Endocrine Abstracts

Case history: This 33-year old Scottish female presented in February 2017 with a 3-month history of vomiting, erythematous vesicular pruritic rash and three stone weight loss. The rash started 1 day postpartum in January 2015 and migrated from dorsum of feet to both lower legs, upper thigh and torso. A negative biopsy for pemphigus led the team to suspect necrolytic migratory erythema (NME) in November 2016. Her past medical history includes gestational diabetes with her third pregnancy (January 2015).

Investigations: In February 2017, a CT chest, abdomen and pelvis revealed a 4.1 cm pancreatic tail mass and an extensive right pulmonary embolus. Endoscopic ultrasound showed brisk arterial phase uptake (Sonovue contrast), in keeping with a neuroendocrine tumour (NET). Fine needle aspirate of the pancreatic mass was consistent with glucagonoma. Plasma glucagon and chromogranin B levels were elevated (202 pmol/l (n< 50), 312 pmol/l (n<150) respectively). Vasoactive intestinal peptide, pancreatic polypeptide, gastrin, somatostatin, chromogranin A, plasma catecholamines, CA 19-9 and CEA were negative. Micronutrient screen, albumin and liver function tests were normal. Blood and capillary glucose remained within normal range since February 2017.

Results and treatment: Prior to her Octreotide scan, she received some symptomatic relief from subcutaneous octreotide infusion. As such, despite the negative Octreotide scan, subcutaneous octreotide injections were continued until her laparoscopic distal pancreatectomy in March 2017. This was complicated by a splenic infarction. In August 2017, she developed a pancreatic pseudocyst requiring pigtail stenting. Pathology showed an encapsulated Grade 1 well-differentiated NET with stage T3 N0 M0, R0. The pancreatic transection margin was free of tumour (Ki-67 proliferation index 3.4%). The tumour stained positive for CD 56, chromogranin and synaptophysin with variable positivity for glucagon. Postoperatively, her plasma glucagon (66 and 116 pmol/l) and chromogranin B remained elevated. This has since been managed with watchful observation.

Conclusions: Her case resembles most glucagonoma cases; with the delay in diagnosing NME, thromboembolism and severe weight loss. She meets two of the major criteria for glucagonoma; NME and pancreatic lesion. Unusually, she did not display any insulin resistance apart from gestational diabetes prior to development of NME. Despite the negative Octreotide scan, she had some symptomatic response to subcutaneous Octreotide prior to surgery. Some theories have suggested that Octreotide may stabilise glucagon levels, regardless of tumour octreotide uptake. Interestingly, her symptoms resolved completely following distal pancreatectomy, albeit the elevated post-operative glucagon level.