© 2008 Ozkaya et al; licensee BioMed Central Ltd.Introduction: Adrenal incidentaloma can be described as adrenal lesions that are incidentally diagnosed during abdominal laparotomy or any abdominal screening without prior suspicion of adrenal disease. It is important to diagnose adrenal lesions to learn if they are hormonally active or malignant. The most common clinical sign of pheochromocytoma is sustained or paroxysmal hypertension, and the most common symptoms are headache, excessive truncal sweating, and palpitation. In some cases, the clinical symptoms are not clear. Roughly 70% of adrenal incidentalomas are non-functional. A small group of 5-7% of the functional ones (30%) may exist as pheochromocytoma. Ten percent of pheochromocytoma cases are diagnosed incidentally during computed tomography (CT) or magnetic resonance imaging (MRI) screenings for other reasons. The most frequent symptom of the pheochromocytoma is hypertension, and 90-100% of cases exhibit it. The literature indicates that incidental pheochromocytoma cases that are smaller than 1 cm have no clinical symptoms. Rarely, some large pheochromocytoma cases do not show any clinical symptoms, and it is difficult to diagnose very small ones.Case presentation: A 45-year-old male patient experienced an epigastric ache and distended stomach for 7 years. The serum cortisol level was 19.2 ng/dL (normal range: 5-20 ng/dL), and urinary free cortisol excretion was 25.00 μg/24 h (normal range:10.00-100.00 μg/24 h). The serum basal level of adrenocorticotropic hormone (ACTH) was 21 pg/mL (normal range: 9 to 52 pg/mL). Plasma cortisol was under 1.00 μg/dL after low dose (1 mg) overnight dexamethasone suppression test. 24 hours urinary catecholamines level were vanil mandilic acid (VMA) 8.90 mg/day (normal range, 3 to 90 mg/day), metanefrin 330 μg/day (normal range, 52 to 341 μg/day), epinefrin 13 μg/day (normal range, 2 to 24 μg/day), norepinefrin 41 μg/day (normal range; 15 to 100 μg/day). During abdominal ultrasonography (USG), a tumor was diagnosed in the right perirenal space. A regular-shaped mass (dimension 36 × 35 × 35 mm) with a homogeneous and solid structure was diagnosed in CT. The density of the mass was 80 Hounsfield units (HU) in postcontrast CT. The patient was given a diagnosis of a non-functional adrenal incidental lesion, underwent a right adrenalectomy. Histopathological data correlated with pheochromocytoma as well.Conclusion: Pheochromocytoma can be diagnosed by establishing an increase in catecholamines and metabolites in the plasma and urine. The level of catecholamines and metabolites in the plasma and urine provide 95% of the evidence of the disease. Because the dimensions of the lesion were large and the HU was very clear, the patient was underwent surrenalectomy. During laboratory investigation, there was no evidence of abnormality; we, therefore, think that these cases can be named sublaboratory pheochromocytoma.