Uncommon Presentation of Pituitary Macroadenoma: A Case of Hemichiasmal Field Defect

Abstract

Background:

Pituitary macroadenomas are benign tumors of the anterior pituitary gland, commonly presenting with visual disturbances due to their proximity to the optic pathways. While bitemporal hemianopia is a well-known manifestation, hemichiasmal field defects are less commonly reported. This case highlights the significance of recognizing such visual field defects as potential early indicators of underlying pituitary pathology.

A 27-year-old male patient presented to the Ophthalmology department with a two-month history of visual field defects. Perimetry was performed, revealing a hemichiasmal field defect. Subsequent magnetic resonance imaging (MRI) was conducted to evaluate the sellar and suprasellar regions for potential compressive lesions. Hormonal assays were also planned to assess for endocrine dysfunction associated with pituitary tumors.

MRI findings demonstrated a well-defined T1/T2 hyperintense lesion in the sellar, suprasellar, and predominantly left parasellar regions, consistent with a pituitary macroadenoma. The visual field defect confirmed the involvement of the optic chiasm, necessitating further evaluation and potential surgical intervention.

Conclusion

This case underscores the importance of recognizing hemichiasmal field defects as significant clinical signs of pituitary macroadenomas. Early diagnosis through comprehensive evaluation and appropriate imaging is crucial for timely intervention, which can significantly improve patient outcomes and prevent irreversible visual impairment. A multidisciplinary approach involving both Ophthalmology and Neurology is essential in managing such cases effectively