Multicystic adenomatoid hamartoma of the pancreas: a hitherto undescribed pancreatic tumor occurring in a 3-year-old boy

Ductal hamartoma of the pancreas: A clinicopathologic study

BACKGROUND

Benign ductular proliferative lesions that resemble hepatic von-Meyenburg Complexes(VMC)/bile duct hamartomas have been noted to occur in the pancreas, but their incidence, clinicopathologic features and pathogenesis remains unknown. We present herein 3 patients that presented as cysts and call them pancreatic ductal hamartomas (PDH).

METHODS

Three cases of PDH were identified form a multi-institutional collaborative group, and their clinicopathological were reviewed. In addition, we also examined 115 consecutive pancreatic resections at our institutions for the presence of incidental PDHs.

RESULTS

The lesions were detected in each case during imaging for abdominal symptoms or grossing. The clinical suspicion was intra-ductal pancreatic mucinous cystic neoplasm (IPMN) in each case that led to pancreatectomy. The cyst fluid CEA was elevated in 2 of the patients tested. The patient age and gender were 73/M (case1), 68/F (case2) and 73/M (case3). In case1 besides the larger cystic lesion, numerous tiny lesions (0.1-0.3 cm) were seen throughout the pancreas. In case2 this was the only lesion, while in case3 there was another gastric-type IPMN with high-grade dysplasia. PDH were identified in 5(4.3%) of 115 consecutive pancreatectomy specimens. The PDHs measured 0.1-2.3 cm, and the histology is characterized by proliferation of irregular ductal structures lined by bland flattened to low columnar epithelium, variable cystic change and inspissated luminal secretions. The lining epithelium varied from non-mucinous pancreatico-biliary type to mucinous gastric foveolar-type, with occasional squamous metaplasia.

SUMMARY

PDH are seen in 4.5% of all pancreatectomy specimens and detected incidentally, but occasionally may become large and/or cystic enough leading to pancreatectomy. Their relationship to pancreatic carcinoma or IPMN remains currently unknown.

Pancreatic hamartoma: detection of harbouring NAB2-STAT6 fusion gene

AIM

Hamartomas in the pancreas are rare and are often histologically and morphologically similar to solitary fibrous tumours (SFTs). We examined the differences between hamartomas and SFTs at the molecular level.

METHODS AND RESULTS

Thirteen patients histopathologically diagnosed with pancreatic hamartoma were included in the study. We also performed STAT6 immunohistochemistry (IHC), which is used in the diagnosis of SFT. Furthermore, for the three cases in which RNA was extracted, reverse transcription polymerase chain reaction to search for NAB2-STAT6 fusions was used. Macroscopically, 13 patients had well-demarcated tumour lesions. Histologically, no islets of Langerhans were observed in the lesions, acinar tissue and ducts were unevenly distributed, and elastic fibres were not observed around the ducts by Elastica Van Gieson staining. One case contained a lipomatous hamartoma composed mainly of adipose tissue. Seven of the 13 cases demonstrated expression of STAT6 in the nuclei of intervening spindle cells. NAB2-STAT6 fusions were observed in two of the three cases in which RNA was extracted. These two cases also demonstrated STAT6 expression in spindle cells using STAT6 IHC. In one case of lipomatous hamartoma, we did not confirm NAB2-STAT6 fusion or STAT6 expression in STAT6 IHC.

CONCLUSION

Of the 13 patients histopathologically diagnosed with hamartoma, two demonstrated NAB2-STAT6 fusions, suggesting the existence of pancreatic hamartomas with molecular-level components identical to those of SFT.

Fetal Pancreatic Hamartoma Associated with Hepatoblastoma-An Unusual Tumor Association

Abdominal tumor masses are a very rare disease in the fetus. The authors present the first reported case of neonatal multicystic adenomatoid hamartoma of the pancreas associated with well-differentiated fetal epithelial subtype hepatoblastoma and reveal clinical, histologic, and imagistic aspects. Case presentation: A 36-week-old female newborn in whom a 25-week ultrasound showed a relatively homogeneous pancreatic echogenic mass (34 × 30 × 55 mm) with compression of the inferior vena cava and retrograde dilation. Postnatal CT showed a giant pancreatic tumor mass (113 × 70 × 60 mm), with areas enhancing contrast and cystic/necrotic areas and a hypodense, hypocaptive nodule of 8 × 6 mm located at segment IV of the liver; thrombosis of the subhepatic segment of the inferior vena cava and both renal veins. Histopathological and immunohistochemical studies confirmed the diagnosis of multicystic pancreatic adenomatoid hamartoma and well-differentiated fetal epithelial subtype hepatoblastoma. Conclusions: Pancreatic hamartoma can be difficult to diagnose (especially prenatal), with or without nonspecific symptoms. The synchronous presence of hepatoblastoma complicated the therapeutic conduct and prognosis of this case, with the diagnosis being confirmed histopathologically and immunohistochemically after liver biopsy.

A typical case of resected pancreatic hamartoma: a case report and literature review on imaging and pathology

Background

Pancreatic hamartomas are rare entities and difficult to diagnose before resection. We report a case of resected pancreatic hamartoma and literature review of typical characteristics of the lesion.

Case presentation

A 78-year-old man presented with a mass in his pancreas, which was incidentally identified when he experienced pneumonia. No remarkable symptoms were observed, and laboratory tests showed no abnormalities, except a slight carcinoembryonic antigen elevation. Enhanced computed tomography and magnetic resonance imaging showed a well-demarcated solid mass with heterogeneous contrast that was 2 cm in size. A gradual enhancement pattern was also observed. The biopsy revealed no specific findings; therefore, surgical resection was necessitated to confirm the diagnosis. Histopathologically, ducts, acinar cells, and adipose cells without atypia were observed among abundant fibrous stroma, but islets of Langerhans and peripheral nerves were absent. An immunohistochemical examination demonstrated CD34 and c-kit positive staining in the stromal cells, S-100 positivity in the adipose cells, and a lack of elastic fibers in the duct walls. The lesion was diagnosed as a pancreatic hamartoma.

Conclusion

Asymptomatic pancreatic hamartomas can avoid resection. A careful consideration of imaging and appropriate immunohistochemistry of biopsy specimen may facilitate accurate diagnosis before resection. Therefore, sufficient recognition of the characteristics of pancreatic hamartomas is desirable.

Pancreatic Lipomatous Hamartoma: A Hitherto Unrecognized Variant

Pancreatic masses consisting of lipomatous components clinically include lipoma, liposarcoma, lipomatous pseudohypertrophy of the pancreas, fat-containing neoplasms such as perivascular epithelioid cell tumor, and malignant neoplasm with lipoid degeneration. We present pancreatic lipomatous hamartoma, which has not been reported hitherto. A solid pancreatic mass was detected from a computed tomographic scan check-up in each of 3 cases of Japanese men. Macroscopically, well-demarcated solid lipomatous masses were detected at the uncus, body, and tail of the pancreas, respectively. Microscopically, the masses predominantly consisted of mature adipocytes with no atypia, but contained characteristics components of pancreatic hamartoma, such as small ducts, a well-preserved acinar structure, and/or fibrous stroma. On the basis of the unique features, lack of islets and absence of periductal elastic fibers, these tumors are a distinct variant of pancreatic hamartoma. Furthermore, high-mobility group AT-hook 2 expression in the fibro-adipocytes of this tumor indicated that these cells are an integral component of the pancreatic lipomatous hamartoma. Consequently, the unique tumors described herein are pancreatic lipomatous hamartoma, which must be discriminated from other lipomatous lesions of the pancreas.

Computed tomography and magnetic resonance imaging findings of pancreatic hamartoma: A case report and literature review

Pancreatic hamartoma is a rare benign malformation that resembles a neoplasm and may be mistaken for a malignancy. The imaging findings of pancreatic hamartoma are not well established, as only one radiological case report has been described since 1983. Herein, we discussed a case of pancreatic hamartoma in a 35-year-old woman and conducted a literature review focused on imaging findings and differential diagnosis of pancreatic hamartoma. Increased late enhancement on post-contrast dynamic study and absence of diffusion restriction may be characteristic MR imaging findings of pancreatic hamartoma that may narrow the differential diagnosis of hypervascular pancreatic lesions.

Pancreatic hamartoma in a premature Trisomy 18 female

Pancreatic hamartomas are extremely rare tumors in adults and even more so in children. They are lesions characterized by acinar, islet and ductal components found in varying proportions and in a disorganized pattern. We report a case of a premature female with trisomy 18 diagnosed by amniocentesis. The newborn was delivered by cesarean section at thirty-three weeks of gestation and expired within one hour of birth. Postmortem examination exhibited numerous features associated with Trisomy 18 including lanugo on the torso and arms, micrognathia, microstomia, left low-set ear with small flat pinna, closed ear canal, clenched fists with overlapping fingers, rocker-bottom feet, narrow pelvis, large right diaphragmatic hernia and left pulmonary hypoplasia. Microscopic examination of the pancreas revealed an area, 1.2 cm in greatest dimension, with branching ducts and cysts lined by cuboidal epithelium intermingled within primitive mesenchymal proliferation and exocrine glands. The cysts measured up to 0.2 cm and were surrounded by a collarette of proliferating spindle cells as highlighted by Masson's trichrome stain. A diagnosis of pancreatic hamartoma was rendered. A total of thirty-four cases of pancreatic hamartomas have been reported in the literature including twenty-seven in adults, five in children and two in newborns. Our case may be the third pancreatic hamartoma reported in association with Trisomy 18. We recommend that careful examination of the pancreas be performed in individuals with Trisomy 18 to further characterize this lesion as one of the possible abnormal findings associated with this syndrome.

A small pancreatic hamartoma with an obstruction of the main pancreatic duct and avid FDG uptake mimicking a malignant pancreatic tumor: a systematic case review

BACKGROUND

Pancreatic hamartomas are extremely rare and may be misdiagnosed as malignant tumors. We report herein a case of a small, solid-type pancreatic hamartoma.

CASE PRESENTATION

A 72-year-old female was incidentally detected pancreatic lesion by ultrasonography. Computed tomography and magnetic resonance imaging revealed a 2.0-cm solid lesion. The main pancreatic duct (MPD) was obstructed by the lesion in the head of the pancreas, and the upstream MPD was dilated. ¹⁸F-fluorodeoxyglucose (FDG) accumulated avidly in the lesion and increased in FDG intensity from the early to the delayed images. The histopathological studies confirmed the diagnosis of pancreatic hamartoma. Immunohistochemically, the cell membrane of the accessory glands and ducts showed homogeneous expression of glucose transporter type I and hexokinase II.

CONCLUSION

Pancreatic hamartomas causing dilatation of the MPD are extremely rare, and this appears to be the first case of a hamartoma to take up FDG avidly. It was a rare occurrence and should be noted that pancreatic hamartomas can cause an obstruction of the MPD and show avid FDG uptake, thereby mimicking malignant pancreatic tumors.

Pancreatic hamartoma, a rare benign disease of the pancreas: A case report

Pancreatic hamartoma is an extremely rare, non-neoplastic, mass-forming lesion that may be mistaken for malignancy, and the pre-operative diagnosis is particularly challenging. The published literature contains only 23 cases of pancreatic hamartoma. The majority of the cases reported patients with a single benign tumor-like disease that received a pancreatectomy. Immunohistochemical findings confirmed the diagnosis following surgery. The current study reports the case of a 53-year-old female who presented to the Department of Abdominal Surgery, Chinese Academy of Medical Sciences, Cancer Hospital (Beijing, China), due to abdominal pain. Abdominal magnetic resonance imaging revealed a 22×14-mm mass in the head of the pancreas. The patient was pre-operatively diagnosed with a pancreatic space-occupying lesion, and subsequently underwent a pancreaticoduodenectomy. The post-operative course was uneventful. Histological examination of the resected lesion resulted in a diagnosis of pancreatic hamartoma. There were no signs of recurrence at 55 months post-surgery.

Importance of NAB2-STAT6 Fusion in the Diagnosis of Pancreatic Solitary Fibrous Tumor with Hamartoma-Like Features: A Case Report and Review of the Literature

We report a case of pancreatic hamartoma-like solitary fibrous tumor which was differentiated from pancreatic hamartoma with the detection of NAB2-STAT6 fusion, a specific mutation for solitary fibrous tumors. A pancreatic well-demarcated solid nodule, 21 × 17 mm, of 82-year-old man was surgically enucleated. Microscopic findings were close to a pancreatic hamartoma that consisted of sparsely distributed pancreatic ducts and acini in heavily collagenized fibrous stroma. Neither islet nor peripheral nerve existed in the tumor. The fibroblastic cells in the stroma were immune-positive for CD34, CD99, and bcl-2. But these expressions were not decisive in the differentiation between solitary fibrous tumor and pancreatic hamartoma, because CD34 was positive for both tumors, and CD99 and bcl-2 expressions were not elucidated in the previous cases of pancreatic hamartomas. Thus, we evaluated NAB2-STAT6 fusion. The fibroblastic cells were positive for STAT6 and sequencing analysis revealed the gene fusion between NAB2 exon 4 and STAT6 exon 2, with which the final diagnos is of solitary fibrous tumor was achieved. In conclusion, detection of NAB2-STAT6 fusion has a great diagnostic value for pancreatic solitary fibrous tumors with hamartoma-like features.

Pancreatic hamartoma diagnosed after surgical resection

A pancreatic hamartoma is a rare benign lesion that may be mistaken for malignancy. A pancreatic hamartoma can present with vague, non-specific symptoms, which can be difficult to diagnose despite modern diagnostic tools. We report here a pancreatic hamartoma diagnosed after surgical resection. A 52-year-old female presented with postprandial abdominal discomfort. Abdominal computed tomography and pancreatic magnetic resonance imaging revealed a 2.2 × 2.5-cm cystic mass in the pancreatic head. The patient underwent a pylorus-preserving pancreaticoduodenectomy. The histopathological and immunohistochemical studies helped make the diagnosis of pancreatic hamartoma. Here, we report a case of pancreatic hamartoma and review the relevant medical literature.

Multicystic adenomatoid pancreatic hamartoma in a child: Case report and literature review

INTRODUCTION

Pancreatic tumor is a rare condition in children, but reasonably common in adults. Histopathology in children also differs from that in adults, with most cases being pancreatoblastoma, solid pseudopapillary tumor, or pancreatic endocrine tumors.

PRESENTATION OF CASE

A 14-month-old boy was noticed abdominal distension and referred to our hospital. Laboratory findings revealed leukocytosis and elevation of serum level of C-reactive protein and pancreatic enzymes. Radiological findings at admission were the huge abdominal cyst in abdominal computed tomography. As the levels of pancreatic enzyme elevated synchronous to oral feeding, total parenteral nutrition was needed. Besides radiographically the abdominal lesion changed from multiple large cystic type to multiple microcystic lesion including solid component over time. It was considered different diagnosis was pancreatic blastoma, pancreatic pseudo cyst, and lymphangioma and he was performed operation. The huge multicystic and partially solid tumor arising from the tail of pancreas existed from posterior of stomach to pelvic cavity. The tumor was completely resected without pancreatectomy and residual pancreas can be kept without tumor invasion. Histopathological finding was pancreatic hamartoma.

DISCUSSION

Pancreatic hamartoma was extremely rare, and only 17 cases were previously reported in the literature. This is the first case that the change of radiographic findings overtime was shown. We reviewed 17 cases (4 cases in children) of pancreatic hamartoma including our case.

CONCLUSION

Although extremely rare, pancreatic hamartoma should be considered in the differential diagnosis of cystic abdominal mass in children.

Multiple solid pancreatic hamartomas: A case report and review of the literature

Non-neoplastic tumor-like lesions in the pancreas are uncommon. Here, we present a case of multiple solid pancreatic hamartomas in a 78-year-old Japanese woman. Her computed tomography revealed a pancreatic mass, measuring 1.8 cm in maximum diameter. However, no symptoms were found. She was not an alcoholic and had no history of pancreatitis. The patient underwent a pancreatoduodenectomy, and three well-demarcated solid nodules measuring 1.7 cm, 0.4 cm, and 0.3 cm in diameter were found in the pancreatic head. Microscopically, the lesions were composed of non-neoplastic, disarranged acinar cells and ducts embedded in a sclerotic stroma with elongated spindle cells that lacked discrete islets. The stromal spindle cells were immunoreactive for CD34 and CD117. The histological diagnosis was multiple solid hamartomas of the pancreas. There has been no recurrence 30 mo after surgery. So far, 18 cases of pancreatic hamartoma have been reported in the English literature, including our case. Six out of these 18 cases seemed to fit the criteria of solid pancreatic hamartoma. Although the number of cases was limited, solid pancreatic hamartomas seem to be benign tumor-like lesions, which are found incidentally in healthy middle-aged adults, but occasionally involve the whole pancreas, resulting in a poor prognosis. Solid pancreatic hamartoma was sometimes associated with minor pancreatic abnormality, and multiple small lesions other than the main tumors were detected in a small number of cases. From these findings, one may speculate that solid pancreatic hamartoma could be the result of a malformation during the development of the pancreas.