A Branching Algorithm

Computed tomography (CT) of the abdomen and pelvis with oral and intravenous contrast revealed a 5 cm heterogeneous enhancing mass associated with the prostate gland extending into the base of the bladder. The mass obstructed the right renal collecting system and ureter causing severe right-sided ureterectasis and hydronephrosis. There was also 2.8 cm right-sided paracaval lymph node enlargement and 2.1 cm right-sided and 1.5 cm left-sided external iliac lymph node enlargement (Figure 1). There were no adrenal masses.

He is young for prostate, bladder, or colorectal cancer, but early onset variations of these tumors, along with metastatic testicular cancer, must be considered for the pelvic mass and associated lymphadenopathy. Prostatic masses can be infectious (eg, abscess) or malignant (eg, adenocarcinoma, small cell carcinoma). Additional considerations for abdominopelvic cancer are sarcomas, germ cell tumors, or lymphoma. A low aldosterone-renin ratio coupled with a normal potassium level makes primary aldosteronism unlikely. The normal angiography excludes renovascular hypertension.

His abdominal pain and gastrointestinal symptoms could arise from irritation of the bowel, distension of the right-sided urinary collecting system, or products secreted from the mass (eg, catecholamines). The hyperdynamic precordium, elevated ejection fraction, and murmur may reflect augmented blood flow from a hyperadrenergic state. A unifying diagnosis would be a pheochromocytoma. However, given the normal appearance of the adrenal glands on CT imaging, catecholamines arising from a paraganglioma, a tumor of the autonomic nervous system, is more likely. These tumors often secrete catecholamines and can be metastatic (suggested here by the lymphadenopathy). Functional imaging or biopsy of either the mass or an adjacent lymph node is indicated. However, because of the possibility of a catecholamine-secreting tumor, he should be treated with an alpha-adrenergic receptor antagonist before undergoing a biopsy to prevent unopposed vasoconstriction from catecholamine leakage.

Scrotal ultrasound revealed no evidence of a testicular tumor. Lactate dehydrogenase (LDH) was 179 IU/L (normal, 120-240 IU/L) and prostate specific antigen (PSA) was 0.7 ng/mL (normal, <2.5 ng/mL). The patient was given amlodipine and labetalol with improvement of blood pressures to 160s/100s. His creatinine decreased to 1.1 mg/dL. He underwent CT-guided biopsy of a pelvic lymph node. CT of the head without intravenous contrast demonstrated no intracranial abnormalities. His headache resolved with improvement in blood pressure, and he had minimal gastrointestinal symptoms during his hospitalization. No stool studies were sent. A right-sided percutaneous nephrostomy was placed which yielded >15 L of urine from the tube over the next four days.

Upon the first episode of micturition through the urethra four days after percutaneous nephrostomy placement, he experienced severe lightheadedness, diaphoresis, and palpitations. These symptoms prompted him to recall similar episodes following micturition for several months prior to his hospitalization.

It is likely that contraction of the bladder during episodes of urination caused irritation of the pelvic mass, leading to catecholamine secretion. Another explanation for his recurrent lightheadedness would be a neurocardiogenic reflex with micturition (which when it culminates with loss of consciousness is called micturition syncope), but this would not explain his hypertension or bladder mass.

Biochemical tests that were ordered on admission but sent to a reference lab then returned. Plasma metanephrine was 0.2 nmol/L (normal, <0.5 nmol/L) and plasma normetanephrine 34.6 nmol/L (normal, <0.9 nmol/L). His 24-hour urine metanephrine was 72 ug/24 hr (normal, 0-300 ug/24 hr) and normetanephrine 8,511 ug/24 hr (normal, 50-800 ug/24 hr).

The markedly elevated plasma and urine normetanephrine levels confirm a diagnosis of a catecholamine-secreting tumor (paraganglioma). The tissue obtained from the CT-guided lymph node biopsy should be sent for markers of neuroendocrine tumors including chromogranin.

Lymph node biopsy revealed metastatic paraganglioma that was chromogranin A and synaptophysin positive (Figure 2). A fluorodeoxyglucose positron emission tomography (FDG-PET) scan disclosed skull metastases. He was treated with phenoxybenzamine, amlodipine, and labetalol. Surgical resection of the pelvic mass was discussed, but the patient elected to defer surgery as the location of the primary tumor made it challenging to resect and would have required an ileal conduit.