Endocrine Abstracts

Phaeochromocytoma is a catecholamine producing tumour arising from the adrenomedullary chromaffin cells. It produces hormones such as epinephrine, norepinephrine, catecholamine and dopamine. (1) There have been some case reports describing an association between Brown adipose tissue (BAT) accumulation due to catecholamine excess caused by a phaeochromocytoma. We present a similar case in this abstract. A 77 year old lady was referred to the community geriatricians with symptoms of profuse sweating, difficulty walking, increase in abdominal girth, weight loss of 4–5 stones over the previous 4 months, abdominal pain, poor appetite and insomnia. Past medical history included bronchiectasis, Type 2 Diabetes, previous neck of humerus fracture, and pulmonary embolism. A CT chest, abdomen and pelvis showed an ill-defined heterogenous right peri-renal/retroperitoneal mass of fat and soft tissue density, and a 3.2 cm left adrenal enhancing mass. Urine normetadrenaline was raised at 11.21 umol/24hours (Normal Range <3). She was discussed in Urology and adrenal MDTs who felt there was a high likelihood of abdominal malignancy. Subsequently, a core biopsy of the right retroperitoneal mass was carried out to further classify it. She was treated with an alpha-blocker and this dramatically improved her symptoms but the abdominal discomfort remained. She then underwent an ultrasound guided biopsy of this mass. Histology showed adipocytes with multi-vacuolated cytoplasm and central nuclei consistent with brown fat. She subsequently underwent an elective laparoscopic adrenalectomy. A left adrenal mass was localised and removed. Histology of this lesion confirmed a phaeochromocytoma with positive immunohistochemical staining for CD56, chromogranin and synaptophysin with a maximum PASS score of 2. She made an unremarkable recovery post operatively. Her catecholamine levels and her blood pressure normalised post-surgery. A subsequent CT done eight week postoperatively showed a dramatic generalised reduction in the bulk, vascularity and density of the retroperitoneal brown fat with no local recurrence. The patient has reported a dramatic improvement in both her generalised and abdominal symptoms. Her diabetes has also resolved postoperatively. In summary, this case highlights the association between BAT and phaeochromocytoma. It has been hypothesized that catecholamine excess leads to a proliferation of BAT. The presence of clinical symptoms of tachycardia, weight loss, persistent sweats should prompt investigations for an underlying phaeochromocytoma. However, the presence of co-existent abdominal masses on imaging may suggest the possibility of excess BAT accumulation and should not be automatically assumed to be a primary or secondary malignancy.

Reference

1. https://academic.oup.com/jcem/article/99/6/1915/2537399