The Great Imitator in Endocrinology: A Painful Hypophysitis Mimicking a Pituitary Tumor

The incidence of syphilis has been increasing in recent decades in Western countries. Pituitary involvement is very unusual in syphilis. This infectious disease is not often considered in the workup of a patient with hypophysitis.

We report the case of a 28-year-old man who was admitted for headaches worsening over 1 month that became resistant to paracetamol. A magnetic resonance imaging scan revealed a heterogeneous pituitary mass suggesting a pituitary tumor. Hormonal investigations showed partial corticotropic and thyrotropic deficiencies. Headaches required high doses of morphine. Transsphenoidal surgery was performed, and histological examination revealed an aspect of hypophysitis. One month later, clinical reexamination showed skin and tongue lesions very suggestive of a syphilis infection, which was serologically confirmed. Immunohistochemistry on paraffin sections of the resected pituitary revealed an abundant presence of Treponema pallidum, confirming the diagnosis of a syphilitic hypophysitis. Intravenous therapy by benzylpenicillin for 14 days was rapidly efficient. Headaches stopped within a few days, and the skin and tongue lesions disappeared during the following month. Thyrotropic deficiency resolved in 2 weeks, but partial corticotropic deficiency persisted at 3 months.

This is the first case of a pituitary involvement in acquired syphilis, pathologically proven, in a non-HIV-infected patient. In a context of the resurgence of syphilis, this diagnosis should be considered in the case of a pituitary lesion with unusually intense headaches.