SELECTIVE ACTH SAMPLING IN LOCALIZING SOURCE OF ACTH IN VON HIPPEL LINDAU DISEASE WITH PANCREATIC NEUROENDOCRINE TOMOUR AND RENAL CELL CARCINOMA

Abstract

INTRODUCTION
Crushing’s sundrome (CS) in a patient with VHL has been attributed to a number of possible causes; pancreatic NET and renal cell carcinoma. The precise location of ectopic ACTH aid enormously in the management of VHL.

CASE
A 31-year-old woman with Type 2 diabetes and family history of VHL presented with florid features of CS in her second trimester of pregnancy. Investigations supported a diagnosis of ACTH dependent CS. She underwent emergency caesarean section due to preeclampsia at 28 weeks gestation. MRI pituitary was normal. CT abdomen showed an enlarged pancreas, almost completely cystic and a right renal mass (3.7x2.7x4 cm). Serum chromogranin A was elevated. Twenty-four hour urinary free metanephrine was normal. Selective ACTH sampling was done with bilateral IPSS to elicit source of ACTH. Increased gradient of ACTH level compared to the periphery was detected from the hepatic vein that drains the pancreas (hepatic vein:138.92 pg/mL, IVC:115.12 pg/mL, renal vein:100.2 pg/mL). Total pancreatectomy and right nephrectomy were performed. A week after surgery, am cortisol was 103 nmol/L. HPE identified a solid tumour (16X12X12X mm) at the pancreatic tail which stained positive to Chromogranin A, synaptophysin and ACTH with mitoses of 0-1/10hof and a Ki67 index of 2%. The renal mass was a Grade 1 clear cell renal cell carcinoma. Two months later, there was resolution of cushingoid features.

CONCLUSION
When managing VHL with CS, there is always a possibility of more than one source of ACTH production. The use of selective ACTH sampling may be considered where functional imaging (DOTATATE) is unavailable to delineate the cause.