Summary

Multiple endocrine metastases are a rare but possible complication of lung adenocarcinoma (LAC). Pituitary metastasis is a rare condition with poor clinical expression. Diabetes insipidus (DI) is its most common presenting symptom. Here we report an original case of a pituitary stalk (PS) metastasis from LAC presenting as central DI followed by adrenal insufficiency (AI) from bilateral adrenal metastasis, without known evidence of the primary malignancy. A 45-year-old woman whose first clinical manifestations were polyuria and polydipsia was admitted. She was completely asymptomatic with no cough, no weight loss or anorexia. Chest radiography was normal. Brain MRI showed a thick pituitary stalk (PS). DI was confirmed by water restriction test and treated with vasopressin with great clinical results. Explorations for systemic and infectious disease were negative. Few months later, an acute AI led to discovering bilateral adrenal mass on abdominal CT. A suspicious 2.3 cm apical lung nodule was found later. Histopathological adrenal biopsy revealed an LAC. The patient received systemic chemotherapy with hormonal replacement for endocrinological failures by both vasopressin and hydrocortisone. We present this rare case of metastatic PS thickness arising from LAC associated with bilateral adrenal metastasis. Screening of patients with DI and stalk thickness for lung and breast cancer must be considered. Multiple endocrine failures as a diagnostic motive of LAC is a rare but possible circumstance.

Learning points:

• Adrenal metastasis is a common location in lung adenocarcinoma; however, metastatic involvement of the pituitary stalk remains a rare occurrence, especially as a leading presentation to diagnose lung cancer.

• The posterior pituitary and the infundibulum are the preferential sites for metastases, as they receive direct arterial blood supply from hypophyseal arteries.

• Patients diagnosed with diabetes insipidus due to pituitary stalk thickness should be considered as a metastasis, after exclusion of the classical systemic and infectious diseases.

• The diagnosis of an endocrinological metastatic primary lung adenocarcinoma for patients without respiratory symptoms is often delayed due to a lack of correlation between endocrinological symptoms and lung cancer.

• The main originality of our case is the concomitant diagnosis of both endocrinological failures, as it was initiated with a diabetes insipidus and followed by an acute adrenal insufficiency.

Learning points:

• Drug–drug interaction between ritonavir and triamcinolone can cause Cushing syndrome.

• Although triamcinolone has a half-life of 3 h, an intra-articular injection may be systematically absorbed for 3 weeks after injection, and adrenal suppression may last as long as 30 days.

• Co-administration of ritonavir and corticosteroids may result in an increase of plasma levels of corticosteroids levels, as they are both eliminated by CYP3A metabolism, and this interaction has the potential to prolong the half-life of triamcinolone several fold.

• No specific guidelines are available for the management of iatrogenic Cushing syndrome secondary to ritonavir and corticosteroids.

• One treatment option includes replacing ritonavir with a non-protease inhibitor-based regimen.

• Initiating hydrocortisone replacement therapy to prevent an adrenal crisis is also an alternate option.

Learning points

• Hypopituitarism may be the presenting symptom of lymphoma in the absence of associated overt symptoms or signs of a haematological malignancy resulting in delay in diagnosis and institution of treatment.

• Pituitary dysfunction due to tumour infiltration has a greater tendency to involve the posterior pituitary and infundibulum resulting in diabetes insipidus and hyperprolactinaemia compared with a non-functioning pituitary adenoma.

• The common associated symptoms of hypopituitarism due to lymphoma infiltration of the hypothalamic–pituitary system include painful ophthalmoplegia, cranial nerve palsies and constitutional symptoms.

• Radiological abnormalities of the hypothalamic–pituitary region are usually present and often associated with cavernous sinus or stalk involvement.

• With early institution of definitive treatment, both haematological response and improvement of pituitary dysfunction are expected although the reversal of hypopituitarism tends to be partial and delayed.

• A high index of suspicion of underlying malignancy such as lymphoma should be present in patients presenting with acute pituitary dysfunction associated with painful ophthalmoplegia, radiological features atypical of pituitary adenomas and constitutional symptoms to enable early diagnosis and prompt initiation of definitive therapy.

Learning points

• Standard-dose inhaled fluticasone can cause adrenal insufficiency.

• Adrenal insufficiency should be considered in patients taking, or who have recently discontinued, inhaled fluticasone therapy and present with new onset of nonspecific symptoms such as fatigue, weakness, depression, myalgia, arthralgia, unexplained weight loss, and nausea that are suggestive of adrenal insufficiency.

• Adrenal insufficiency should be considered in postoperative patients who exhibit signs of hypoadrenalism after fluticasone therapy has been withheld in the perioperative setting.

• Routine screening for hypoadrenalism in patients without clinical signs or symptoms of adrenal insufficiency after the discontinuation of inhaled fluticasone therapy is not indicated due to the apparently low incidence of adrenal insufficiency caused by fluticasone.