Deteriorating diabetes and an atypical Rash: Unmasking a glucagonoma — ASN Events
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Deteriorating diabetes and an atypical Rash: Unmasking a glucagonoma (#410)

Braden Engelbogen 1 , Jimmy Shen 1 2 , Jennifer Wong 1 3
  1. Department of Endocrinology, Monash Health, Clayton, Victoria, Australia
  2. Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, Clayton, Victoria, Australia
  3. School of Clinical Sciences, Monash University, Clayton, Victoria, Australia

Glucagonoma is a rare functioning pancreatic neuroendocrine tumour (pNET) arising from pancreatic alpha cells, accounting for <5% of pNETs (1,2). Glucagonoma syndrome comprises necrolytic migratory erythema (NME), type 2 diabetes mellitus (DM), weight loss, or glossitis along with an elevated glucagon level (3,4). 

A 74-year-old man was referred by the dermatology service with a two-month history of an erosive buttock rash suspicious for NME in addition to deterioration in diet-controlled DM (HbA1c 6.6% to 8.5%) with no associated weight loss. Skin biopsy was non-diagnostic and demonstrated non-specific psoriasiform dermatitis without the vacuolated keratinocytes characteristic of NME. Fasting glucagon, vasoactive intestinal peptide and pancreatic polypeptide was elevated at >522 pg/mL, 283.0 pmol/L and 112.4 pmol/L (reference range ≤208 pg/mL, 7.3-25.4 pmol/L, 0.0-100.0 pmol/L). MRI identified an indeterminate 8×16 mm T2-hyperintense lesion in the pancreatic tail, and subsequent 68Ga-DOTATATE PET confirmed intense tracer uptake (SUVmax 20.8) without metastatic disease. Histology from surgical resection confirmed a 12 mm grade 1 pNET (Ki67 <3%), with immunohistochemistry and post-operative glucagon levels pending. The rash resolved rapidly following resection.

Glucagonoma syndrome reflects the systemic catabolic effects of chronic hyperglucagonaemia. Diagnostic criteria are not formally established; NME is considered near-pathognomonic of the syndrome (5). The 2023 ENETS guidance suggests that glucagon levels above 500 pg/mL support the diagnosis (5). At diagnosis tumour size is typically large, and metastatic disease is commonly present, in contrast to this case (6). Surgical resection is first-line therapy for non-metastatic disease and aids symptom control in metastatic disease; somatostatin analogues are the first-line medical therapy where surgery is not pursued, or can serve as adjunctive therapy (3-5).

Glucagonoma should be considered in patients with deterioration in diabetes and an atypical dermatosis. The diagnosis is supported by markedly elevated glucagon levels and 68Ga-DOTATATE avidity. Surgical resection remains the first-line, and potentially curative, treatment.

  1. Albers MB, Sevcik M, Wiese D, Manoharan J, Rinke A, Jesinghaus M, et al. Characteristics, therapy, and outcome of rare functioning pancreatic neuroendocrine neoplasms. Sci Rep. 2024;14(1):18507. doi:10.1038/s41598-024-68290-1.
  2. Qu Y, Li H, Wang X, Chen Y, Guo Q, Pei Y, et al. Clinical characteristics and management of functional pancreatic neuroendocrine neoplasms: a single institution 20-year experience with 286 patients. Int J Endocrinol. 2020;2020:1030518. doi:10.1155/2020/1030518.
  3. Armeni E, Branton A, Porto J, Mandair D, Hayes AR, et al. Diagnostic characteristics, treatment outcomes, and prognostic factors in glucagonomas. Endocr Oncol. 2025;5(1):e240083. doi:10.1530/EO-24-0083.
  4. Perrier M, Brugel M, Gérard L, Goichot B, Lièvre A, Lepage C, et al. Characteristics and treatment options of glucagonomas: a national study from the French Group of Endocrine Tumors and ENDOCAN-RENATEN network. Eur J Endocrinol. 2023;189(6):575-583. doi:10.1093/ejendo/lvad157.
  5. Hofland J, Falconi M, Christ E, Castaño JP, Faggiano A, Lamarca A, et al. European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes. J Neuroendocrinol. 2023;35(8):e13318. doi:10.1111/jne.13318.
  6. Anelli S, Mazzilli R, Zamponi V, Giorgini B, Golisano B, Mancini C, et al. Glucagonoma and glucagonoma syndrome: an updated review. Clin Endocrinol (Oxf). 2025;103(4):417-426. doi:10.1111/cen.15300.