MON-527 - Malignant Triton Tumor Masquerading as an Adrenal Mass

Background: Neurofibromatosis is associated with a variety of neoplasms, including pheochromocytoma and malignant peripheral nerve sheath tumors.

A 33-year old gentleman with a history of neurofibromatosis type I (c.4577+1G>T) presented for several months of increasing abdominal pain radiating to his back, an unintentional 30 lb. weight loss, and early satiety. His exam was notable for multiple small neurofibromas, diffuse cafe-au-lait spots, and a large, non-tender LUQ mass. CT imaging was obtained and revealed a 13.5 cm x 16 cm heterogeneously-enhancing soft tissue mass in the left upper quadrant, and the left adrenal gland was not visualized, raising suspicion for possible adrenal origin. Multiple mildly complex hypodense intramuscular and subcutaneous soft tissue lesions were also seen within the abdomen and pelvis, raising concern for extensive soft tissue metastatic lesions. Given concern for primary adrenal pathology as well as increased risk of pheochromocytoma with NF1, biochemical work-up was undertaken pre-operatively. DHEA-S was noted to be 214 ug/dL (138.5 - 475.2 ug/dL), LDDST cortisol of 8.7 ug/dL ( < 1.8 ug/dL) with dexamethasone level of 328 ng/dL (post LDDST reference 140 - 295 ng/dL) and ACTH of 10.8 pg/mL (7.2 - 63.3 pg/mL), normetanephrine 77.3 pg/mL (0.0 - 210.1 pg/mL), metanephrine 30.6 pg/mL (0.0 - 88.0 pg/mL), aldosterone < 1.00 ng/dL (0.0 - 30.0 ng/dL) and renin of 1.547 (0.167 - 5.380 ng/mL/hr). Twenty-four hour urine metanephrine testing was also performed and was within normal limits. Surgical resection of the mass was recommended. He was started on stress dose steroids peri-operatively given concern for pre-operative cortisol excess. Intra-operatively, the patient was found to have a 20 centimeter left adrenal mass that was densely adherent to surrounding structures including the renal hilum, renal vein, and the left kidney, which was deemed not salvageable due to its intimate association with the tumor capsule and its vasculature. Pathology revealed a 19 cm high grade malignant peripheral nerve sheath tumor with rhabdoid and focal chondroid differentiation (malignant triton tumor) within or adjacent to the adrenal gland, which was excised with overlying adrenal and fibroconnective tissue. Post-operatively, hydrocortisone was progressively tapered down. The patient was seen by medical and radiation oncology and treatment with doxorubicin/ifosfamide was initiated; given the presence of a high grade sarcoma and invasion into local structures, radiation was not recommended.



Conclusion: Adrenal tumors can be associated with various genetic syndromes. Triton tumor is an extremely rare and aggressive variant of malignant peripheral nerve sheath tumors with rhabdomyosarcomatous differentiation. Although NF1 is associated with an increased risk of pheochromocytoma, when evaluating adrenal tumors, it is important to employ a wide differential diagnosis.

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