59‐YEAR OLD FEMALE WITH SUPRASELLAR MASS

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 (0.7 ng/dL). Because she was postmenopausal, LH (1.76 mIU/mL) and FSH (1.02 mIU/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 × 1 cm in size. The lesion showed iso‐signal intensity on precontrast T1‐weighted image with strong homogeneous enhancement by gadolinium (1, 2). 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.

Figure 1.

Figure 2.

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 3). 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 (4, 5). 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 (6, 7) and were negative for glial fibrillary acidic protein (GFAP). Spindle cells were not demonstrated in the tumor.

Figure 3.

Figure 4.

Figure 5.

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Figure 7.

What is the diagnosis?

DIAGNOSIS

Capillary hemangioma.

DISCUSSION

The majority of capillary hemangiomas arise in the skin, scalp, or oral mucosa and typically appear within a few months of birth (9). In these areas, such lesions have been reported to occur in 1.1 to 2.6% of full‐term neonates, with an estimated frequency of 10 to 12% within the first year of life. They typically demonstrate rapid growing up to 6 to 8 months, followed by a plateau phase between 8 and 12 months. Occasionally, these lesions are completely regressed in 5 years (5). The natural history of capillary hemangiomas occurring outside the central nervous system has been well characterized by proliferative and involutional phases (4). Only 14 microscopically proven cases have been reported in the literature. Capillary hemangiomas are believed pathologically to be hamartomatous proliferations of vascular endothelial cells. Histologically, a capillary hemangioma is composed of capillary‐size vessels lined by a single layer of benign endothelial cells (10). Blood vessels vary widely in size from small lumina lined with plump endothelial cells to dilated vessels lined with flattened endothelium (1). GFAP immunostaining showed no glial tissue present within the lesions (2). Microscopically, capillary hemangiomas in the central nervous system must be distinguished from highly vascular neoplasm, which include hemangioendotheliomas, hemangiopericytomas, and hemangioblastomas (7). In this case, histological examination failed to show large vacuolated stromal cells characteristic of capillary hemangioblastomas, primitive vascular differentiation characteristic of hemangioendotheliomas and storiform architecture in hemangiopericytomas. Tumors occurring in the infundibular recess or pituitary stalk include pituitary adenomas, germ cell tumors, pituicytomas, and granular cell tumors. Pituicytomas are noninfiltrative sellar or parasellar tumors arising from the neurohypophysis. Pituicytoma is derived from pituicyte, which is a specific glial cell that accounts for the majority of nucleated cells in the neurohypophysis. Pituicytes have been identified as GFAP positive, spindle, or stellate cells (8). Granular cell tumors are composed of densely packed polygonal cells with eosinophilic, granular, diastase‐resistant cytoplasm and perivascular lymphocytic aggregates are a common feature (3). These tumors typically express S100 protein and CD68 (KP‐1) (6). Only thin‐walled capillaries were demonstrated in this case that was negative for S100 protein, CD68 (KP‐1) and GFAP. In summary, we have reported on a capillary hemangioma in the infundibular recess and pituitary stalk. Capillary hemangiomas should be included as a rare differential diagnosis in patients with well‐enhanced homogeneous lesions in the infundibular recess and pituitary stalk.

ABSTRACT

Intracranial capillary hemangiomas are extremely rare. Only 14 histologically proven cases have been reported in the literature. A 59‐year‐old‐female presented with a severe headache for 3 weeks. Brain MRI revealed a homogeneous contrast enhancing round mass lesion in the pituitary stalk and infundibular recess. We performed endoscopic biopsy. In the operative field, a reddish, well‐circumscribed mass from the infundibular recess protruded into the third ventricle and it was separated from the optic chiasm. The tumor appeared a highly vascular. Histopathological examination demonstrated an aggregation of thin‐walled capillaries, consistent with capillary hemangioma.