Christopher L. Stout, Surgery Resident V, Department of Surgery, Mercer University School of Medicine, Medical Center of Central Georgia, Macon, GA; D. Benjamin Christie III, Surgery Resident IV, Department of Surgery, Mercer University School of Medicine, Medical Center of Central Georgia, Macon, GA; Keith Martin, Private Practice General Surgeon, Macon, GA
Christopher L. Stout, MD
Surgery Resident V
Department of Surgery
Mercer University School
Medical Center of Central
D. Benjamin Christie III, MD
Surgery Resident IV
Department of Surgery
Mercer University School
Medical Center of Central
Keith Martin, MD
Private Practice General
Introduction: Mature cystic teratomas of the pancreas are congenital abnormal growths that arise from totipotent cells and can differentiate into any tissue in the body, including cartilage, bone, hair, and teeth. These tumors are exceedingly rare and are usually diagnosed in children and young adults who present with abdominal or back pain, indigestion or obstructive symptoms, and a palpable mass.
Results and discussion: This paper describes an unusual case of a mature cystic teratoma of the pancreas in an older man who presented with back pain and no palpable mass. The diagnosis, radiology findings, and treatment of these lesions are discussed.
Conclusion: While unusual in older patients, the differential diagnosis of any cystic lesion of the pancreas should include mature teratoma, whether the lesion is found during a workup for abdominal or back pain or discovered during an exploratory laparotomy.
Mature cystic teratomas, also referred to as dermoid cysts, are benign extragonadal germ cell tumors with mature tissue derived from all three germinal layers. These lesions may contain differentiated tissue such as bone, teeth, hair, and cartilage. The gonads represent the most common site of occurrence, but cystic teratomas typically occur along the pathway of ectodermal cell migration, including the sacrococcygeal region, retroperitoneum, anterior mediastinum, and skull.1 The pancreas is a rare site of occurrence, and only 16 previous cases have been reported in the world literature since 1918.2-6 Although there are no reports of pancreatic teratomas becoming malignant, approximately 7% to 10% of other retroperitoneal teratomas are malignant.1
Mature cystic teratomas of the pancreas are usually found in children and young adults who present with abdominal or back pain, indigestion or symptoms of obstruction, and a palpable mass. We report an unusual case of a mature cystic teratoma of the pancreas in a 64-year-old man who presented with a history of back spasms and pain but no palpable mass.
A 64-year-old man underwent an extensive workup by his primary care physician due to a longstanding history of back spasms and pain. The patient's medical history was remarkable for hypertension controlled with medication, and his surgical history included a back operation but no abdominal operations. His social history was notable for heavy tobacco use, which he had ceased 10 years earlier, and consumption of a 12-pack of beer weekly. The patient's evaluation included a computed tomography (CT) scan of the abdomen, which showed a multiseptated, low-density mass with fat content in the body and tail of the pancreas bordered by the splenic vein (Figure 1). He was subsequently referred for surgical evaluation of the mass.
On physical examination, no abdominal masses were palpable. Laboratory evaluation, including a complete blood count, chemistry panel, liver function tests, and amylase and lipase levels, were all within normal limits. A CT-guided biopsy was obtained. Microscopically, the specimen predominantly consisted of squamous epithelium, and there were subepithelial lymphoid stroma without evidence of carcinoma or lymphoma. An endoscopic retrograde cholangiopancreatography (ERCP) was performed and confirmed no ductal involvement (Figure 2).
The patient consented to an exploratory laparotomy for excision of the tumor. A midline incision was made, and no gross pathology was observed upon entering the abdominal cavity. The lesser sac was entered and the stomach retracted superiorly, displaying the pancreas, which had a palpable, white-tan mass on its body and tail. There were very few collateral vessels extending from the splenic vein and artery. The pancreas was mobilized up to the neck and then transected, salvaging the spleen. A closed-suction drain was placed in the lesser sac. After a repeat exploration revealed no tumor in the retroperitoneum or abdomen, the incision was closed in the usual surgical fashion. The patient had an uneventful postoperative recovery, and he was discharged to home on postoperative day 5. At 2-year follow-up, the patient remained asymptomatic and had no signs of recurrence.
Pathologic evaluation of the mass revealed a 12 x 8 x 3.5-cm mature cystic teratoma of the pancreas that consisted of lobulated fatty tissue with focal areas of induration and a pinkish-red glistening cyst filled with a yellow pasty material (Figure 3). Microscopic examination with hematoxylin and eosin staining showed mature squamous epithelium with a pilosebaceous follicle, mature squamous epithelium with lymphoid stroma and adipose tissue, and mature squamous epithelium with subjacent lymphoid stroma and pancreatic tissue (Figure 4).
Mature cystic teratomas of the pancreas are rare benign lesions that are typically found in children or young adults.2 There is no male or female predilection.3 Patients often present with abdominal or back pain, indigestion or symptoms of obstruction, and a palpable mass. Our case was unusual because it occurred in an older man who had a longstanding history of back spasms and pain but no palpable mass.
It is important to differentiate mature cystic teratomas from the vast spectrum of benign and malignant tumors that comprise cystic lesions of the pancreas, because each lesion type is associated with different prognoses and management strategies. The differential diagnosis should include all cystic pancreatic lesions, including serous and mucinous cystadenomas, intraductal papillary mucinous neoplasms, pseudocysts, cystic islet cell tumors, and cystadenocarcinoma.2 Mucinous cystadenomas and intraductal papillary mucinous neoplasms undergo malignant degeneration and need to be excised, whereas serous cystadenomas are usually benign and can be observed. Mature cystic teratomas are different from solid teratomas of the pancreas, which are usually malignant.
Diagnosis and radiology findings
During the evaluation of a pancreatic teratoma, the radiologic appearance depends on the degree and type of differentiation of the tumor's germinal layers. The findings of fat-fluid levels, calcium, and fat on CT scanning are characteristic of these lesions and can aid in locating and diagnosing them.7 Endoscopic ultrasonography is also beneficial because it allows fine-needle aspiration of the cyst so that cytology and tumor markers can be obtained, of which carcinoembryonic antigen level is especially useful.8 Biopsy of any pancreatic cystic lesion must take into account the risk of seeding the peritoneum with tumor cells should a malignant neoplasm be present.9 Ultrasonography is highly accurate in differentiating malignant lesions from benign ones and can help clinicians determine the type of neoplasm that is present.10 ERCP helps delineate ductal origin or involvement and allows brushings for cytologic evaluations. If the lesion is found intraoperatively, sending a specimen for frozen section pathology can help diagnose mature teratoma.
Although mature cystic teratomas of the pancreas are not malignant, treatment is total excision because these lesions are true cysts that contain a secretory epithelium. External drainage of the teratoma, with or without marsupialization, results in growth of the tumor or a chronically draining fistula and should not be undertaken.4 Internal drainage has not been evaluated over the long-term. Because the differential diagnosis of pancreatic teratoma includes life-threatening or potentially malignant lesions, such as pancreatic pseudocysts and necrosis, cystic islet cell tumors, and cystadenocarcinoma, excision of these lesions is recommended. Solid teratomas of the pancreas also exhibit malignant potential and require excision.
Mature cystic teratomas usually occur in children or young adults and present as a palpable mass that causes abdominal or back pain, symptoms of gastrointestinal obstruction, or indigestion. Our report represents a deviation from the normal presentation of these lesions. Our patient was an older man whose only symptoms were back spasms and pain. Ultrasonography and CT scanning of the abdomen are helpful in delineating involvement and distinguishing cystic teratomas from other neoplasms and inflammatory diseases of the pancreas. The treatment is total surgical excision, because external drainage fails to treat the secretory epithelial layer of the tumor. Whether found during a workup for abdominal or back pain or discovered during an exploratory laparotomy, the differential diagnosis of a cystic lesion of the pancreas should include mature teratoma.
The authors have no relationship with any commercial entity that might represent a conflict of interest with the content of this article and attest that the data meet the requirements for informed consent and for the Institutional Review Boards.