Contributed by Yun-Ho Lee, Young Seok Park, Dong-Seok Kim, Yong-Gou Park and Kyu-Won Shim
Department of Neurosurgery, Severance Hospital, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
CLINICAL HISTORY AND IMAGING STUDIES
A 59-year-old female presented with a severe headache for 3 weeks and was admitted to another hospital for evaluation. Magnetic resonance image (MRI) of the brain revealed a well-delineated homogeneous contrast-enhancing mass lesion within the infundibular recess. Basal pituitary hormones were within normal limits. A combined pituitary hormone test showed only a slightly decreased fT4 (0.7ng/dL). Because she was postmenopausal, LH (1.76mIU/mL) and FSH (1.02mIU/mL) levels were subnormal. Other endocrinological laboratory tests were not remarkable. Clinicians decided to observe the patient due to the risk of the tissue diagnosis. She was discharged without any treatment recommended for follow up at an outpatient clinic of another hospital. During follow up at an outpatient clinic, she visited our emergency room due to headache and an episode of syncope. The patient was referred to the neurosurgical department for evaluation of a mass lesion in the pituitary stalk and infundibular recess. MRI demonstrated a suprasellar mass measuring about 1 x 1 cm in size. The lesion showed iso-signal intensity on precontrast T1-weighted image with strong homogeneous enhancement by gadolinium (Figure A and B). Initially, we were highly suspicious of lymphoma or metastasis. We performed endoscopic biopsy because the tumor was located within the infundibular recess of the third ventricle. After the tumor wall was coagulated with unipolar coagulator, biopsy of multiple pieces was performed.
GROSS AND MICROSCOPIC PATHOLOGY
On endoscopic view, a reddish, well-circumscribed mass from the infundibular recess protruded into the third ventricle was not adhered to the optic chiasm (Figure C). The tumor appeared highly vascular. Microscopically, the majority of the tumor showed a lobular proliferation of closely packed, thin-walled capillaries that did not show any malignant tumor cells (Figures D and E). Differential diagnosis for solid- and low-grade tumors originating in the infundibular recess and pituitary stalk should be included granular cell tumor and pituicytoma. The tumor cells did not exhibit immunoreactivity for CD68 (KP-1) and S100 protein (Figures F and G) and were negative for glial fibrillary acidic protein (GFAP). Spindle cells were not demonstrated in the tumor.