The immune cell infiltrate in the tumour microenvironment of phaeochromocytomas and paragangliomas.

Emerging evidence suggests the composition of the tumour microenvironment (TME) correlates with clinical outcome and that each tumour type has a unique TME including a variable population of inflammatory cells. We performed immunohistochemistry on 65 phaeochromocytoma and paraganglioma (PPGL) tumour samples with 20 normal adrenal medulla samples for comparison. The immune cells assessed were macrophages, lymphocytes and neutrophils, and we compared the proportion of infiltration of these immune cells with clinical and histopathological factors. There was a higher proportion of immune cells in tumour tissue compared to non-neoplastic adrenal medulla tissue, with a predominance of macrophages. There was a higher proportion of M2:M1 macrophages and T-helper lymphocytes in aggressive tumours compared to indolent ones. For SDHB-associated tumours, there was a higher proportion of M2 macrophage infiltration, with higher M2:M1 in aggressive SDHB PPGLs compared to indolent tumours. These data demonstrate that immune cells do infiltrate the TME of PPGLs, confirming that PPGLs are immunologically active tumours. Differences in the TME of PPGLs were observed between aggressive and indolent tumours. These differences could potentially be exploited as an aid in predicting tumour behaviour.

Clinical outcomes following unilateral adrenalectomy in patients with primary aldosteronism.

BACKGROUND: In approximately half of cases of primary aldosteronism (PA), the cause is a surgically-resectable unilateral aldosterone-producing adrenal adenoma. However, long-term data on surgical outcomes are sparse. AIM: We report on clinical outcomes post-adrenalectomy in a cohort of patients with PA who underwent surgery. DESIGN: Retrospective review of patients treated for PA in a single UK tertiary centre. METHODS: Of 120 consecutive patients investigated for PA, 52 (30 male, median age 54, range 30-74) underwent unilateral complete adrenalectomy. Blood pressure, number of antihypertensive medications, and serum potassium were recorded before adrenalectomy, and after a median follow-up period of 50 months (range 7-115). Recumbent renin and aldosterone were measured, in the absence of interfering antihypertensive medication, ≥3months after surgery, to determine if PA had been biochemically cured. RESULTS: Overall, blood pressure improved from a median (range) 160/95 mmHg (120/80-250/150) pre-operatively to 130/80 mmHg (110/70-160/93), P < 0.0001. 24/52 patients (46.2%) had cured hypertension, with a normal blood pressure post-operatively on no medication. 26/52 (50%) had improved hypertension. 2/52 patients (3.8%) showed no improvement in blood pressure post-operatively. Median (range) serum potassium level increased from 3.2 (2.3-4.7) mmol/l pre-operatively to 4.4 mmol/l (3.3-5.3) post-operatively, P < 0.0001). Median (range) number of antihypertensive medications used fell from 3 (0-6) pre- to 1 post-operatively (range 0-4), P < 0.0001. CONCLUSIONS: Unilateral adrenalectomy provides excellent long-term improvements in blood pressure control, polypharmacy and hypokalaemia in patients with lateralizing PA. These data may help inform discussions with patients contemplating surgery.