Endocrine Abstracts

JOINT3660

Introduction: Arachnoid cyst is a rare condition characterized by the accumulation of fluid in the subarachnoid space, located between the membranes surrounding the brain and spinal cord. This condition can lead to compression of brain structures and disrupt the functioning of the pituitary gland, resulting in hormonal production abnormalities. In some cases, hormonal disorders, such as corticotropic insufficiency, can be the first clinical sign revealing an arachnoid cyst.

Observation: We report the case of a 56-year-old woman with no notable medical history, who consulted for intense asthenia, headaches, and slight weight gain. Biological tests revealed low TSH, low FT4 and FT3 levels, and a decreased 8 a.m. cortisol, suggesting corticotropic insufficiency. Pituitary MRI showed an arachnoid cyst associated with atrophy of the anterior pituitary, confirming hypothalamo-pituitary dysfunction. Substitution treatment with hydrocortisone and Levothyrox was initiated, with gradual dose increases. This treatment led to regression of symptoms and a significant improvement in the patient’s quality of life.

Discussion: Arachnoid cyst is a rare and often underdiagnosed condition, characterized by abnormal accumulation of fluid in the subarachnoid space. This accumulation can exert pressure on brain structures, particularly the pituitary gland, leading to hypothalamo-pituitary dysfunction. Clinical manifestations can vary, with corticotropic insufficiency being a significant feature. The uniqueness of this case lies in the reversibility of corticotropic insufficiency after substitution therapy. This reversibility, though rare, suggests that mechanical compression of the pituitary gland does not necessarily lead to irreversible damage. It opens up interesting perspectives on the underlying pathophysiological mechanisms, such as transient hypoxia, disruption of neuroendocrine signaling, or the plasticity of pituitary cells.

Conclusion: Arachnoid cyst, although rare, can lead to severe hormonal disorders, which may sometimes be reversible. Early diagnosis, along with appropriate management and careful follow-up, is essential to optimize clinical outcomes and improve patients’ quality of life.