Endocrine Abstracts

Pheochromocytoma (PCC) is a rare tumor that arises from the adrenal medulla, usually presents with headache, sweating and palpitations due to excessive catecholamine release. However, PCC may secrete neuropeptides, hormones and cytokines, such as interleukin-6 (IL-6)) resulting in unusual clinical manifestations. A 48-year-old woman with a previous history of type 1 neurofibromatosis (NF1) and hypertension was referred to discarded PCC. Laboratory tests revealed leukocytosis and thrombocytosis with increased erythrosedimentation rate (ESR) and elevated urinary metanephrine (table 1). Abdominal CT revealed a left bilobed adrenal tumor 33 × 32 mm in the largest dimension (40 HU). Oncohematological and myelodysplastic disease were discarded (mutation JAK2- V617F, trasloc 9-22 and bcr-abl were negative). She had no fever but cytokines secretion was suspected and IL-6 was elevated (table1). Uneventful laparoscopic adrenal surgery was performed. After surgery all biochemical parameters were within the reference range and blood pressure normalization was achieved.

Discussion

It has been previously described that PCC may secrete cytokines with systemic inflammatory response syndrome (SIRS). IL-6 is a multifunctional molecule that plays an important role in hematopoiesis and immune and inflammatory responses. IL-6 over-production can be either ascribed directly to the tumor or indirectly accounted for tumoral production as a consequence of the high levels of circulating catecholamines. Symptoms relief, inflammatory marker and hematologic parameters normalization following the decrease in IL-6 level after tumor resection strongly supports the role of IL- 6 in the unusual presentation of our case. Our patient had mild hypertension despite high catecholamine levels and could be explained by the increased nitric oxide synthesis due to IL–6 activity, which might have led to vasodilation.

Conclusion

PCC may be a cause of paraneoplastic syndrome with marked increase in the levels of inflammatory markers. IL-6 appears to be the primary mediator. PCC has to be considered in the vast differential diagnosis of oncohematological and myelodysplastic syndromes when common causes are ruled out.