Introduction Phaeochromocytoma, a catecholamine-producing endocrine tumour, is a life-threatening condition to the mother and fetus. The incidence of phaeochromocytoma in pregnancy is extremely rare, 1 in 54 000 pregnancies¹. If it remains undiagnosed and untreated, maternal and fetal mortality amounts to 40–50%^{2 3}. Classically, physicians search for the tumour in hypertensive patients with paroxysmal symptoms such as headache, sweating or palpitations. However, our patient presented atypically and would have been left undiagnosed.

Case presentation A 21-year-old presented after a fall at 24 weeks gestation, with loin pain on the contralateral side to the fall. This prompted an ultrasound scan that demonstrated a 9 cm ‘haematoma’ above the right kidney. As she was claustrophobic, she declined magnetic resonance imaging (MRI). A repeat ultrasound was performed which showed the mass to be unchanged. Suspicion arose and an MRI under sedation was performed (as recommended to look for adrenal/renal mass in pregnancy⁴). This confirmed an 8 cm × 7 cm mass superior to the right kidney. An endocrinologist reviewed her and serum and urine biochemistry investigations were performed.

Her urinary 3-methoxytyramine and serum dopamine levels were raised^{5 6} indicating possible phaechromocytoma. She did not need α-adrenoceptor blockade, as she remained asymptomatic throughout her pregnancy. She was referred to a tertiary hospital where an elective Caesarean section and surgical tumour removal were performed simultaneously.

Conclusion Diagnosing phaeochromocytoma in an asymptomatic pregnant patient is challenging. However, when diagnosed, a multi-disciplinary team approach (obstetrician, surgeon and endocrinologist) is vital in the management of this rare disorder.

References

1. Lenders JWM. Phaeochromocytoma and pregnancy: a deceptive connexion. European Journal of Endocrinology 2012;161:143–150.

2. Schenker JG & Chowers I. Phaeochromocytoma and pregnancy. Review of 89 cases. Obstetrical and Gynecological Survey 1971;26:739–747.

3. Dean RE. Phaeochromocytoma and pregnancy. Obstetrics and Gynecology 1958;11: 35–42.

4. Lenders JW, Eisenhofer G, Mannelli M, et al. Phaeochromocytoma. Lancet 2005;366:665–675.

5. Peleg D, Munsick RA, Diker D, Goldman JA & Ben-Jonathan N. Distribution of catecholamines between fetal and maternal compartments during human pregnancy with emphasis on L-dopa and dopamine. Journal of Clinical Endocrinology and Metabolism 1986;62:911–914.

6. Lenders JW, Pacak K, Walther MM, Linehan WM, Mannelli M, Friberg P, Keiser HR, Goldstein DS & Eisenhofer G. Biochemical diagnosis of phaeochromocytoma: which test is best? Journal of the American Medical Association 2002;287: 1427–1434.