Pituitary metastasis of salivary gland carcinoma mimicking hypophysitis: A case report and literature review

INTRODUCTION: Pituitary metastases from salivary gland carcinomas are rare. Moreover, pituitary metastasis and hypophysitis exhibit neuroimaging similarities that complicate the diagnosis in patients receiving immune checkpoint drugs. PRESENTATION OF CASE: We present a case of pituitary metastasis derived from a sublingual gland carcinoma; this case posed a challenge in the differential diagnosis of hypophysitis. A 52-year-old male patient presented with anorexia and visual disturbances. The patient was previously diagnosed with sublingual gland carcinoma that necessitated surgical intervention consisting of tumor resection and residual lymph node dissection. Subsequently, the patient underwent immune checkpoint blockade therapy following platinum-based chemotherapy. Magnetic resonance imaging revealed the presence of an intrasellar tumor infiltrating the dura mater, cavernous sinus, and pituitary stalk with isointensity on T1 and T2 weighted images and homogeneous gadolinium enhancement. Despite the initial suspicion of hypophysitis, diagnostic treatment with systemic corticosteroids failed to induce significant tumor reduction. Diagnostic clarification was achieved via an endoscopic transsphenoidal biopsy, which confirmed the histological diagnosis of pituitary metastasis from the prior sublingual gland adenocarcinoma. Radiotherapy was administered as a therapeutic intervention. DISCUSSION: The case report highlighted the rarity of metastases from salivary gland carcinoma to the pituitary gland and emphasized the challenges in distinguishing between pituitary metastasis and hypophysitis based on imaging studies alone, particularly in patients receiving immune checkpoint inhibitors. CONCLUSION: Given the rarity of this condition and its neuroimaging similarities with hypophysitis, pathological confirmation is imperative for a definitive diagnosis.