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Abstract

Glomangiomas are benign growths of blood vessels, often found in the hands or fingers, and can cause pain, cold sensitivity, and tenderness. They can be associated with paraneoplastic hypoglycemia, a rare phenomenon where tumors produce substances that interfere with blood sugar regulation. IGF-2 exerts insulin-like activity and promotes hypoglycemia by binding to IGF receptors and insulin receptors. Patients with IGF-2-mediated hypoglycemia present with fasting hypoglycemia characterised by suppressed endogenous insulin, ketones, growth hormone, and IGF-1. Here, we report a rare case of glomangioma with inactivating mutations of PDGFRB and IGF1 presenting with hypoglycemia. A 28-year-old female came for evaluation of hypoglycemia episodes with elevated serum insulin and c-peptide. MRI of pancreas was unremarkable. Her symptoms began at the age of 14-15 years, and she was placed on metformin and acarbose, but discontinued due to poor tolerance. Her IGF-2 was elevated at 1122 ng/mL and neuroendocrine PET/CT showed a 7 mm right supraclavicular lymphadenopathy. A biopsy revealed round to ovoid epithelioid cells arranged around blood vessels. The tumor cells were strongly and diffusely positive for vimentin, SMA, focally positive for SMMS, and negative for desmin, h-caldesmon, S100, ER, PR, CD34, STAT6, beta-catenin, and negative for AE1/3, MNF-116, EMA, Cam5.2, CD34, synaptophysin, chromogranin, and INSM1. The Ki-67 proliferative index was <1%. Comprehensive genomic analysis showed a tumor mutation burden (inactivating PDGFRB variant noted) and low genomic complexity by copy number analysis. No reportable gene fusion was detected by RNA fusion panel. Taken together, a diagnosis of low-grade/benign pericytic neoplasm, compatible with glomangioma was rendered.