A Diagnosis Dilemma: Pheochromocytoma Vs GIST In NF1

Presentation Number: MON-503
Date of Presentation: March 19, 2018, 2018

Farhana K. Polara, MD1, Julia Vargas-Jerez, MD1, Joe Lequerica, MD2, Tasneem Zahra, MD2.
1Lincoln Medical And Mental Health Center, Bronx, NY, USA, 2Lincoln Medical and Mental Health Center, New York, NY, USA.


Introduction- Neurofibromatosis Type 1 (NF1) can predispose to the development of neoplasms of eye, skin and nervous system. Less common tumors include those of neuroectodermal and mesenchymal origin like pheochromocytoma, carcinoid and gastrointestinal stromal tumors (GIST). Diagnosing and differentiating the different presentation of NF1 can be challenging as in our case. Case Report- 46-year-old-female non-smoker who had been diagnosed with NF1 10 years ago from skin biopsy in Dominican Republic presented with headaches, high blood pressure of 173/100mmhg and palpitations with heart rate of 126/min. She was not on any prescription medications and had only one similar presentation 10 years ago which needed hospitalization. She denied any surgical intervention, any drugs or toxin ingestion. None from her family had NF1 including her children. Denied any abdominal pain or lightheadedness. On exam she had numerous cutaneous neurofibromas, multiple café-au-lait macules and freckling. The patient was tested and found to have elevated levels of serum and urine metanephrines, normetanephrines and chromogranin A.She had normal TSH, calcitonin and cortisol level.She also had normal ECHO and no significant ectopy on holter monitoring. Initial MRI of the abdomen and pelvis done reported as a left upper quadrant lesion arising from small bowel with cystic component consistent with GIST. However, due to strong clinical suspicion of pheochromocytoma and positive metanephrines, the patient had a follow up CT abdomen with contrast which showed a heterogenous highly vascular mass arising from the lateral limb of the left adrenal with increased uptake on metaiodobenzylguanidine (MIBG) scan consistent with pheochromocytoma. Thyroid US was negative for any mass. The patient underwent successful surgical excision of her adrenal mass after 3 weeks therapy of phenoxybenzamine and 2 weeks of beta blocker. Subsequent to the surgery her symptoms resolved and had normal serum metanephrine levels.Discussion- Patients with NF1 can develop hypertension from multiple etiologies, including vasculopathy from neurofibrin deposition and intimal hyperplasia, renal artery stenosis or coarctation of aorta. Only in 0.1 to 5.7 percent of the patients, it is secondary to pheochromocytoma. However, recommendations are to check all patients with NF1 and hypertension for pheochromocytoma as was done in this case. Patients with NF1 can also have GIST that can presents with abdominal pain, bowel obstruction,gastrointestinal hemorrhage or totally asymptomatic. Pheochromocytoma has to be ruled out in these patients prior to surgical intervention. In rare cases of NF1 both GIST and pheochromocytoma can be present which portends a poor prognosis. Multiple imaging might be needed to differentiate between GIST and pheochromocytoma with confidence as in our case.


 F.K. Polara: None. J. Vargas-Jerez: None. J. Lequerica: None. T. Zahra: None.