Fever of Unknown Origin: Could It Be a Pheochromocytoma? A Case Report and Review of the Literature

Table 1

Comparison of our case with other reports of pheochromocytoma presenting as FUO.

Author and; Reference	Age at; diagnosis	Gender	Duration of; fever	Clinical symptoms and signs other than fever	Initial labs: Metanephrines/Catecholamines/; Interleukin-6 [IL-6]	ESR	CRP	Size of mass	Diagnoses and management
Martin et al. [5]	57 years	Male	3 months	Hypertension, tachycardia, nausea, pallor	Free normetanephrine: 4.82 nmol/L [<0.90] & metanephrine 4.03 nmol/L [<0.50]	Elevated	Elevated	4.5 cm right adrenal mass	Right adrenalectomy with clinical improvement
K F Ng [6]	7 years	Male	40 days	Absent hypertension, tachycardia	Not done, as pheochromocytoma not suspected		Elevated	5 cm left adrenal mass	Surgical resection consistent with a pheochromocytoma, followed by clinical improvement
Ciacciarelli et al. [7]	45 years	Female	2 months	Hypertension & tachycardia; Absent palpitations, headache, diaphoresis.	Urine and plasma metanephrines normal.; Interleukin-6: 180.28 pg/mL (3-4)	Elevated	Elevated	3.5 cm left adrenal mass	Left adrenalectomy with clinical improvement
Jin et al. [8]	66 years	Male		Hypertension, tachycardia, renal failure	24 hr urine vanillylmandelic acid: 14.3 µmol (9.6–49.5)		Elevated	7 cm left adrenal mass	Left adrenalectomy with clinical improvement and improvement in renal function
Yarman et al. [9]	18 years	Female		Weight loss, malaise; Absent paroxysmal symptoms	Urine normetanephrine: 3612 µg/24 hours (105–354); Interleukin-6: 12.5 pg/mL (<3.0 pg/mLl	Elevated	Elevated	5.5 cm right adrenal mass	Surgical resection, followed with clinical improvement; Interleukin-6 normalized a few weeks after resection
Our patient	64 years	Female	1 month	Sweating, headaches, hypertension, malaise	24-hour urine normetanephrine 1915 mcg (122-676)	Elevated	Elevated	5 cm left adrenal mass	Left adrenalectomy with clinical improvement