Hypophysitis is a rare inflammatory disorder of the pituitary gland, with an estimated incidence of 1 in 9 million. It is histologically classified into lymphocytic, granulomatous, xanthomatous, necrotizing, IgG4-related, or mixed subtypes. Mixed lymphocytic and granulomatous hypophysitis is uncommon, with a few cases reported worldwide.

This is a case of a 59-year-old Filipino woman who presented with a two-month history of progressive blurring of vision and intermittent headaches. MRI of the pituitary revealed a heterogeneously enhancing lobulated mass measuring 1.5cm × 1.7cm × 1.2 cm, initially suggestive of a pituitary macroadenoma. Laboratory evaluation demonstrated central adrenal insufficiency, hypothyroidism, hypogonadism, and growth hormone deficiency. She underwent transsphenoidal resection of the mass and histopathologic examination showed an admixture of lymphocytes and poorly formed granulomas confirming a diagnosis of mixed lymphocytic and granulomatous hypophysitis. Postoperatively, the patient was maintained on prednisone and levothyroxine replacement therapy and remained clinically stable three months after surgery.

Mixed lymphocytic and granulomatous hypophysitis may exist in rare conditions. The relationship between the two however remains unclear, but some authors propose these subtypes may belong to a spectrum of the same autoimmune disease with lymphocytic hypophysitis occurring earlier and eventually develop into a granulomatous hypophysitis later. This case may represent a transitional stage between the two histological patterns. Clinical and radiologic findings are often indistinguishable from pituitary adenomas or sellar masses hence posing as a diagnostic challenge without histopathologic confirmation. Hypophysitis probably secondary to an infectious or idiopathic cause is considered in this case since she had fever. However, she had no history of chronic cough, weight loss, or other pertinent systemic manifestations. Her complete blood count, urinalysis, chest X-ray ANA tests were unremarkable. Pituitary tuberculosis is quite rare with incidence of 4% but cannot be totally ruled out. Conservative management with steroids is the mainstay treatment of Hypophysitis but surgery may be indicated if there is presence of serious and progressive deficits of visual fields, visual acuity, or ocular movements that are not responsive to medical treatment.

Hypophysitis, though rare, should be considered in the differential diagnosis of pituitary masses associated with hypopituitarism to prevent unnecessary surgery and guide appropriate medical management.