Magnetic Resonance Imaging Findings of Intrapancreatic Accessory Spleen

A 15-year-old girl was referred for facial hirsutism and obesity. She had been seen five years ago for premature pubarche and otherwise had no previous medical or surgical history. Other physical examination findings were normal. Laboratory tests showed elevation of serum free testosterone and D4-androstenedione. Transabdominal ultrasonography (US) revealed a bilateral excessive ovarian size, numerous small peripheral follicles and increased central stroma, suggesting the diagnosis of polycystic ovary syndrome. However, US also demonstrated a 2.5 x 2.3 cm pancreatic tail mass (asterisk, Figure 1A). Magnetic resonance imaging (MRI) was performed subsequently and confirmed the presence of a mass of the dorsal surface of the pancreatic tail. The mass was mildly hypointense on T1-weighted imaging, and hyperintense on T2-weighted imaging compared to the surrounding pancreas, but was isointense to the spleen on all unenhanced sequences, including Diffusion-weighted imaging (DWI) sequences (with b-values of 50 and 800 sec/mm2, Figures 1B and 1C, respectively). It showed however a slightly distinctive enhancement pattern to the spleen on dynamic contrastenhanced MRI (i.e. slightly hypointense imaging of the spleen on early and late arterial phases and isointense on venous phase) (Figures 1D, 1E and 1F, respectively).