Carcinoma Ex Microcystic Adenoma of the Pancreas: A Report of a Novel Form of Malignancy in Serous Neoplasms

Intraductal papillary mucinous neoplasm of the pancreas presenting as a giant abdominal mass: A case report

Introduction

Intraductal papillary mucinous neoplasms (IPMNs) constitute a group of rare conditions with a potential for malignant degeneration. The appearance of symptoms should suggest degeneration. This case demonstrates an unusual case of a patient presenting an intestinal type IPMN that was revealed by a large abdominal mass.

Case report

47-year-old woman with a history of hydatid cyst of the liver. The patient was admitted to our hospital for management of large abdominal mass measuring 185 × 128*190 mm. Intra-operative findings showed a voluminous tumor, of approximately 20 cm in all its dimensions, with double solido-cystic component at the expense of the neck and the body of the pancreas. The patient underwent splenopancreatectomy. The histopathological examination confirmed the presence of intestinal type of IPMN of pancreas.

Discussion

Acute pancreatitis is revealed in the majority of cases of IPMNs, related to duct obstruction by secreting mucus plug. IPMNs are rarely the cause of a large abdominal mass. They are cystic lesions of slow evolution, macroscopically visible and rarely macrocystic, unlike serous cystadenoma. The tumor size is a powerful indicator of the malignancy of IPMNs. The current definitive and ideal treatment for main duct and mixed type IMPNs is a surgical resection.

Conclusion

IPMNs are a cystic lesion, rarely revealed by a large mass.

•

IPMNs are rarely the cause of a large abdominal mass.

•

The tumor size is a powerful indicator of the malignancy of IPMNs.

•

The current definitive and ideal treatment for main duct and mixed type IMPNs is surgical resection.

Nonmucinous Cystic Lesions of the Pancreas

CONTEXT.—

Pancreatic cystic lesions are increasingly diagnosed. Among other criteria, they are often distinguished in mucinous versus nonmucinous cysts. Mucinous pancreatic cystic lesions have received increasing attention, especially those known as precursors of pancreatic ductal adenocarcinoma. However, the group of nonmucinous cystic lesions of the pancreas includes numerous entities that may pose a diagnostic challenge. Their accurate diagnosis and classification are crucial for adequate patient management.

OBJECTIVE.—

To review the spectrum of nonmucinous cystic lesions of the pancreas, taking into consideration their epidemiology and typical clinical context, their characteristic gross morphology and histomorphology, as well as their immunohistochemical and molecular profile.

DATA SOURCES.—

Literature was searched and reviewed with MEDLINE via PubMed. Macroscopic and microscopic images were obtained from the archives of the Institute of Pathology, Heinrich Heine University and University Hospital of Duesseldorf, Germany.

CONCLUSIONS.—

Nonmucinous cysts of the pancreas comprise numerous, mostly rare entities displaying different biological behaviors. The most frequent are serous cystic neoplasms, solid-pseudopapillary neoplasms, cystic neuroendocrine tumors, and pancreatitis-associated pseudocysts. Accurate diagnosis can be achieved if characteristic clinical context, histomorphology, and immunoprofile are taken into account.

A case of a malignant serous neoplasm of the pancreas with synchronous vascular invasion and metachronous metastases

Serous neoplasms (SNs) of the pancreas are usually considered benign tumors. However, they rarely manifest malignant behaviors. Here we present a case of malignant SN and review the literature of malignant SN. A 71-year-old woman presented to our hospital with a palpable abdominal mass. Imaging studies revealed a 7 cm mass with a cluster of microcysts having a honeycomb appearance in the head of the pancreas, which invaded the superior mesenteric vein (SMV). After being clinically diagnosed with SN, pancreaticoduodenectomy was performed with resection of limited SMV. Microscopically, the tumor was diagnosed as an SN concomitant with the tumor thrombus in the SMV. Four years after the surgery, two liver tumors and two peritoneal nodules were detected and three of them were surgically resected. All of those lesions had a honeycomb appearance in their cut surfaces and they were microscopically indistinguishable from the originally resected SN. A review of the literature identified 22 cases of malignant metastatic SNs published to date. Even though extremely rare, metachronous metastasis could occur in SNs of the pancreas. Local invasion indicated an increased likelihood of future metastasis. Thus, periodic surveillance should be considered for SNs after resection, especially when they have a local invasion.

Metachronous Pancreatic Ductal Adenocarcinoma with Adjacent Serous Cystadenoma that Was Preoperatively Diagnosed by EUS-FNA: A Case Report and Review of the Literature

Pancreatic serous cystic neoplasms (SCNs), such as serous cystadenoma (SCA), are generally recognized as benign because malignant counterparts of SCNs have been extremely rare. In clinical practice, pancreatic cystic neoplasms diagnosed as SCNs have been managed by conservative observation, as long as the patients remained asymptomatic. We herein report a case of metachronous ductal adenocarcinoma that was discovered during long-term follow-up of SCN and review the related literature. To our knowledge, this was the first reported case of the local presence of ductal adenocarcinoma adjacent to SCA that was preoperatively diagnosed by endoscopic ultrasound-guided fine-needle aspiration.

Coexisting pancreatic serous cystadenoma and pancreatic ductal adenocarcinoma: A cytological-pathologic correlation with literature review

Pancreatic serous cystadenoma (SCA) is a benign neoplastic lesion with a distinctive gross and microscopic appearance consisting of numerous thin-walled cysts lined by uniform epithelial cells with clear cytoplasm and small nuclei. The vast majority of serous cystadenomas are benign. Pancreatic SCA has rarely been reported in association with other pancreatic lesions. We present a challenging case in which a cystic and solid pancreatic mass was identified on imaging studies. FNA was performed and showed clusters of atypical cells with significant nuclear pleomorphism (>4:1), disorganized, overlapping nuclei, and prominent nucleoli. The FNA diagnosis was positive for malignancy, consistent with adenocarcinoma. The patient underwent neoadjuvant therapy and pancreaticoduodenectomy. Final pathology showed a serous cystadenoma associated with small foci of high-grade PanIN. The lack of invasive adenocarcinoma in the resection specimen was most likely due to complete response of the tumor to neoadjuvant chemoradiation therapy, but it is also possible that only high-grade PanIN was present initially. To our knowledge, this is the first reported case of SCA and high grade PanIN/PDAC that was assessed by FNA. We discuss the cytologic differential diagnosis and how to avoid potential pitfalls highlighted by this case.

Benign Tumors and Tumorlike Lesions of the Pancreas

The pancreas is a complex organ that may give rise to large number of neoplasms and non-neoplastic lesions. This article focuses on benign neoplasms, such as serous neoplasms, and tumorlike (pseudotumoral) lesions that may be mistaken for neoplasm not only by clinicians and radiologists, but also by pathologists. The family of pancreatic pseudotumors, by a loosely defined conception of that term, includes a variety of lesions including heterotopia, hamartoma, and lipomatous pseudohypertrophy. Autoimmune pancreatitis and paraduodenal ("groove") pancreatitis may also lead to pseudotumor formation. Knowledge of these entities will help in making an accurate diagnosis.

Serous Microcystic Adenoma of Pancreas: A Case Series from a Tertiary Care Centre in Southern India

Serous microcystic adenoma is a rare exocrine tumour of the cystic neoplasm of pancreas seen predominantly in the elderly population. The first patient was a 56-year-old diabetic woman with abdominal pain, constipation and loss of weight since two months. The second patient was a 73-year-old female with complaints of abdominal pain and back pain since one year. The third patient was a 72-year-old diabetic man with complaints of burning sensation in the right lumbar region since two months. Clinical and laboratory examinations were normal. The radiological examinations of the first two patients showed multiloculated cystic lesion in the pancreas and of the third patient was suggestive of islet cell tumour. The histopathological examination of the three patients showed multiple cysts of varying sizes lined by cuboidal epithelium, showing no atypia. All the three patients were diagnosed as serous microcystic adenoma of pancreas. On follow up, all three patients had no recurrence. Serous epithelial neoplasms need to be differentiated from their non-neoplastic counterparts and other neoplastic lesions with cystic changes, in view of the differences in management. Serous microcystic adenomas have excellent prognosis.

Serous Neoplasms of the Pancreas: A Clinicopathologic Analysis of 193 Cases and Literature Review With New Insights on Macrocystic and Solid Variants and Critical Reappraisal of So-called "Serous Cystadenocarcinoma"

The literature on "variants" and "malignant" counterparts of pancreatic serous cystic neoplasms (SCNs) is highly conflicted. Clinicopathologic characteristics of 193 SCNs were investigated, along with a critical literature review. For the macrocystic (oligocystic) variant, in this largest series, a demographic profile in contrast to current literature was elucidated, with 21% frequency, predominance in female individuals (4:1), body/tail location (1.7×), younger age of patients (mean age, 50 y), and frequent radiologic misdiagnosis as other megacystic neoplasms. Solid SCNs were rare (n=4, 2%) and often misinterpreted radiologically as neuroendocrine tumors. Available fine-needle aspiration in 11 cases was diagnostic in only 1. Radiologic impression was "malignancy" in 5%. Associated secondary tumors were detected in 13% of resections, mostly neuroendocrine. Secondary "infiltration" (direct adhesion/penetration) of spleen, stomach, colon, and/or adjacent nodes was seen in 6 (3%) fairly large SCNs (mean, 11 cm) with no distant metastasis. Three SCNs recurred locally, but completeness of original resection could not be verified. Our only hepatic SCN lacked a concurrent pancreatic tumor. Literature appraisal revealed that there are virtually no deaths that are directly attributable to dissemination/malignant behavior of SCNs, and most cases reported as "malignant" in fact would no longer fulfill the more recent World Health Organization criteria but instead would represent either (1) local adhesion/persistence of tumor, (2) cases with no histologic verification of malignancy, or (3) liver SCNs with benevolent behavior (likely representing multifocality, rather than true metastasis, especially considering there was no fatality related to this and no reported metastases to other remote sites). In conclusion, in contrast to the literature, the clinicopathologic characteristics of solid and macrocystic SCN variants are similar to their microcystic counterpart, although their radiologic diagnosis is challenging. Recurrence/secondary invasion of neighboring organs occurs rarely in larger SCNs but seems innocuous. An SCN should not be classified as "malignant" unless there is clear-cut evidence of histologic malignancy or documented distant metastasis.

Synchronous resection of pancreatic serous cystadenocarcinoma and liver metastasis: First reported case and review of literature

Cystic neoplasms account for approximately 10-20% of all pancreatic cysts and 1% of pancreatic cancers. Serous cystadenomas are considered benign tumors with almost no malignant potential, and thus the management is typically only observation with serial imaging. According to the current World Health Organization classification, cases with distant metastases are defined as serous cystadenocarcinomas. To date, only 17 such cases with concomitant synchronous or metachronous liver metastasis have been described in the literature, and eight of these reports described treatment of secondary liver lesions. This report describes the first case of synchronous resection of pancreatic serous cystadenocarcinoma and liver metastasis in a 56-year-old female patient. The patient is currently well after 30 months of follow-up with no tumor recurrence or new metastatic liver nodules based on magnetic resonance imaging.

Serous cystic neoplasms of the pancreas: clinicopathologic and molecular characteristics

We herein summarize the pathology and most recent advances in the molecular genetics of serous cystic neoplasms of the pancreas. They typically present as relatively large, well-demarcated tumors (mean size, 6cm), predominantly occurring in females. Pre-operative diagnosis remains challenging; imaging findings and cyst fluid analysis often prove non-specific and fine-needle aspiration often does not yield diagnostic cells. Pathologically, they are characterized by a distinctive cytology referred to as "serous." Although they have ductal differentiation, they distinctly lack the mucin production that characterizes most other pancreatic ductal tumors, including ductal adenocarcinoma and its variants, intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). They instead produce abundant glycogen (glycogen-rich adenoma). Serous cystadenomas also lack the molecular alterations that characterize ductal neoplasms, such as mutation of KRAS (high prevalence in most mucinous ductal neoplasms), inactivation of SMAD4 (seen in ductal adenocarcinomas), and mutations in GNAS (seen in some IPMNs) and RNF43 (detected in MCNs and IPMNs). Instead, new molecular and immunohistochemical observations place serous pancreatic tumors closer to "clear cell neoplasms" seen in various other organs that are associated with the von Hippel-Lindau (VHL) pathway, such as clear cell renal cell carcinomas and capillary hemangioblastomas. Patients with VHL syndrome have an increased risk of developing serous pancreatic tumors and somatic mutations of the VHL gene are common in these tumors along with modification of its downstream effectors including hypoxia-inducible factor (HIF1), glucose uptake and transporter-1 (GLUT-1), a common factor in clear cell (glycogen-rich) tumors, as well as expression of vascular endothelial growth factor (VEGF), thought to be a factor in the striking capillarization of serous cystadenomas and other non-pancreatic clear cell tumors. VEGF may prove to be of significant diagnostic value since its elevation in cyst fluid has recently been found highly sensitive and specific for serous neoplasms. These molecular alterations establish serous tumors as prototypes of clear cell tumorigenesis and angiogenesis and may prove helpful both as diagnostic and non-surgical therapeutic targets.

Unique presentation of giant metastatic microcystic serous adenocarcinoma of the pancreas

Tumors of the pancreas that contain substantial cystic components include mainly mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, solid pseudopapillary tumor, and cystadenomas (which encompass microcystic, macrocystic/oligocystic, and rare solid serous adenomas). Microcystic adenoma of the pancreas is a tumor that is benign in nature. Malignant transformation in the tumor with metastases is rare and only about 26 cases have been reported so far. Here we present a giant microcystic adenoma of the pancreas, possibly the largest ever malignant type in this group ever reported in the literature with extensive metastases to the liver and causing extensive compression and encasement on surrounding structures.