Malignant Pheochromocytoma Presenting as a Large Adrenal Mass With Cavoatrial Tumor Thrombus

A 50-year-old female with newly-diagnosed bilateral breast cancer presented with a large right adrenal mass and tumor thrombus in the inferior vena cava extending into the right atrium. A few days before presentation, abdominal ultrasound for evaluating abdominal pain had found a 9-cm right adrenal mass. Breast cancer metastasis was suspected. FDG-PET/CT confirmed the large right adrenal mass which exhibited intense FDG uptake with maximal standard uptake value (SUVmax) of 33.6 and high non-contrast Hounsfield units (>40) (Figure 1, red arrows). Furthermore, FDG-PET/CT revealed a tumor thrombus in the inferior vena cava extending into the right atrium (Figure 1, yellow and blue arrows). A left breast lesion was also noted with SUVmax of 5 (Figure 1, green arrow). No other FDG-avid lesions were found. MRI demonstrated a heterogeneously enhancing right adrenal mass with intra-tumoral cystic degeneration and a contiguous tumor thrombus growing into the right atrium through the inferior vena cava (Figure 1). The patient denied history of hypertension but recalled recent episodes of "panic attack" characterized by palpitations and feelings of dread. She also complained of recent fatigue, abdominal pain, and weight loss of 10 lbs. She denied hirsutism. Her family history was positive for breast cancer and colon cancer but negative for endocrine tumors. Physical examination results were unremarkable. Plasma normetanephrine was 10.71 nmol/L (normal <0.89) and metanephrine <0.1 nmol/L (<0.49). What is the diagnosis? Answer: Malignant pheochromocytoma with cavoatrial tumor thrombus. Pheochromocytoma is frequently encountered in patients with suspected adrenal metastasis but there are no clear clinical predictors of pheochromocytoma in such patients.1Yu R. Nissen N.N. Dhall D. Wei M. Pheochromocytoma in patients suspected of harboring adrenal metastasis: management and clinical predictors.Endocr Pract. 2008; 14: 967-972https://doi.org/10.4158/EP.14.8.967Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Consideration of pheochromocytoma in the differential diagnosis is thus key to the correct diagnosis of adrenal mass. Malignant pheochromocytoma characterized by tumor thrombus is very rare and poses surgical challenges due to vascular involvement.2Hamidi O. Young Jr., W.F. Iñiguez-Ariza N.M. et al.Malignant pheochromocytoma and paraganglioma: 272 patients over 55 years.J Clin Endocrinol Metab. 2017; 102: 3296-3305https://doi.org/10.1210/jc.2017-00992Crossref PubMed Scopus (189) Google Scholar,3Hartgrink H.H. Roelfsema F. Tollenaar R.A. Hiddema P.A. Pijl M.E. van de Velde C.J. Primary pheochromocytoma extending into the right atrium: report of a case and review of the literature.Eur J Surg Oncol. 2001; 27: 115-119https://doi.org/10.1053/ejso.2000.1020Abstract Full Text PDF PubMed Scopus (17) Google Scholar After alpha and beta blockage, the patient underwent open en bloc resection of the pheochromocytoma (9.2-cm) and tumor thrombus under cardiopulmonary bypass with circulatory arrest (Figure 2). Histological examination confirmed pheochromocytoma with high PASS (Pheochromocytoma of the Adrenal gland Scaled Score) of 12 (a score≥4 is consistent with malignant behavior). The patient recovered well postoperatively and underwent bilateral mastectomy a few months later. Genetic test of a panel of 88 genes associated with hereditary tumors showed heterozygous variants of unclear significance in FH (a pheochromocytoma susceptibility gene) and RECQL (a breast cancer susceptibility gene). She had no evidence of recurrence or metastasis 1 year after the pheochromocytoma resection. This case highlights that pheochromocytoma and even malignant pheochromocytoma can be encountered in patients with suspected adrenal metastasis and biochemical tests for pheochromocytoma should be performed in those patients. The authors have no multiplicity of interest to disclose. ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: