic for paraganglioma. The negativity for epithelial markers is important to rule out metastatic carcinoma while the negativity for vimentin, HMB45, melan‐A and S100 helps to rule out melanoma.

In the present case the clinical and radiological findings suggested a pituitary adenoma, probably with prolactin production inducing amenorrhea and galactorrhea in the clinical evaluation. After surgical treatment the final diagnosis of paraganglioma was confirmed.

Abstract

The authors describe a case of paraganglioma of the sellar region in a young female patient with loss of vision and headache. She presented with amaurosis, depression, anxiety and amenorrhea. Clinical and radiological impression was that it was a meningioma or pituitary adenoma. She received bromocriptine with no reduction of the lesion. She developed panhypopituitarism, but with normal levels of prolactin. It was resected and histological examination revealed nests of large cells with moderate nuclear pleomorphism, vesicular nuclei with occasional nucleoli. There were rare mitotic figures, but no necrosis. Immunohistochemistry was positive for synaptophysin, chromogranin A, and neuron‐specific enolase with a few sustentacular cells positive for S100. The Ki67 proliferation was 1‐2%. All pituitary hormonal antibodies were negative as well as GFAP, AE1/AE3, p53 and EMA. Paragangliomas affecting the sellar region are extremely rare and might be due to the presence of remnants of paraganglionic tissue or abnormal migration. The patient's post‐operative diabetes insipidus remains under medical control.