Rare case of pancreatic dermoid cyst

Clinical History

46-year-old female patient presented to gastroenterology OPD with vague epigastric pain and discomfort for one month. There was no history of vomiting, jaundice, anorexia or weight loss. On physical examination, there was mild tenderness in the epigastric region. Laboratory investigations did not reveal any abnormality. Ultrasonography and Computed Tomography were performed.

Imaging Findings

Ultrasonography revealed a large well-defined predominantly hyperechoic mass lesion in head and uncinate process of pancreas without any internal vascularity (Fig. 1). Dynamic contrast-enhanced CT of abdomen revealed a well-defined cystic lesion in the head and uncinate process of pancreas measuring approximately 8.6 x 8.4 x 9.2 cm. The lesion showed a mildly thickened wall with few foci of calcification and intralesional fat fluid level and dermoid plug (Fig. 2). The mass was causing indentation on the main portal vein and splenoportal confluence antero-superiorly, superior mesenteric artery and superior mesenteric vein medially and anterior surface of the IVC posteriorly without any attenuation of the vessels (Fig. 3, 4, 5). The mass was compressing the common bile duct and main pancreatic duct with upstream bilobar intrahepatic biliary radical and distal MPD dilatation (Fig. 6, 7). The rest of the pancreas appeared normal in size, shape and contrast enhancement. No surrounding inflammation or lymphadenopathy were seen.

Discussion

Dermoid (teratoma) are tumours derived from all the three germ layers, namely ectoderm, endoderm and mesoderm. They usually occur along the midline from cranium, mediastinum, retroperitoneum to the sacrococcygeal regions [1]. They are most commonly seen in the ovaries. Pancreas is an unusual location for dermoid cyst [2, 3]. Most of the pancreatic dermoids occur in head and body regions [4]. Most patients are usually asymptomatic or present with non-specific complaints like nausea, vomiting, abdominal pain, fatigue and anorexia [3, 4]. Biochemical markers like CA 19-9 and CEA used for diagnosis of cystic pancreatic neoplasms are usually not elevated in patients with dermoid.

Characteristic radiological appearance of a dermoid is that of a mass with fat, fat fluid level, dermoid plug and calcific foci. On ultrasonography, they appear as well-defined hyperechoic masses with calcific foci causing acoustic shadowing [4]. On contrast-enhanced Computed Tomography, they appear as well-defined, fat-containing lesions with fat fluid level and calcification in their walls [4]. On Magnetic Resonance imaging, fat appears as hyperintense on T1 weighted images and is suppressed on fat saturated images. On T2 weighted images, the fluid component appears bright. Recently, endoscopic ultrasonography is being used for sampling of the cyst wall and/or aspiration of its contents for cytological and biochemical analysis.

Although rare, malignant change is seen in 7-10 % of retroperitoneal teratomas [5], therofore histopathological evaluation of the entire cyst wall is essential to rule out the presence of any immature foci.

Surgical excision is considered standard therapy in symptomatic patients and those with risk of malignancy (elderly, size > 2-3 cm) [6]. In our case, surgical excision was not done as the lesion was in close relation to major abdominal vessels, namely portal vein, superior mesenteric artery, superior mesenteric vein and IVC. The patient was counselled about the symptoms that might occur due to mass effect of the lesion like jaundice, gastric outlet obstruction and/or bowel obstruction and was asked to report to emergency in case of any symptoms.

Any cystic pancreatic lesion with fat, fat fluid level, dermoid plug and calcific foci should be considered as cystic pancreatic teratoma. Lack of these characteristic features on imaging may pose difficulty in preoperative diagnosis and may require surgical excision.

Differential Diagnosis List

Final Diagnosis

Pancreatic dermoid cyst

URL:	https://www.eurorad.org/case/13936
DOI:	10.1594/EURORAD/CASE.13936
ISSN:	1563-4086