Endoscopic Ultrasound Elastography in Glucagonoma

Abstract

A 41-year-old Caucasian female presented with a painful blistering erythematous papular rash involving the lower extremities, perineum, buttocks and the perioral region and unintentional 60 lbs. weight loss over 6 months. Biopsy of the rash was suggestive of psoriasis. Even with appropriate treatment, her symptoms did not improve and she was evaluated for weight loss. Computed tomography revealed a 3 x 4 x 5 cm complex solid mass in the pancreatic region. Endoscopic Ultrasound (EUS) with fine needle aspiration (FNA) revealed a hypoechoic, homogenous mass involving distal body and tail of the pancreas. EUS Elastography (EUS-E) demonstrated a mixed green-blue hue (Elastography Score of 4-5) with a Strain Ratio of 12.24. FNA cytology showed groups of round to oval cells with moderate eosinophilic cytoplasm. Few cells had enlarged pleomorphic nuclei with prominent nucleoli. Mitotic figures were observed 3/20 high power fields (HPF). Pathology showed a large neuroendocrine tumor formed by islands and trabeculae of uniform tumor cells with large round nuclei prominent nucleoli. Foci of tumor necrosis were present and there were 5 mitotic figures per 50 HPF. Lymphovascular invasion with extensive parenchymal extension and osteoid formation was seen, there was no invasion into the splenic artery and all three lymph nodes in the specimen were benign. A diagnosis of well differentiated, stage T2N0Mx, grade 2 glucagonoma was made. Patient underwent curative resection and had complete resolution of the rash. EUS-E shows differences in tissue hardness based on their elasticity (Table 1). Strain Ratio (SR) is a semi-quantitative technique that gives the quotient of elasticities of two tissues. This has a higher diagnostic accuracy than EUS-E score alone as SR provides objective criteria and decreases inter-observer variability. The utility of EUS-E for characterization of pancreatic lesions has been proven in multiple recent studies and with the advent of better technology and analysis software, its use is fast gaining popularity EUS-E can be used as an adjunct to characterize suspicious pancreatic lesions. Differing patterns have been seen with pancreatic elastography and further studies are required to define a set characteristic pattern and form a correlation between strain ratio and elastography scoring.Table: Table. Endoscopic Ultrasound Elastography Scoring and CorrelationFigure: EUS Elastography (EUS-E) demonstrated a mixed green-blue hue (Elastography Score of 4-5) with a Strain Ratio of 12.24.