Rare infundibular tumors: clinical presentation, imaging findings, and the role of endoscopic endonasal surgery in their management

Abstract

Background The spectrum of infundibular lesions is broad and distinct from sellar pathologies. In many cases, histology is needed to establish the correct diagnosis and determine the treatment approach. Methods Medical files of eight patients with distinct infundibular tumors were reviewed. Histopathologically confirmed diagnosis included three pituicytomas, three granular cell tumors, and two pilocytic astrocytomas. Results Patients shared similar imaging findings and clinical symptoms, including visual impairment (n = 5), hypopituitarism (n = 4), and headache (n = 4); one patient presented with disseminated disease and symptoms from spinal metastases. All the pituicytomas, two granular cell tumors, and one infundibular pilocytic astrocytoma case underwent endoscopic endonasal surgery; gross total resection was achieved in five patients, three developed postoperative diabetes insipidus, and two developed hypopituitarism. No recurrences were observed. One granular cell tumor patient was treated with gamma-knife radiosurgery after stereotactic biopsy; the tumor remained stable in size for over 9 years. The infundibular pilocytic astrocytoma patient who presented with spinal metastases received radiotherapy and systemic chemotherapy. The overall mean follow-up period was 25.1 months. Conclusion Infundibular tumors are rare entities that represent a diagnostic challenge. Histopathological examination is essential for definitive diagnosis. Surgery, radiation therapy, and chemotherapy all have a role in the management of these tumors.

Keywords: endoscopic endonasal approach; granular cell tumor; pilocytic astrocytoma; pituicytoma; radiation therapy.

Fig. 1

Pituicytomas. Patient 1: preop midline magnetic resonance imaging (MRI) (left) showing a rounded suprasellar mass and postop (right) MRI after endoscopic endonasal approach (EEA) and gross total resection of the tumor (A). Patient 2: preop (left) and postop (right) computed tomography (CT) demonstrating the gross total resection of the pituicytoma (B). Patient 3: preop midline MRI (left) illustrating a heterogeneous suprasellar tumor which was totally resected with the EEA as showed on the postop MRI (right; C).

Fig. 2

Granular cell tumors. Patient 4: magnetic resonance imaging (MRI) after stereotactic biopsy of the midline suprasellar mass (left); the patient was treated with gamma-knife radiosurgery and the tumor remained stable in size for over 9 years. In the most recent MRI (right), a slight increase in tumor volume had been observed (A). Patient 5: preop midline MRI (left) showing a rounded suprasellar mass; a less aggressive surgical resection with the endoscopic endonasal approach was employed and subtotal tumor resection was achieved (right) with preservation of pituitary function (B). Patient 6: preop (left) and postop (right) midline MRIs showing the location of the tumor and the gross total resection following endoscopic endonasal surgery (C).

Fig. 3

Infundibular pilocytic astrocytoma. Patient 8: preop midline magnetic resonance imaging (left) illustrating the solid infundibular mass; the patient underwent endoscopic endonasal approach and gross total resection of the tumor was achieved (right). The increased linear enhancement over the sellar fossa and the planum represents the vascularized nasoseptal mucosal flap which is used for reconstruction.

Fig. 4

Infundibular pilocytic astrocytoma, disseminated disease. Patient 7: midline magnetic resonance imaging (MRI) of the head (left) shows an infundibular mass measuring 11 mm in its maximum diameter; spinal MRI (right) illustrating concomitant lesions of the thoracic spine (arrows) which were considered to represent cerebrospinal fluid “drop” metastases.

Fig. 5

Endoscopic resection of a pituicytoma (patient 2). Upper: intraoperative view with a 0-degree endoscope showing the pituitary gland (PG) and the tumor (Tu) after opening of the suprasellar dura (D). Initial tumor debulking has taken place in the midline, in between the pituitary stalk (S), which was split in the midline by the tumor. The bone remover over the sella and tuberculum sella has been extended laterally exposing both cavernous sinuses (CS). Lower: intraoperative view during tumor (Tu) removal with the two suctions technique. The PG is protected with the intact dura. At the superior aspect of the tumor, the right SHA ([R]SHa) is identified lying just beneath the optic chiasm (not shown).

Fig. 6

Intraoperative view of the third ventricle opening with a 0-degree endoscope after total tumor resection (patient 2). The tumor was extended up to the anterior recess of the third ventricle (3rd V), which was opened to achieve complete resection. The optic chiasm (OCh) is totally decompressed. The pituitary gland (PG) is hung from the preserved split stalk (S). Regardless of the anatomical preservation of the infundibulum, its function was lost.