Adenosquamous carcinoma of pancreas: CT and MR imaging features in eight patients, with pathologic correlations and comparison with adenocarcinoma of pancreas

Successful pancreatectomy after conversion-intended chemotherapy using gemcitabine and nab-paclitaxel for unresectable adenosquamous carcinoma of the pancreas: a case report

BACKGROUND

Adenosquamous carcinoma of the pancreas (ASCP) accounts for only 1-4% of all pancreatic exocrine cancers and has a particularly poor prognosis. The efficacy of chemotherapy for ASCP remains unknown because of the small number of cases, and few studies have evaluated conversion-intended chemotherapy.

CASE PRESENTATION

A 76-year-old woman was referred to our hospital because of epigastric pain and nausea. A preoperative contrast-enhanced multidetector row computed tomography (MDCT) scan revealed a 17 × 17 mm low-density tumor with an ill-defined margin at the arterial phase in the pancreatic head. The tumor involved the common hepatic artery, left hepatic artery bifurcated from the common hepatic artery, and gastroduodenal artery, and was in contact with the portal vein. Fluorodeoxyglucose-positron emission tomography (FDG-PET) showed an uptake in the pancreatic head but no evidence of distant metastasis. The tumor was diagnosed as an adenocarcinoma of the pancreatic head and staged unresectable because the common and left hepatic arteries were involved. Hence, the patient underwent seven courses of conversion-intended chemotherapy using gemcitabine and nab-paclitaxel for pancreatic ductal adenocarcinoma over 7 months. After chemotherapy, the tumor shrank to 10 × 10 mm on contrast-enhanced MDCT. Consequently, the boundary between the tumor and major vessels of the common and left hepatic arteries and the portal vein became clear, and the involvement of the arteries with the tumor was evaluated to be released. The contact of the tumor to the portal vein also reduced to less than half the circumference of the portal vein. FDG-PET showed decreased accumulation in the tumor. Hence, the tumor was judged resectable, and pancreaticoduodenectomy was performed. The tumor and major blood vessels were easily dissected and R0 resection was achieved. The patient experienced no major complications and was discharged on postoperative day 28. The tumor was revealed as ASCP via pathological examination. The patient is alive and recurrence-free seven months after surgery. This is the first report of successful R0 resection for an initially unresectable ASCP following conversion-intended chemotherapy using gemcitabine and nab-paclitaxel regimen.

CONCLUSIONS

Conversion-intended chemotherapy using gemcitabine and nab-paclitaxel regimen may be effective for ASCP.

Pancreatic Adenosquamous Carcinoma Presenting as a Gastric Lesion

Pancreatic adenosquamous carcinoma, an uncommon subtype of pancreatic adenocarcinoma, is characterized by an aggressive course and poor prognosis, with the only method of cure being surgical resection at the time of diagnosis. It is a complex condition, as it presents nonspecifically and remains indistinguishable from pancreatic adenocarcinoma without imaging techniques despite its aggressive nature. We report an atypical case of pancreatic adenosquamous carcinoma, presenting with marked anemia, found on endoscopy to have a gastric mass. This is of interest to readers as a reminder that pancreatic cancers may present with gastric invasion and should remain on the differential diagnosis for gastric lesions.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

Fully automated magnetic resonance imaging-based radiomics analysis for differentiating pancreatic adenosquamous carcinoma from pancreatic ductal adenocarcinoma

PURPOSE

To develop and validate an automated magnetic resonance imaging (MRI)-based model to preoperatively differentiate pancreatic adenosquamous carcinoma (PASC) from pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study included patients with surgically resected, histopathologically confirmed PASC or PDAC who underwent MRI between January 2011 and December 2020. According to time of treatment, they were divided into training and validation sets. Automated deep-learning-based artificial intelligence was used for pancreatic tumor segmentation. Linear discriminant analysis was performed with conventional MRI and radiomic features to develop clinical, radiomics, and mixed models in the training set. The models' performances were determined from their discrimination and clinical utility. Kaplan-Meier and log-rank tests were used for survival analysis.

RESULTS

Overall, 389 and 123 patients with PDAC (age, 61.37 ± 9.47 years; 251 men) and PASC (age, 61.99 ± 9.82 years; 78 men) were included, respectively; they were split into the training (n = 358) and validation (n = 154) sets. The mixed model showed good performance in the training and validation sets (area under the curve: 0.94 and 0.96, respectively). The sensitivity, specificity, and accuracy were 76.74%, 93.38%, and 89.39% for the training set, respectively, and 67.57%, 97.44%, and 90.26% for the validation set, respectively. The mixed model outperformed the clinical (p = 0.001) and radiomics (p = 0.04) models in the validation set. Log-rank test revealed significantly longer survival in the predicted PDAC group than in the predicted PASC group (p = 0.003), according to the mixed model.

CONCLUSION

Our mixed model, which combined MRI and radiomic features, can be used to differentiate PASC from PDAC.

Pancreatic adenosquamous carcinoma: A population level analysis of epidemiological trends and prognosis

BACKGROUND

The incidence and mortality of pancreatic adenosquamous carcinoma (PASC) have received little attention. The goal of our study was to explore the overall epidemiological trend of PASC at the population level.

METHODS

The Surveillance, Epidemiology, and End Results database was used to collect the incidence, incidence-based (IB) mortality, and patient details for PASC from 2000 to 2017. The Joinpoint regression tool was used to examine the trends in incidence and IB mortality. The Kaplan-Meier approach was used for survival analysis. Univariate and multivariate Cox regression analyses were used to determine the independent prognostic factors.

RESULTS

We included 815 patients with PASC in the study. The incidence of PASC continuously increased from 2000 to 2017, with an annual percentage change (APC) of 3.9% (95% CI: 2.2%-5.7%, p < 0.05). IB mortality also increased continuously, with an APC of 5.0% (95% CI: 2.5%-7.6%, p < 0.05). Multivariate Cox regression analysis revealed that age, treatment, regional lymph node involvement, and tumor size were independent prognostic factors. Nomograms were created for PASC to predict 1- and 2-year survival probabilities, respectively.

CONCLUSIONS

The incidence and IB mortality of PASC had a sustained and rapid increase, indicating that the preventive and treatment measures for PASC were not ideal. We must identify the significance of this condition as soon as possible, and commit greater attention and resources to PASC research.

Non-enhanced magnetic resonance imaging-based radiomics model for the differentiation of pancreatic adenosquamous carcinoma from pancreatic ductal adenocarcinoma

Purpose

To evaluate the diagnostic performance of radiomics model based on fully automatic segmentation of pancreatic tumors from non-enhanced magnetic resonance imaging (MRI) for differentiating pancreatic adenosquamous carcinoma (PASC) from pancreatic ductal adenocarcinoma (PDAC).

Materials and methods

In this retrospective study, patients with surgically resected histopathologically confirmed PASC and PDAC who underwent MRI scans between January 2011 and December 2020 were included in the study. Multivariable logistic regression analysis was conducted to develop a clinical and radiomics model based on non-enhanced T1-weighted and T2-weighted images. The model performances were determined based on their discrimination and clinical utility. Kaplan-Meier and log-rank tests were used for survival analysis.

Results

A total of 510 consecutive patients including 387 patients (age: 61 ± 9 years; range: 28-86 years; 250 males) with PDAC and 123 patients (age: 62 ± 10 years; range: 36-84 years; 78 males) with PASC were included in the study. All patients were split into training (n=382) and validation (n=128) sets according to time. The radiomics model showed good discrimination in the validation (AUC, 0.87) set and outperformed the MRI model (validation set AUC, 0.80) and the ring-enhancement (validation set AUC, 0.74).

Conclusions

The radiomics model based on non-enhanced MRI outperformed the MRI model and ring-enhancement to differentiate PASC from PDAC; it can, thus, provide important information for decision-making towards precise management and treatment of PASC.

Pancreatic Adenosquamous Carcinoma: A Rare Pathological Subtype of Pancreatic Cancer

Pancreatic adenosquamous carcinoma (PASC) is a rare pathological subtype of pancreatic cancer (PC), with a worse prognosis than pancreatic ductal adenocarcinoma (PDAC). Due to its rarity, our knowledge of PASC and its biological characteristics are limited. In this review, we provide an overview of the histogenesis, genetic features, diagnosis, treatment, and prognosis of PASC, as well as pancreatic squamous cell carcinoma (PSCC). The information provided here may help to clarify our understanding of PASC and provide useful avenues for further research on this disease.

Adenosquamous carcinoma of the pancreas: two case reports and review of the literature

Background

Among the total reported cases of pancreatic duct adenocarcinomas, around 1–2.9% are adenosquamous carcinomas of the pancreas. Due to limited data, preoperative diagnosis is a great challenge for physicians, and it is usually set post-operational, based on the pathologist report. We operated on two cases of adenosquamous carcinoma of the pancreas, which we present alongside the operation and treatment planning.

Case report

A 69-year-old Caucasian female and a 63-year-old Caucasian male presented themselves with jaundice in our department. The abdomen computed tomography and magnetic resonance imaging scans revealed lesions of the pancreas. A pancreas–duodenumectomy was performed in both patients, and the post-operational histology analysis revealed adenosquamous carcinoma of the pancreas head. The patients were discharged in good condition and received further chemotherapy treatment after surgery.

Conclusions

Two case reports of adenosquamous carcinoma of the pancreas are described here, which both underwent surgery resection. The limited available literature on this topic substantially limits the knowledge and guidance on treatment. A summarization of the available literature is attempted, alongside a description of possible fields of future research.

Application of Unenhanced Computed Tomography Texture Analysis to Differentiate Pancreatic Adenosquamous Carcinoma from Pancreatic Ductal Adenocarcinoma

OBJECTIVE

The objective of this study was to investigate the application of unenhanced computed tomography (CT) texture analysis in differentiating pancreatic adenosquamous carcinoma (PASC) from pancreatic ductal adenocarcinoma (PDAC).

METHODS

Preoperative CT images of 112 patients (31 with PASC, 81 with PDAC) were retrospectively reviewed. A total of 396 texture parameters were extracted from AnalysisKit software for further texture analysis. Texture features were selected for the differentiation of PASC and PDAC by the Mann-Whitney U test, univariate logistic regression analysis, and the minimum redundancy maximum relevance algorithm. Furthermore, receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the texture feature-based model by the random forest (RF) method. Finally, the robustness and reproducibility of the predictive model were assessed by the 10-times leave-group-out cross-validation (LGOCV) method.

RESULTS

In the present study, 10 texture features to differentiate PASC from PDAC were eventually retained for RF model construction after feature selection. The predictive model had a good classification performance in differentiating PASC from PDAC, with the following characteristics: sensitivity, 95.7%; specificity, 92.5%; accuracy, 94.3%; positive predictive value (PPV), 94.3%; negative predictive value (NPV), 94.3%; and area under the ROC curve (AUC), 0.98. Moreover, the predictive model was proved to be robust and reproducible using the 10-times LGOCV algorithm (sensitivity, 90.0%; specificity, 71.3%; accuracy, 76.8%; PPV, 59.0%; NPV, 95.2%; and AUC, 0.80).

CONCLUSION

The unenhanced CT texture analysis has great potential for differentiating PASC from PDAC.

Use of ring-enhancement and focal necrosis to differentiate pancreatic adenosquamous carcinoma from pancreatic ductal adenocarcinoma on CT and MRI

PURPOSE

To assess the ability of the ring-enhancing sign and focal necrosis to diagnose adenosquamous carcinoma (ASqC), a variant of pancreatic ductal adenocarcinoma (PDAC), on MRI and CT.

METHODS

The following features of ASqC and conventional PDAC were evaluated on CT and MRI: tumor size, location, margins, borders (non-exophytic, exophytic), and T1 signal intensity. Two readers, blinded to histopathology results, rated their confidence in detecting ring-enhancement and focal necrosis (FN) on a 5-point Likert scale on both MRI and CT. Inter-reader agreement was assessed with Cohen's kappa (k).

RESULTS

A total of 24 patients were included: eight patients with treatment naïve and histologically proven ASqC (six women, mean age: 63, range: 40-75) and 16 patients with PDAC (eight women, mean age: 67, range: 47-83). Statistically significant differences between ASqC and PDAC were seen in tumor size, location, presence of FN, and ring enhancement (p = 0.01-0.037). The readers were more confident in depicting the key differentiating feature ring-enhancement in ASqC on MRI compared to CT (confidence 1.71 ± 0.49 vs. 0.88 ± 0.35, p = 0.017) with moderate inter-reader agreement (k = 0.46 and 0.5, respectively). FN showed substantial inter-reader agreement on MR and moderate agreement on CT (k = 0.67 and 0.5, respectively).

CONCLUSIONS

Compared to CT, MRI depicts ring-enhancement in ASqC with greater reader confidence and FN in ASqC with higher inter-reader agreement. The concurrent presence of these two imaging features should raise high suspicion for ASqC.

Adenosquamous carcinoma of the digestive system: a literature review

Adenosquamous carcinoma (ASC), containing both adenocarcinoma and squamous cell carcinoma components, is rare in the digestive system. Limited data is available on ASC of the digestive system (AS-ASC), and the current evidence is available mainly in the form of case reports and case series. We performed a thorough search of the available literature and compiled a review on the epidemiology, histopathology, pathogenesis, clinical manifestations, diagnosis, treatment, and prognosis of AS-ASC. Non-specific clinical and imaging presentations and low diagnostic accuracy of biopsy lead to difficulties in preoperative diagnosis in a high proportion of patients and high malignancy. The pathogenesis remains obscure. Surgery remains the mainstay of treatment for AS-ASC. The role of chemoradiotherapy as an adjuvant treatment is still inconclusive. Key messages Metastatic linings and the lack of efficacious treatments lead to an unfavorable outcome in AS-ASC patients. Further research could help us understand the pathophysiology of AS-ASCand the unique needs of AS-ASC patients.

Computed Tomography-Based Radiomics Signature for the Preoperative Differentiation of Pancreatic Adenosquamous Carcinoma From Pancreatic Ductal Adenocarcinoma

Purpose

The purpose was to assess the predictive ability of computed tomography (CT)-based radiomics signature in differential diagnosis between pancreatic adenosquamous carcinoma (PASC) and pancreatic ductal adenocarcinoma (PDAC).

Materials and Methods

Eighty-one patients (63.6 ± 8.8 years old) with PDAC and 31 patients (64.7 ± 11.1 years old) with PASC who underwent preoperative CE-CT were included. A total of 792 radiomics features were extracted from the late arterial phase (n = 396) and portal venous phase (n = 396) for each case. Significantly different features were selected using Mann-Whitney U test, univariate logistic regression analysis, and minimum redundancy and maximum relevance method. A radiomics signature was constructed using random forest method, the robustness and the reliability of which was validated using 10-times leave group out cross-validation (LGOCV) method.

Results

Seven radiomics features from late arterial phase images and three from portal venous phase images were finally selected. The radiomics signature performed well in differential diagnosis between PASC and PDAC, with 94.5% accuracy, 98.3% sensitivity, 90.1% specificity, 91.9% positive predictive value (PPV), and 97.8% negative predictive value (NPV). Moreover, the radiomics signature was proved to be robust and reliable using the LGOCV method, with 76.4% accuracy, 91.1% sensitivity, 70.8% specificity, 56.7% PPV, and 96.2% NPV.

Conclusion

CT-based radiomics signature may serve as a promising non-invasive method in differential diagnosis between PASC and PDAC.

Pancreatic Ductal Adenocarcinoma and Its Variants: Pearls and Perils

Pancreatic ductal adenocarcinoma (PDAC), an epithelial neoplasm derived from the pancreatic ductal tree, is the most common histologic type of pancreatic cancer and accounts for 85%-95% of all solid pancreatic tumors. As a highly lethal malignancy, it is the seventh leading cause of cancer death worldwide and is responsible for more than 300 000 deaths per year. PDAC is highly resistant to current therapies, affording patients a 5-year overall survival rate of only 7.2%. It is characterized histologically by its highly desmoplastic stroma embedding tubular and ductlike structures. On images, it typically manifests as a poorly defined hypoenhancing mass, causing ductal obstruction and vascular involvement. Little is known about the other histologic subtypes of PDAC, mainly because of their rarity and lack of specific patterns of disease manifestation. According to the World Health Organization, these variants include adenosquamous carcinoma, colloid carcinoma, hepatoid carcinoma, medullary carcinoma, signet ring cell carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, and undifferentiated carcinoma. Depending on the subtype, they can confer a better or even worse prognosis than that of conventional PDAC. Thus, awareness of the existence and differentiation of these variants on the basis of imaging and histopathologic characteristics is crucial to guide clinical decision making for optimal treatment and patient management.

Adenosquamous Carcinoma of the Pancreas Comprise a Heterogeneous Group of Tumors With the Worst Outcome: A Clinicopathological Analysis of 25 Cases Identified in 562 Pancreatic Carcinomas Resected With Curative Intent

OBJECTIVES

Information of the clinicopathological characteristics and outcome data of patients with adenosquamous carcinoma of the pancreas (ASCAP) remains limited. This study's aim is to describe the clinical, pathological, and molecular characteristics of 25 resected ASCAPs.

METHODS

Of all 25 cases, patient characteristics, follow-up data, and pathological/immunohistological features were reviewed and analyzed.

RESULTS

In this 3-institutional retrospective analysis of 562 pancreatic cancer patients, we identified 25 cases with histologically confirmed ASCAP (4.4%). Follow-up was available in 21 ASCAP and 50 pancreatic ductal adenocarcinoma control patients with a median overall survival of 8.2 and 21 months, respectively. Age, tumor size, localization in the tail, lymph node status, and resection margin seem to be the most significant factors of survival in our ASCAP cohort. In contrast to pancreatic ductal adenocarcinoma, positive expression of p63, keratins K5/14, and the epidermal growth factor receptor are a robust marker profile of these tumors.

CONCLUSIONS

Adenosquamous carcinoma of the pancreas comprises a group of neoplasms in which stage and adverse morphological features contribute to its bad prognosis. Further work must be pursued to improve detection and treatment options to reduce mortality. Specifically, differences in biology might become a target for the development of possible therapies.

18F-FDG PET/CT feature of pancreatic adenosquamous carcinoma with pathological correlation

PURPOSE

To investigate ¹⁸F-FDG PET/CT feature of pancreatic adenosquamous carcinoma (PASC) in contrast with conventional pancreatic ductal adenocarcinoma (PDAC), and its correlation with pathological findings.

PATIENTS AND METHODS

Patients with PASC or PDAC confirmed by surgical pathology, who underwent FDG PET/CT scanning before surgical resection, were retrospectively studied. PASC group and conventional PDAC group included 13 and 104 patients, respectively. Delayed phase of PET/CT scanning was performed in 12 patients with PASC and 99 with PDAC. Maximum standardized value (SUVmax) was measured, and the mean retention index (RI) was calculated by ([PET_120min SUVmax]-[PET _60min SUVmax]) ÷ PET _60min SUVmax × 100%.

RESULTS

On PET/CT, all lesions of PASC group showed intense FDG uptake, and the SUVmax were significantly higher than the lesions of conventional PDAC group both on the early [10.43 ± 5.10 (4.37-24.00) vs. 7.31 ± 3.86 (1.93-21.08), P = 0.011] and delayed phase [13.29 ± 6.04 (5.72-28.16) vs. 8.84 ± 5.14 (1.92-27.58), P = 0.005]. On the delayed phase, all lesions of PASC group had increased SUVmax with positive RI value (27.04% ± 8.87%, 7.14-39.27%). For conventional PDAC group, 81 lesions had increased SUVmax with positive RI value (27.25% ± 19.10%, 1.09-104.49%), while eighteen (18.18%) lesions of PDAC group had slightly decreased SUVmax, and their RI value were negative (- 11.35% ± 13.50%, - 43.17 to - 0.14%). The proliferative index (Ki-67) of lesions of PASC group was positively correlated with both the early (P = 0.034, r = 0.671) and delayed SUVmax (P = 0.019, r = 0.721). The RI value of lesions with adjacent organ invasion in PASC group was significantly higher than those without invasion (33.25% ± 4.92% vs. 20.83% ± 7.49%, P = 0.007).

CONCLUSION

PASC has more intense FDG uptake than conventional PDAC both on early and delayed phase. RI value of PASC was positive. Negative RI value may be helpful for differentiating PDAC from PASC. SUVmax and RI value may be helpful for prediction of its malignancy and invasion.

CT and MR imaging features of pancreatic adenosquamous carcinoma and their correlation with prognosis

PURPOSE

To retrospectively investigate the computed tomography (CT) and magnetic resonance (MR) imaging features of pancreatic adenosquamous carcinoma (PASC) and the association between imaging findings and prognosis.

MATERIALS AND METHODS

CT, MR images of 26 patients with PASC were analyzed. Clinical symptoms, tumor markers, and patients' survival were recorded. Tumor attenuation, enhancement pattern and degree, vessel involvement, adjacent tissue invasion and metastasis were evaluated. The association between imaging features and overall survival (OS) were also assessed using Cox proportional hazards ratio model.

RESULTS

Fourteen masses were found in the head of the pancreas and 12 in the body/tail. The mean tumor size was 4.47 ± 1.76 cm. PASC usually showed ill-defined (96.2%), lobulated (76.9%) and predominantly solid mass (92.3%). Ring enhancement in the peripheral area of the tumor was commonly seen (76.9%). Vessel invasion was seen in 17 cases (65.4%), encasement of adjacent arteries in 7 cases (26.9%), upstream main pancreatic duct (MPD) dilatation in 16 cases (61.5%) and double duct sign in 9 cases (34.6%). Multivariate Cox proportional hazards model demonstrated that patients with vessel invasion may predict a poor prognosis (p = 0.037).

CONCLUSION

PASC tends to be an ill-defined solid mass with peripheral ring enhancement, and relatively poor enhancement in the central area. PASC may also show vessel invasion, vessel encasement and upstream MPD dilatation. Vessel invasion may indicate a poor prognosis.

110 Patients with adenosquamous carcinomas of the pancreas (PASC): imaging differentiation of small (≤ 3 cm) versus large (> 3 cm) tumors

OBJECTIVE

This study examined radiological imaging features of small (≤ 3 cm) and large (> 3 cm) adenosquamous carcinomas of the pancreas (PASC) lesions to better understand the morphology of these lesions.

METHODS

Images from 110 patients with pathologically proven PASC (80 males and 30 females, mean age: 62.6 years) were retrospectively reviewed. Two radiologists analyzed images and reached a consensus regarding the following features: location, shape, margins, presence of solid and necrotic components, rim enhancement, density/intensity during the portal venous phase, invasion of surrounding organs, vascular invasion, venous tumor thrombus formation, and enlarged lymph nodes. Differences in the imaging features between the two groups were evaluated with the Chi-square test or Fisher's exact test.

RESULTS

There were 41 small PASC lesions (mean age: 60.59 years) and 69 large PASC lesions (63.74 years). Statistical analysis demonstrated significant differences in the location, shape, adjacent organ and vessel invasion, and venous tumor thrombus formation (P < 0.05). Small PASC lesions were more frequently detected in the pancreatic head and had an ovoid shape. There was no significant difference in the presence of solid and necrotic components (P = 0.090), including approximately 3/4 of the lesions with necrosis and 1/4 purely solid lesions, enlarged lymph nodes (P = 0.068) and other features.

CONCLUSION

Regardless of the tumor size, 75% of PASC lesions present with central necrosis while 25% are purely solid. Small PASC lesions can be associated with lymph node metastasis at a relatively early stage. Large PASC lesions are likely to invade adjacent tissues and be associated with venous tumor thrombus formation.

Rare Solid Tumor of the Exocrine Pancreas: A Pictorial Review

Numerous other solid primary neoplasms may arise from the pancreas besides primary ductal adenocarcinomas and neuroendocrine tumors. Although diagnosis can be difficult because of the very low incidence of these tumors, knowledge of several, typical, epidemiologic, biological, and imaging features can help obtain a correct diagnosis. This pictorial review describes the features of solid rare primary pancreatic neoplasms on computed tomography and magnetic resonance imaging focusing on characteristics that can help radiologists differentiate them from classical forms of ductal pancreatic adenocarcinoma and neuroendocrine tumors. Cystic pancreatic neoplasms are beyond the scope of the current review.

Two rare cases of pancreatic adenosquamous carcinoma: A review of the literature with focus on radiologic findings

Pancreatic adenosquamous carcinoma (PASC) is a rare, aggressive subtype of pancreatic tumor with a poor prognostic outlook compared to the much more common pancreatic adenocarcinoma. Here we present two cases of the rare PASC and analyze the radiologic findings on computed tomography (CT) and 18F- fluorodeoxyglucose positron emission tomography (FDG-PET).

Both cases involve 62-year-old women presenting with abdominal pain, nausea, and vomiting who on imaging were found to have infiltrating lobular pancreatic masses with ring enhancement on CT and peripheral hypermetabolism with central necrosis on FDG-PET. Location in the pancreas and involvement of adjacent structures differed in the two cases, resulting in varying progressive clinical manifestations.

PASC is a rare subtype of pancreatic cancer with nonspecific imaging findings. Here we presented two cases of PASC supporting previously reported imaging findings suggestive of PASC with additional FDG-PET manifestations and SUV levels, which only few reports have previously described.

Long-term outcomes after an aggressive resection of adenosquamous carcinoma of the pancreas

PURPOSE

Adenosquamous carcinoma (ASC) of the pancreas is a rare malignancy, associated with a poor prognosis after surgical resection, with reported median survival times (MSTs) ranging from 4.4 to 13.1 months. We conducted this study to investigate the long-term outcomes of patients after the resection for ASC.

METHODS

Between 2002 and 2016, a total of 456 patients underwent resection for ASC or adenocarcinoma (AC) of the pancreas. ASC was confirmed in 17 (3.7%) of these patients. We analyzed the clinicopathological characteristics and survival of these 17 patients in comparison with those of patients with AC of the pancreas.

RESULTS

The operative procedures performed were pancreaticoduodenectomy (n = 6) and distal pancreatectomy (n = 11). Seven (41.2%) of the 17 patients underwent combined organ resection. R0 resection was achieved in 16 (94.1%) patients. The 5-year overall survival (OS) rate and MST were 40.3% and 20.9 months, respectively. A squamous component of ≥ 60% (P = 0.001) and R1 resection (P < 0.001) were significantly associated with poor OS for patients with ASC CONCLUSION: This study revealed longer survival and a higher R0 resection rate after aggressive combined resection in our ASC patients than those in previous studies. Although this was only a small series, our findings suggest that local control with aggressive resection may be an effective treatment protocol for ASC patients.

CT and MRI features of undifferentiated carcinomas with osteoclast-like giant cells of the pancreas: a case series

PURPOSE

The purpose of this case series was to describe computed tomography (CT) and magnetic resonance imaging (MRI) features of undifferentiated carcinoma with osteoclast-like giant cells of the pancreas.

METHODS

Institutional ethics review board approval was obtained, and informed consent was waived for this case series. We reviewed CT and MRI of patients with pathologically confirmed undifferentiated carcinoma with osteoclast-like giant cells of the pancreas found in the medical records of our hospital between 2006 and 2016.

RESULTS

Seven patients (3 males and 4 females; age, 59-82 years (mean, 71)) with confirmation by surgical resection (n = 3) or biopsy (n = 4) were identified. They underwent CT (n = 7) and MRI (n = 6). The tumors 26-83 mm in diameter (mean, 44 mm) were located in the head (n = 4) or body (n = 3) of the pancreas. They were demonstrated as lower attenuation areas relative to the adjacent pancreas on CT images obtained in both pancreatic and portal vein phases (n = 7) with a well-defined smooth margin (n = 5). They were demonstrated as hypointense areas relative to the pancreas on T2-weighted images (n = 4) and T2*-weighted images (n = 4) and diffusion-weighted images (n = 3). They contained hemosiderin deposits on histology (n = 7).

CONCLUSIONS

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas might be present as low attenuation areas with a well-defined smooth margin on CT images obtained in pancreatic and portal vein phases, and hypointense areas on T2-, T2*-, and diffusion-weighted images caused by hemosiderin deposits.

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).

Angiogenesis in adenosquamous cancer of pancreas

Adenosquamous carcinoma of the pancreas (ASCP) is an uncommon variant of exocrine pancreatic malignancies, characterized by a histological admixture of adenomatous and squamous cell elements. This cancer is characterized by a poorly differentiated histology and a poorer clinical outcome compared to pancreatic ductal adenocarcinoma (PDAC). Unlike PDAC, that is characterized by a low microvascular density (MVD) and collapsed vasculature, no data are available about angiogenesis in ASPC. Immunohistochemical evaluation of MVD and trypatse-positive mast cells (MCs) were performed on a single case of ASCP compared to PDAC. Moreover, the levels of angiopoietin-1 and -2 (Ang-1, Ang-2), receptor tyrosine kinase with immunoglobulin and epidermal growth factor homology domain-2 (Tie-2), vascular endothelial growth factor A (VEGFA), hypoxia-inducible factor 1 alpha (HIF1A), miR-21-5p, miR-181a-5p, miR-122-5p, and miR-27a-3p were evaluated by real-time PCR. Higher number of tryptase-positive MCs and MVD are observed in the ASCP case compared to PDAC one. Lower levels of miR-122-5p and higher expression of VEGFA, HIF1A and Ang-2 genes were observed in ASCP. Furthermore, lower Ang-1 and Tie-2 transcript levels and higher increases of miR-21-5p, miR27a-3p and miR-181a-5p levels were found in the rarest form of pancreatic carcinoma. Our data demonstrate an important angiogenic activity in ASCP with a putative role of miR-21-5p, miR-181a-5p, miR-122-5p and miR-27a-3p in the regulation of this process.

Pancreatic adenosquamous carcinoma and intraductal papillary mucinous neoplasm in a CDKN2A germline mutation carrier

A 69-year-old woman from a kindred with familial atypical multiple mole melanoma and carrier of a germline mutation in CDKN2A, presented with abdominal pain caused by a solid-cystic pancreatic mass. The patient had an abdominal computed tomography three years before in which there was no evidence of pancreatic lesion. The endoscopic ultrasound guided fine needle aspiration showed adenocarcinoma with squamous component. After surgical resection the final diagnosis was adenosquamous pancreatic carcinoma (ASPC) arising in an intraductal papillar mucinous neoplasm (IPMN). Adenosquamous carcinomas are uncommon in the pancreas and have rarely been described in association with IPMNs. It has worse prognosis than the ordinary pancreatic ductal adenocarcinoma and some distinct features. We review the clinical, imaging, pathologic and molecular aspects of ASPC. Differential diagnosis with contamination, squamous metaplasia and pancreatic metastases from a distant squamous carcinoma is discussed. Besides, the case is an accelerated model of the adenoma (IPMN)-carcinoma sequence probably due to the CDKN2A germline mutation. Somatic CDKN2A mutations are common events in the early steps of sporadic pancreatic cancer, but germline mutation carriers have a significantly higher risk of pancreatic carcinoma.

Solitary Pancreatic Metastasis From Breast Matrix-Producing Carcinoma: A First Case Report

Introduction:

Breast matrix-producing carcinoma (MPC) is a rare histologic type. Pancreatic metastases from breast cancers are also rare. We report the first case of solitary pancreatic metastasis from breast MPC, treated with distal pancreatectomy.

Case presentation:

A 56-year-old woman presented with a 56-mm mass in her right breast and a swollen right axillary lymph node. Both lesions had characteristic early ring enhancement on dynamic magnetic resonance imaging (MRI). Tumor biopsy revealed MPC. She underwent total mastectomy and axillary clearance. On histopathologic examination, the tumor was composed of extracellular matrix with areas of osseous and chondroid differentiation without spindle cells or osteoclasts, surrounded by a dense population of glandular epithelial tumor cells. On immunohistochemical analysis, the tumor cells were positive for AE1/AE3 and cytokeratin 5/6. The final diagnosis was breast MPC with axillary metastasis. Two years later, dynamic MRI displayed a mass in the pancreatic body with early ring enhancement, suspicious for solitary breast MPC metastasis. Distal pancreatectomy was performed. Histopathologic examination revealed bone and cartilaginous matrix with necrosis, surrounded by pleomorphic sarcomatous tumor cells. Tumor cells showed less cytokeratin positivity than the primary breast lesion. These findings were compatible with breast MPC metastasis.

Conclusion:

Solitary pancreatic metastasis from breast MPC has not yet been reported. Surgical resection of malignant pancreatic metastases is controversial; however, considering that breast MPC has limited responsiveness to radiotherapy and chemotherapy, curative resection would be important in this case. The histopathologic features of MPC may reflect enhancement and calcification on radiologic studies.