Lymphocytic hypophysitis with associated thyroiditis in a man with aseptic meningitis.

OBJECTIVE: Lymphocytic hypophysitis (LH) is a rare chronic inflammatory disorder characterized by lymphocytic infiltration of the pituitary gland commonly affecting women during pregnancy or post-partum period. The pathogenesis remains uncertain, however an autoimmune process is frequently implicated. There is limited data on the occurrence of LH outside the setting of autoimmunity. CASE: We describe a 37-year-old man presenting with diarrhoea, nausea, weight loss, low-grade fever, headache and cerebrospinal fluid analysis consistent with aseptic meningitis. Magnetic resonance imaging (MRI) demonstrated a homogenously enlarged pituitary gland with biochemical testing revealing partial hypopituitarism with adenocorticotrophic hormone and gonadotrophin deficiency. Notably, his free thyroid hormone levels were elevated with a suppressed thyroid-stimulating hormone and a suppressed thyroid technetium scan consistent with thyroiditis. Tissue antibodies including thyroid antibodies were negative. Following introduction of hydrocortisone, he developed transient diabetes insipidus which spontaneously resolved after 4 months. Thyrotoxicosis resolved after 5 weeks and thyroxine was commenced as he developed secondary hypothyroidism. Repeat MRI 3 months later showed a reduction in the size of the pituitary gland which by 6 months had returned to normal size. He remains well on hydrocortisone, thyroxine and testosterone replacement.
CONCLUSIONS: Based on clinical and radiological grounds, the diagnosis was consistent with lymphocytic hypophysitis associated with subacute thyroiditis. This is only the second report of this combination in the absence of autoimmunity and the first report of LH and thyroiditis with associated aseptic meningitis in the absence of tissue autoantibodies. We propose a possible viral illness as the unifying aetiological cause.