Biochemically silent phaeochromocytoma presenting with non-specific loin pain

Abstract

A 55-year-old woman presented with a 4-month history of right-sided non-specific loin pain and 6 kg weight loss. A CT scan of the abdomen and pelvis showed an incidental 4.5 cm right-sided adrenal lesion which was not typical of an adrenal adenoma. This was further confirmed on MRI of the adrenals. Biochemical investigations to investigate for a functional adrenal lesion included serum catecholamines and metanephrines, an aldosterone to renin ratio and an overnight dexamethasone suppression test. These were all negative. A laparoscopic adrenalectomy was performed in view of the large size of the lesion. Histology was consistent with a phaeochromocytoma, which confirmed the diagnosis of a non-secreting phaeochromocytoma. Non-secreting phaeochromocytomas are rare and usually found in patients with known genetic mutations. Adrenal lesions not related to any mutations similar to our case are even rarer and reported even less in the literature.

Silent pheochromocytoma and paraganglioma: Systematic review and proposed definitions for standardized terminology

“…In addition to the term “clinically silent” to define the absence of signs and symptoms, other terms were used based on biochemistry. In particular, 55 cases were defined by the authors as “biochemically silent” ( 4 , 11 , 16 , 18 , 21 , 22 , 58 – 64 ), 59 as “non-functional” ( 6 – 8 , 17 , 19 , 35 – 39 , 41 – 50 , 52 – 54 , 65 – 89 ) and two as “non-secretory” PPGL ( 9 , 10 ) and 7 patients presented “negative markers” ( 90 ).…”

“…Among 55 cases defined by the authors as “biochemically silent”, test results of plasma metanephrines with respective reference intervals were available in only 15 cases ( 11 , 22 , 58 , 59 , 64 ) ( Table 2 ). Among those 15 cases, test results and reference intervals for plasma catecholamines and metanephrines were reported in five cases ( 11 , 58 ) and for urinary metanephrines (+/- catecholamines) in 25 cases ( 16 , 21 , 22 , 58 , 59 , 61 , 63 , 64 ). All plasma results showed values below upper cut-offs of stipulated reference intervals.…”

“…Review of the literature shows that patients with PPGLs and negative biochemical test results are often defined to have “biochemically silent” tumors ( 4 , 11 , 16 , 18 , 21 , 22 , 58 – 63 ). In most of the aforementioned studies, the authors define PPGLs as “biochemically silent” according to measurements of catecholamine-related biomarkers that do not exceed the upper cut-offs.…”

“…In other cases, use of the terms “silent” and “non-functioning” tumors have been employed equivalently to describe patients with PPGL who present without signs and symptoms but in whom it is not always clear whether the tumors produce catecholamines ( 6 – 8 ). In other cases, the term “non-secretory” or “non-secreting” has been employed to designate patients with absence of secretory symptoms or lack of functional activity ( 9 – 11 ). Appropriate definitions according to the ability of the tumors to synthesize catecholamines (functional/non-functional), release catecholamines (secretory/non-secretory) or according to the presence of positive or negative biochemical test results (biochemically positive/negative) are essential for scientific communication.…”