When is a phaeo not a phaeo? Depression in an adolescent leading to a phaeochromocytoma-like biochemical profile

A previously healthy 14 4/12 year old boy presented with a 6 months history of a 10 kg weight loss, profuse sweating, fatigue, myalgia, sleep difficulties and loss of appetite. Other history was notable for ongoing feelings of sadness and anxiety, and three suicide attempts. On physical examination he was alert and oriented, his weight was 38.5 kg and his height 172 cm. The BMI SDS was −4.7. Blood pressure was 120/80 mm Hg and resting pulse was 130 bpm. He was sweating profusely, did not maintain eye contact, and was shivering. The remainder of his examination, including neurological was unremarkable. Diagnostic workup ruled out infectious and malignant causes. Thyroid function tests showed an increased fT4 level of 34.5 pmol/L (10–23), and a TSH level which was initially slightly low at 0.06 mIU/L (0.5–5.0), both of which normalized spontaneously in follow up tests. Medical psychiatry was also involved and provided supportive therapy and medication management. The sweating and resting tachycardia of 130 bpm prompted his primary team to perform an evaluation for pheochromocytoma with concerning results: his 24-hour urine collection revealed elevated dopamine and norepinephrine levels (Table 1). Table 1 Biochemical profile and clonidine suppression test results, and list of imaging studies performed To confirm the urinary catecholamine results and to localize the presumptive tumor, an extensive workup was carried out over the course of 1.5 years. Testing revealed a persistent elevation of urine catecholamines but negative anatomical and functional imaging studies (Table 1). In an effort to differentiate a true pheochromocytoma from a false positive elevation of catecholamines, a clonidine suppression test was carried out, which is reported to have 98%–100% specificity for pheochromocytoma, when positive.1 Our patient’s plasma normetanephrine and norepinephrine levels did not suppress sufficiently during the test, which was consistent with the presence of pheochromocytoma. During this test and the initial workup, the patient was not consuming any drugs or medication. Follow up imaging studies were carried out over the next 12 months and were still negative (Table 1). Genetic testing for pheochromocytoma was also performed including examination for mutations in ret proto-oncogene (RET), succinate dehydrogenase complex, subunit B (SDHB), von Hippel-Lindau tumor suppressor gene (VHL), which were also negative. In parallel to the medical workup, he was followed by medical psychiatry for his depression, anxiety and physical complaints. Two months after his initial presentation, the antidepressant Citalopram was prescribed, but the patient was poorly adherent and did not take the medication. Treatment with Fluoxetine was initiated seven months post presentation, with better adherence, and titrated up to 30 mg daily. He also underwent occupational and physical therapy. This led to some improvement in his mood, anxiety, somatic complaints and functioning, and a concomitant, progressive drop in his catecholamine levels, which on last measurement had normalized (Table 1).