[Exocrine meets neuroendocrine: mimickers of pancreatic neuroendocrine neoplasms]

Neuroendocrine neoplasms (NENs) originate from various epithelial or neuroectodermal tissues, can occur in any organ, including the pancreas, and are characterized by the expression of the neuroendocrine markers synaptophysin and chromogranin A. Pancreatic neuroendocrine tumors (PanNETs) are well-differentiated epithelial neoplasms with morphological and immunohistochemical features of neuroendocrine differentiation of low, intermediate, or high grade. Pancreatic neuroendocrine carcinomas (PanNECs) are clinically aggressive, high-grade (poorly differentiated) carcinomas with morphologic features suggesting neuroendocrine differentiation, a high proliferative rate (> 20 mitoses per 2 mm2 and Ki67 index > 20%), and immunohistochemical labeling for neuroendocrine markers. They include the small cell neuroendocrine carcinoma and the large cell neuroendocrine carcinoma categories.Neuroendocrine-like morphology coupled with immunohistochemical markers of neuroendocrine differentiation are highly specific. However, neuroendocrine markers may also be expressed in non-neuroendocrine neoplasms, which can therefore be confused with NENs. Mimickers of pancreatic NENs comprise a number of important pitfall tumors, including epithelial and non-epithelial neoplasms, such as acinar cell carcinomas, solid pseudopapillary neoplasms (SPNs), or even non-neoplastic lesions. All of these lesions have the expression of neuroendocrine markers in common, such as synaptophysin and chromogranin A, and although they are comparatively rare, they can cause considerable diagnostic problems. This review article deals with some of the most important mimickers of pancreatic neuroendocrine neoplasms and even non-neoplastic lesions, such as islet aggregation. The similarities and differences between these entities and pancreatic neuroendocrine neoplasms are highlighted, and key findings that facilitate the correct diagnosis are discussed.

Pancreatic PEComa, a not so uncommon neoplasm? Systematic review and therapeutic update

Pancreatic PEComas are extremely rare neoplasms with malignant potential, which mostly affect middle-aged women and are characterized by presenting melanocytic and myogenic markers in immunohistochemical analysis. There are no symptoms or pathognomonic imaging tests, so the diagnosis is established with the analysis of the surgical specimen or the FNA obtained with preoperative endoscopic ultrasound. The mean treatment consists on radical excision, adapting the intervention to the location of the tumor. To date, 34 cases have been described; however, more than 80% of them have been reported in the last decade, which suggests that it is a more frequent pathology than expected. A new case of pancreatic PEComa is reported and a systematic review of the literature is carried out according to the PRISMA guidelines with the aim of divulge this pathology, deepening its knowledge and updating its management.

Large cystic lymphangioma of the pancreas: unusual finding with differential diagnosis and therapeutic considerations

Lymphangiomas are rare benign tumours of lymphatic vascular origin. They are more common in the paediatric population and manifest mainly in the neck and axillary region. Retroperitoneal lymphangiomas are <1% and pancreatic origin is even rarer. We present a case of a pancreatic cystic lymphangioma in a 60-year-old woman with chronic diffuse symptoms, diagnosed because of newly onset of diabetes mellitus. She was successfully managed with distal pancreatectomy and spleenectomy en-bloc with the cystic mass without any complications. Cystic lymphangioma of the pancreas is a rare entity presenting with a challenging preoperative diagnosis as imaging modalities may provide ambiguous information. The clinician should be aware of its complicated differential diagnosis and its persistent and subtle symptomatology.

Extramedullary Plasmacytoma: A Rare Entity

Extramedullary plasmacytoma is an immunoproliferative disease of mature B cell that produces immunoglobulins by clonal expansion. Plasma cell neoplasms are responsible for less than 0.1% of all pancreatic masses, they can be primary or secondary to multiple myeloma (MM). We present the case of a 56-year-old man with extramedullary solitary plasmacytoma located in the pancreas, presented with abdominal pain and jaundice. Imaging characteristics are similar to those of other pancreatic diseases, and the diagnosis is confirmed by immunohistochemistry due to the presence of a homogeneous infiltrate of monoclonal plasma cells, which typically express CD38 and CD 138 markers and the presence of kappa/lambda light chains.

Pancreatic/peripancreatic neurogenic tumor; little known masses not to be missed

BACKGROUND

Retroperitoneal neurogenic tumors are extremely rare pathological entities; therefore, few clinical features and natural courses, especially originating from the pancreatic/peripancreatic regions, have been reported. This study aimed to investigate the clinicopathological features of pancreatic and peripancreatic neurogenic tumors and assess the diagnostic value of computed tomography (CT) and endoscopic ultrasound-guided fine needle biopsy (EUS-FNB).

METHODS

Between 2006 and 2018, patients who were diagnosed with neurogenic tumors were included. In total, 90 histologically confirmed cases of neurogenic tumors located in the pancreatic/peripancreatic regions were selected for analysis.

RESULTS

The mean age was 49.2 ± 13.1 years. There were no differences in sex distribution of the tumors. Schwannomas (44.4%) and paragangliomas (41.1%) were the most common neurogenic tumors. The sensitivity of CT was 62.2% in 90 cases. EUS-FNB was performed in 30 cases and the sensitivity of it was 83.3%. The diagnosis of neurogenic tumors with EUS-FNB or CT was not significantly associated with tumor location and size. Surgical resection was performed in 78 cases. Of the 12 patients who did not undergo surgery, 10 cases were followed-up without any increase in tumor size.

CONCLUSIONS

Through the present study, we verified radiological, pathological, and clinical aspects of the pancreatic/peripancreatic neurogenic tumors which little known before, therefore, this study can serve as the basis for research to present an optimal diagnosis and treatment of neurogenic tumors. In addition, EUS-FNB is useful in the diagnosis of pancreatic/peripancreatic neurogenic tumors with relatively high sensitivity and can help establish therapeutic plans before the surgery.

Robotic and standard surgical intervention as adjunct therapies for retroperitoneal ganglioneuroma resection: a case report

Background

Ganglioneuroma (GN) is ranked by the International Neuroblastoma Pathology Classification as a benign tumor. It can occur anywhere along the sympathetic nerve chain and surgical excision is the treatment of choice.

Case presentation

An 18-year-old female patient sought medical assistance after 6 months of constant dorsal and back pain radiating from the thoracic region to the right abdominal flank. Magnetic resonance imaging revealed a solid nodular lesion with heterogeneous post-contrast enhancement and lobulated contours, centered on the right foramina of D12–L1, with a projection to the intracanal space, which compressed and laterally displaced the dural sac and had a right paravertebral extension between the vertebral bodies of D11 and superior aspect of L2. Ganglioneuroma was diagnosed using immunohistochemical analysis. It was decided to use a surgical approach in two stages: robot assisted for the anterior/retroperitoneal mass and a posterior hemilaminectomy/microsurgical approach to attempt total resection, avoiding the traditional anterior thoracoabdominal surgical incision and optimizing the patient’s postoperative outcomes. No postoperative adverse events were noted, and the patient was discharged on postoperative day 5.

Conclusion

This retroperitoneal GN presentation was peculiar because it originated at the D12 nerve root, which extended to the retroperitoneal space and inside the spinal canal. We hope that our case report can assist future decisions in similar circumstances.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01146-x.

Pancreatic Schwannoma with Cystic Degeneration: A Case Report and Literature Review

Schwannomas originate from Schwann cells, and they are the most common benign neoplasms of the peripheral nerves. They can occur in most parts of the body but have a predilection for the head, the neck, and the flexor aspects of the extremities. Pancreatic schwannomas are uncommon, and only a few cases have been reported in the English literature. Approximately two-thirds of pancreatic schwannomas undergo cystic degeneration, and they should be considered in the differential diagnosis of solid pancreatic tumors with cystic changes to facilitate accurate diagnosis and optimal treatment. We report a case of a pathologically proven schwannoma in the pancreatic tail with multiple cystic and hemorrhagic changes followed by a review of relevant literature.

Imaging Features of Neurofibromatosis Type 1 in the Abdomen and Pelvis

OBJECTIVE. Loss of the neurofibromatosis type 1 (NF1) tumor suppressor protein causes uninhibited activation of the RAS oncogene, which leads to tumorigenesis in patients with NF1. This case-based review discusses imaging manifestations of NF1 in the abdomen and pelvis, highlighting key genetic associations and management to elucidate features different from the general population. CONCLUSION. The spectrum of pathologic findings includes gastrointestinal tumors such as gastrointestinal stromal tumors, genitourinary lesions including urogenital neurofibromas, vascular entities such as renal artery stenosis, and less common associations like lymphoma.

Comprehensive Review of Abdominopelvic Mesenchymal Tumors With Radiologic Pathologic Correlation and Update on Current Treatment Guidelines-Part 2

Soft-tissue sarcomas are a diverse group of rare mesenchymal malignancies accounting for only 1% of all solid adult malignancies. These have been categorized in 12 broad groups by the World Health Organization (WHO) with their recent update in 2013. Majority of them lack specific imaging features serving as imaging conundrums for a radiologist. These are often large masses at presentation as they are asymptomatic or cause vague clinical symptoms. These tumors are challenging for surgeons as well as they find it difficult to achieve complete resection because of complex intra-abdominal anatomy and their close relationship with critical structures. Often, a multidisciplinary approach is required to decide on the most appropriate management for these complex cases so as to provide optimal patient care. Knowledge of the WHO classification, pathologic features, and treatment options available helps the radiologist make a meaningful contribution in multidisciplinary discussions of such cases and overall patient care. Liposarcoma (well-differentiated and dedifferentiated liposarcomas), leiomyosarcoma, and gastrointestinal stromal tumor are the 3 most common primary intra-abdominal sarcomas. In part 1 of this article, general features of soft-tissue sarcomas and some of the common tumors from WHO category 1-4 found in abdomen and pelvis are discussed. Part 2 will focus on common tumors from remainder of the WHO categories.

18F-NaF Uptake in Retroperitoneal Neurofibroma and Uterine Leiomyoma Calcifications

A 48-year-old woman with intermittent lower back pain for 9 months and known retroperitoneal neurofibroma underwent F-NaF PET/CT scan to assess possible bony lesions causing the pain. Incidentally, the images showed elevated NaF activity in the retroperitoneal neurofibroma. In addition, uterine leiomyoma with heterogeneous calcifications revealed increased NaF activity.

Pancreatic Lymphangioma: A Case Report and Literature Review

We report a case of a 29-year-old woman with a pancreatic lymphangioma who presented clinically as a case of acute pancreatitis. Lymphangiomas are benign tumors of vascular origin with lymphatic differentiation, most commonly found in the head and neck. Pancreatic lymphangiomas are extremely rare, accounting for only 1% of abdominal lymphangiomas, with approximately 60 cases reported in the literature. Although imaging findings are characteristic and can point to the diagnosis, confirmation with fine needle aspiration and histopathologic correlation is necessary. Although these lesions are benign, they can often present a diagnostic dilemma and can be mistaken for other cystic pancreatic lesions, namely, pseudocysts, cysts, cystadenomas, and cystadenocarcinomas.

Nonepithelial Neoplasms of the Pancreas, Part 2: Malignant Tumors and Tumors of Uncertain Malignant Potential From the Radiologic Pathology Archives

Almost all neoplasms of the pancreas are derived from pancreatic epithelial components, including the most common pancreatic mass, primary pancreatic ductal adenocarcinoma (PDAC). Nonepithelial neoplasms comprise only 1%-2% of all pancreatic neoplasms. Although some may arise directly from intrapancreatic elements, many originate from mesenchymal, hematopoietic, or neural elements in the retroperitoneal peripancreatic space and grow into the pancreas. Once these tumors reach a certain size, it can be challenging to identify their origin. Because these manifest at imaging as intrapancreatic masses, awareness of the existence and characteristic features of these nonepithelial neoplasms is crucial for the practicing radiologist in differentiating these tumors from primary epithelial pancreatic tumors, an important distinction given the vastly different management and prognosis. In part 1 of this article, the authors reviewed benign nonepithelial neoplasms of the pancreas. This article focuses on malignant nonepithelial neoplasms and those of uncertain malignant potential that can be seen in the pancreas. The most common malignant or potentially malignant nonepithelial pancreatic tumors are of mesenchymal origin and include soft-tissue sarcomas, solitary fibrous tumor, and inflammatory myofibroblastic tumor. These tumors commonly manifest as large heterogeneous masses, often containing areas of necrosis and hemorrhage. The clinical features associated with these tumors and the imaging characteristics including enhancement patterns and the presence of fat or calcification help distinguish these tumors from PDAC. Hematopoietic tumors, including lymphoma and extramedullary plasmacytoma, can manifest as isolated pancreatic involvement or secondarily involve the pancreas as widespread disease. Hyperenhancing paragangliomas or hypervascular metastatic disease can mimic primary pancreatic neuroendocrine tumors or vascular anomalies.

Pancreatic desmoid tumor: A rare case with radiologic-pathologic correlation

A 39-year-old female patient was referred to our tertiary oncologic center for additional investigations relating to a suspect pancreatic tail lesion. An abdominal computed tomography scan and magnetic resonance imaging scan showed a solid lesion demonstrating progressive enhancement. Complete resection was obtained and the final diagnosis was that of a desmoid tumor of the pancreas, an exceptionally rare tumor demonstrating overlap with other solid and cystic lesions of the pancreas [1]. Therefore, it is important to recognize the essential role of pathology, particularly immunohistochemistry, in identifying this tumor. The high rate of postsurgical recurrence should prompt repeated follow-ups considering the potential aggressive nature of desmoid tumors.

Primary pancreatic perivascular epithelioid cell tumor (PEComa): A surgical enigma. A systematic review of the literature

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor, with distinctive morphology and expression of myo-melanocytic markers. Current scientific literature reported just 24 cases of pancreatic PEComas. With our systematic review, we aimed at improving our understanding of the disease, focusing on the knowledge gained on epidemiology, etiology, clinical presentation, diagnosis, treatment and prognosis.

METHODS

Based on the PRISMA guidelines, a systematic research was carried out on PubMed/MEDLINE, Web of Science, Scopus, EMBASE, and EBSCO using the search terms: ("perivascular epithelioid cell tumor" OR ″PEComa") and ("pancreas "OR″ pancreatic").

RESULTS

The 4th-6th decades of life and female sex (86.9%) turned out as the most affected. Pancreatic head was the most involved site (50%), with a single lesion in almost all cases. The diagnosis was only obtained after histopathological examination (70.8%). The clinical presentation was non-specific, abdominal pain being the main symptom (60.9%). At immunohistochemistry, PEComa showed benign epithelioid predominance and a strong positivity for HMB-45, Melan-A, and α-SMA. Surgical resection was performed in almost all cases, while for one patient the multidisciplinary group chose just endoscopic and imaging follow-up, based on the benign nature of the lesion.

CONCLUSIONS

The biological characteristics of pancreatic PEComa remain an enigma. Its prognosis seems to depend on whether atypical ("worrisome") histological features are available or not. Surgery turned out as the most appropriate treatment, without reaching any agreement on surgery timing. Further studies on larger population are needed to better understand the biological features of pancreatic PEComa, in order to set up guidelines in the diagnosis, treatment and follow-up.

Rare pancreatic tumors

In this review, we will focus on rare pancreatic tumors. Most of these tumors do not have distinct characteristic appearances so the key to diagnosis requires a combination of imaging appearance, laboratory data, patient demographics, and associated medical syndromes in order to narrow the differential diagnosis. Nonetheless, imaging plays a vital role in narrowing the differential and guiding management. While there are many variant pathologic entities that cannot be encompassed by a single review, we aim to illustrate the imaging appearance of less common pancreatic tumors highlighting key distinctive diagnostic characteristics and discuss the implications for management. While there is overlap in the imaging appearances of many of these entities, for educational purposes, lesions will be categorized into solid (hypoenhancing and hyperenhancing), cystic lesions, mesenchymal neoplasms, and neoplasms seen in younger patients (< 40 years).

Primary Leiomyosarcoma of the Pancreas-a Case Report and a Comprehensive Review

Purpose

Primary mesenchymal tumors of the pancreas are rare, with leiomyosarcomas the most encountered entities among the pancreatic sarcomas. With few exceptions, single case reports published over the last six decades constitute the entire scientific literature on this topic. Thus, evidence regarding clinical decision-making is scant.

Methods

Based on a case report and an extensive literature search in PubMed, we discuss the clinical aspects and current management of this rare malignancy.

Results

We identified only two papers with more than a single case presentation; these institutional patient series were limited to five and nine patients. Additionally, a few papers sought to summarize the individual case reports published in the English and/or Chinese language. The clinical presentation is rather non-specific. Moreover, modern imaging modalities are insufficiently accurate to diagnose leiomyosarcoma of the pancreas. Treatment goals include a complete resection with free margins. Proper morphologic examination using immunohistochemistry and the application of a grading system are clinically important for prognostication. The efficacy of adjuvant treatments has not been established.

Conclusion

Primary pancreatic leiomyosarcoma is extremely rare, and the scientific literature is primarily based on single case reports. Conclusions on management and prognosis should be drawn with caution. A multidisciplinary team consultation is warranted to discuss a thorough individual treatment plan based on the available scientific literature, despite its low evidence level.