Extrapancreatic solid pseudopapillary neoplasm: report of a case of primary ovarian origin and review of the literature. Int J Gynecol Pathol. 2011;30:539-543. [PMID: 21979589 DOI: 10.1097/pgp.0b013e31821724fb]

Solid pseudopapillary tumor of the pancreas: A systematic review of clinical, surgical and oncological characteristics of 1384 patients underwent pancreatic surgery

BACKGROUND

Pancreatic solid pseudopapillary tumors (SPTs) are rare clinical entity, with low malignancy and still unclear pathogenesis. They account for less than 2% of exocrine pancreatic neoplasms. This study aimed to perform a systematic review of the main clinical, surgical and oncological characteristics of pancreatic SPTs.

DATA SOURCES

MEDLINE/PubMed, Web of Science and Scopus databases were systematically searched for the main clinical, surgical and oncological characteristics of pancreatic SPTs up to April 2021, in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) standards. Primary endpoints were to analyze treatments and oncological outcomes.

RESULTS

A total of 823 studies were recorded, 86 studies underwent full-text reviews and 28 met inclusion criteria. Overall, 1384 patients underwent pancreatic surgery. Mean age was 30 years and 1181 patients (85.3%) were female. The most common clinical presentation was non-specific abdominal pain (52.6% of cases). Mean overall survival was 98.1%. Mean recurrence rate was 2.8%. Mean follow-up was 4.2 years.

CONCLUSIONS

Pancreatic SPTs are rare, and predominantly affect young women with unclear pathogenesis. Radical resection is the gold standard of treatment achieving good oncological impact and a favorable prognosis in a yearly life-long follow-up.

Primary Solid Pseudopapillary Tumor of the Ovary: A Case Report and Review of the Literature

INTRODUCTION

Solid pseudopapillary neoplasms (SPNs) are rare and mainly originate from the pancreas. SPNs originating from the ovary (SPN-O) are extremely rare, and only 13 cases have been reported in the English literature since 2010.

CASE

We report a 31-year-old woman with SPN-O accompanied by multiple metastases in the abdominal cavity. The patient underwent staging surgery and cytoreduction. Furthermore, the multidisciplinary board decided on adjuvant chemotherapy with an FP regimen (fluorouracil plus cisplatin) because a microscopic metastasis was discovered in the peritoneum near the appendix. Next-generation sequencing showed some pathologic mutations of oncogenes/cancer-associated genes, including CTNNB1 and TP53. This is the fourteenth case of SPN-O and the first one to demonstrate the TP53 pathogenic mutant variant in SPN-O. The patient showed 8 months of disease-free survival until February 2024.

CONCLUSION

The combination of R0 cytoreduction with FOLFIRI chemotherapy appears to be an effective and feasible treatment option.

Solid pseudopapillary neoplasm: Report of a case of primary ovarian origin and review of the literature

Background

Solid pseudopapillary neoplasms (SPNs) are uncommon tumors of low malignancy with a generally favorable prognosis, mostly originating from the pancreas. To date, 12 cases of SPNs with a primary ovarian origin (SPN-Os) have been reported globally, and their detailed characteristics have not been fully elucidated.

Case description

We reported the 13th SPN-O case, which occurred in a 52-year-old woman with an 18.5 cm left ovarian mass. Four imaging methods, including ultrasound, computed tomography, magnetic resonance imaging and positron emission tomography, were utilized before surgery. An elevated level of serum cancer antigen 125 was detected and a total hysterectomy plus bilateral salpingo-oophorectomy was performed. Microscopic examination revealed a typical solid pseudopapillary structure. The tumor cells were stained focally for pan-cytokeratin, synaptophysin, CD99 and CD10, while β-catenin, vimentin and CD56 were diffusely expressed. The Ki-67 proliferation index was 3%, and immunohistochemical (IHC) staining for chromogranin-A, inhibin-a, and E-cadherin was negative. No evidence of recurrence or metastasis was observed by clinical and imaging data during a 5-month postoperative follow-up.

Conclusion

This is a report of an unusual case of a primary ovarian SPN with an up-to-date review of SPN-Os. A minimum combination of imaging methods and IHC stains was proposed for SPN-Os, which may prove beneficial in clinical practice.

Case report: A case report and literature review of extrapancreatic solid pseudopapillary neoplasm

Background

Solid pseudopapillary neoplasm (SPN) is a rare tumor with low malignant potential, which typically occurs in the pancreas. Extrapancreatic SPN is also extremely rare worldwide.

Case presentation

We report a case of a 70-year-old woman hospitalized with abdominal pain and bloating. The patient did not have any underlying diseases, such as diabetes, coronary heart disease, or hypertension. More than 30 years ago, the patient underwent surgery for “ectopic pregnancy”. The patient had no family history of hereditary disease, nor did any immediate family members have a history of cancer. Laboratory tests showed that her hemoglobin and albumin levels were low and she had a high level of cancer antigen 125 (CA125). Enhanced computed tomography (CT) showed a large tumor in the abdomen and pelvis. The patient subsequently underwent surgery, and it was found that the tumor was attached to the terminal ileum. Pathological findings suggested that the tumor was an extrapancreatic SPN, with an ectopic pancreas found in the tumor tissue. The patient did not receive chemotherapy or radiotherapy after surgery. After 13 months of follow-up, the patient was admitted again with abdominal pain. CT showed tumor recurrence with extensive systemic metastases. The patient and her family refused reoperation and biopsy, and the patient was discharged after the abdominal pain and anemia resolved.

Conclusion

We report a rare case of extrapancreatic SPN of ileal origin, which could be the first report worldwide. It had aggressive biological features, with recurrence and metastasis 13 months after surgery. For extrapancreatic SPN, the risk of recurrence should be assessed, and for tumors suspected of malignant behavior, a longer follow-up after discharge may be needed. Although SPN generally has a good prognosis after surgery, there is no consensus on whether postoperative chemotherapy and other treatments are needed for patients with high recurrence risk.

Ovarian microcystic stromal tumour: From morphological observations to syndromic associations

Microcystic stromal tumour (MST) is a rare, usually benign, ovarian neoplasm characterised morphologically in its classic form by a distinctive triad of features comprising microcysts, solid cellular regions and fibrous stroma. Variant morphology also occurs, including the presence of nests, tubules, cords, and signet ring cells. Immunohistochemically, this neoplasm is characterised by diffuse nuclear expression of β-catenin, cyclin D1, WT1 and SF1, as well as diffuse staining with FOXL2 and CD10. Inhibin and calretinin are typically negative. At the genomic level, these neoplasms harbour mutually exclusive mutations in CTNNB1 or APC genes with the former being significantly more common. This molecular characteristic raises possible links to other rare ovarian lesions including solid pseudopapillary tumour, signet-ring stromal tumour and Sertoli cell tumour. Rarely, MST is an extracolonic manifestation of familial adenomatous polyposis (FAP) and serves as a sentinel event that could trigger the identification of the syndrome. Herein, we review the published literature on ovarian MST and provide practical advice for pathologists reporting these rare neoplasms.

A 46-Year-Old Woman with Primary Infertility and a Diagnosis of Microcystic Stromal Tumor of the Ovary Confirmed by Histology and Gene Sequencing: A Case Report and Review of the Literature

Patient: Female, 46-year-old

Final Diagnosis: Microcystic stromal tumor of the ovary

Symptoms: Abdominal pain • vaginal bleeding

Medication: —

Clinical Procedure: —

Specialty: Pathology

Endometrioid Tubal Intraepithelial Neoplasia and Bilateral Ovarian Microcystic Stromal Tumors Harboring APC Mutations: Report of a Case

Microcystic ovarian tumor of the ovary is a neoplasm of presumed stromal derivation characterized by CTNNB1 or APC alterations leading to nuclear β-catenin expression. This tumor has been described as unilateral and indolent in previously published series. The recently characterized endometrioid tubal intraepithelial neoplasia (eTIN) is an epithelial proliferation of the tube also characterized by nuclear β-catenin staining, and distinct from high-grade serous precursors. Herein, a case of bilateral ovarian microcystic stromal tumors and multiple left tubal eTINs discovered incidentally in a 41-yr-old woman with previous history of colon cancer is described. Both ovarian and tubal proliferations harbored APC inactivating mutations. Although history of familial adenomatous polyposis or a germline defect could not be confirmed, the history of colon cancer at a young age and the shared APC mutation in both microcystic stromal tumor and eTIN were suggestive of this possibility. Microcystic stromal tumor has been described in the setting of familial adenomatous polyposis syndrome. This case adds to this association by documenting for the first time bilateral ovarian involvement by microcystic stromal tumor. Moreover, it alerts to the possibility of endometrioid neoplasia of the fallopian tube secondary to APC mutations, a previously undescribed phenomenon.

Rare aggressive solid pseudopapillary neoplasm of the ovary with metastatic disease following surgical resection

Extra-pancreatic solid pseudopapillary neoplasms (SPNs) are rare tumours with an overall favourable prognosis and low malignant potential. SPNs with metastatic spread, distant lymph node metastasis and extrapancreatic origin are exceedingly rare. Significant controversy regarding the treatment and the management of metastatic disease exists and, currently, there are no standardised guidelines or treatment recommendations for the use of adjuvant therapy. In this case report, the authors present a patient with widely metastatic SPN of likely ovarian origin with the invasion of the inguinal lymph nodes and multiple abdominal metastatic deposits. Using the currently available literature, the authors discuss treatment options for metastatic SPN of the ovary and highlight the need for continued research in this important field.

Ovarian Solid Pseudopapillary Tumor Resembling Benign Hemorrhagic Cyst on Rapid Frozen Section

Solid pseudopapillary tumors are rare, with the majority of described cases originating in the pancreas. To date, there are only 10 documented reports of primary ovarian solid pseudopapillary tumors. Here, we describe the case of a 24-year-old woman who presented with worsening pelvic pain and dysmenorrhea. Workup demonstrated a right ovarian solid mass on ultrasound and an elevated serum LDH, which raised concerns for dysgerminoma due to her relatively young age. Therefore, she was taken to the operating room and underwent laparoscopic right salpingo-oophorectomy. On initial rapid frozen section, her ovarian cyst had a grossly hemorrhagic appearance with multiple hemosiderin deposits noted microscopically, which suggested a benign hemorrhagic cyst. However, the final pathology was reported as solid pseudopapillary tumor based on several defining histologic characteristics. Most importantly, immunostaining was positive for β-catenin and negative for E-cadherin. This report presents a brief review of the current literature on primary ovarian solid pseudopapillary tumors, including a discussion of expected prognosis after surgical resection, as well as a discussion of the role of immunohistochemistry (IHC) in differentiating ovarian neoplasms in young premenopausal women.

Pancreatic Solid Pseudopapillary Tumor Associated with Elevated DHEA and Testosterone

Solid pseudopapillary neoplasms (SPN) of the pancreas are extremely rare epithelial tumors with low malignant potential. They account for only 1-2% of pancreatic lesions. These masses often go unnoticed and when they become symptomatic it is often due to mass effect on neighboring structures. We encountered an unusual presentation in a healthy 34-year-old female who was found to have elevated dehydroepiandrosterone (DHEA) and testosterone levels during the evaluation of irregular menses. Subsequent abdominal imaging revealed an enhancing 2.7 cm pancreatic tail mass that was concerning for a pancreatic neoplasm. The patient underwent endoscopic ultrasound which confirmed the presence of a hypoechoic, 2.3 x 1.7 cm mass in the pancreatic tail. An intact interface was seen between the mass and adjacent structures, suggesting the absence of local invasion. Fine needle biopsy was performed and cytology was consistent with SPN. The patient later underwent curative distal pancreatectomy, with subsequent normalization of her menses. SPN are generally inactive on laboratory screening modalities (i.e., AFP, CEA, CA 19-9, and CA 125) and our patient showed no evidence of pancreatic insufficiency, pancreatic parenchymal injury, abnormal liver function, or cholestasis. Similarly to our patient, most SPN are asymptomatic. One retrospective study (spanning 15 years) reported vague abdominal pain in ~70% of patients, on initial presentation. Symptoms of tumor mass effect were the second most common. To our knowledge, this is the first reported presentation of elevated DHEA and testosterone levels associated with a solid pseudopapillary tumor in the absence of an underlying adrenal lesion or dysfunction. Despite extensive workup, no alternate etiology or correlatable medical condition could be elucidated for our patient's hormonal dysregulation. We, therefore, recommend further review and investigation into this potential correlative relationship in an effort to guide the future diagnosis and management of this unusual neoplasm.

Solid pseudopapillary neoplasm (SPN) of the testis: Comprehensive mutational analysis of 6 testicular and 8 pancreatic SPNs

BACKGROUND

Recently, we came with the theory of a possible relationship between a group of testicular and pancreatic tumors. We used one case of a pancreatic analogue solid pseudopapillary neoplasm of the testis composed partially of areas reminiscent of solid pseudopapillary neoplasm (SPN) of the pancreas and partially of structures identical to primary signet ring stromal tumor of the testis (PSRSTT) as a connecting link between these two entities. After demonstrating that PSRSTT and pancreatic analogue SPN of the testis share the same immunoprofile and genetic features characteristic for pancreatic SPN, we came to the conclusion that pancreatic analogue SPN of the testis and PSRSTT represent a morphological spectrum of a single entity and that both are related to the pancreatic SPN.

DESIGN

The aim of this study is to present a series of 6 cases of testicular tumors, which lacked the signet ring cell component and were thus morphologically very similar to the SPN of the pancreas. The goal of this study is to compare the genetic background of these testicular tumors that are obviously related to the PSRSTT/pancreatic analogue SPN of the testis with the series of 8 pancreatic SPN.

RESULTS

The mutational analysis revealed an oncogenic somatic mutation in the exon 3 of the CTNNB1 (β-catenin) gene in all analyzable (5/6) testicular and all pancreatic (8/8) tumors. The immunoprofile (positivity with β-catenin, CD10, vimentin, NSE, CD56, and negativity with inhibin, calretinin, chromogranin) was identical in all testicular and pancreatic tumors.

CONCLUSION

This study expanded the morphological spectrum of the PSRSTT/pancreatic analogue SPN of the testis by adding 6 cases without the signet ring cell component. Considering the obvious analogy of PSRSTT/pancreatic analogue SPN of the testis/SPN of the testis and their relationship to the pancreatic SPN we propose the collective term "solid pseudopapillary neoplasm of the testis" for these tumors. The mutational profile of the SPN of the testis and pancreas was the same in both groups of tumors which we consider as a final proof that SPN of the testis is identical to the SPN of the pancreas.

Extrapancreatic solid pseudopapillary neoplasm followed by multiple metastases: Case report

Solid pseudopapillary neoplasm (SPN), also known as Gruber-Frantz tumor, is a rare form of neoplasm that almost exclusively occurs in the pancreas and in young females. While the potential of malignancy is low for SPN, these tumors can mimic other diseases and require a meticulous investigation and a standard treatment by total surgical resection. We present an unusual case of SPN arising in the mesentery of a 40-year-old man with subsequent multiple metastases. Histopathological examination showed similar properties of the mesenteric neoplasm to those of SPN in pancreas. Although the mass was surgically removed, the patient died of recurrent disease 4 years after the initial presentation. We speculate that SPN originates from pancreatic progenitor cells. Further histopathological analyses are required for the prediction of SPN recurrence after resection.

Solid Pseudopapillary Neoplasm of the Pancreas: Clinicopathologic Feature, Risk Factors of Malignancy, and Survival Analysis of 53 Cases from a Single Center

Introduction

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare tumor of low malignant potential. The aim of this study was designed to evaluate the clinicopathologic feature, predictive factors of malignancy, and survival from experience of a single center.

Methods

53 consecutive patients who underwent surgery for a pathologically definitive SPN were retrospectively reviewed.

Results

A total of 53 cases included 7 male cases and 46 female cases with the median age of 35.4 years (14-67). Abdominal pain and mass were the most common clinical presentations. The radiological presentations were consistent with solid and cystic pattern in 18 cases, solid pattern in 25 cases, and cystic pattern in 10 cases. The predominant location of tumor was pancreatic body and tail. The mean size of the tumors was 6.4 cm. Aggressive en bloc resection combined with organ-preserving should be indicated whenever feasible. Follow-up information was available for 48 patients with a median follow-up time of 48 months. The 5-year disease-specific survival was 95.7%. Incomplete capsule was not only the predictive factor of malignancy but also the significant predictor of disease-specific survival.

Conclusion

Incomplete capsule may suggest a malignant SPN and a prognostic indicator of disease-specific survival. We recommend that surgeons consider a more radical resection with an incomplete capsule of tumor.

An extrapancreatic solid-pseudopapillary neoplasm in the greater omentum

A solid pseudopapillary neoplasm (SPN) is an uncommon pancreatic tumour that usually occurs in young women. Tumours outside the pancreas (e.g. in the ovary, retroperitoneum or omentum) are rare. We report a case of an SPN arising from the greater omentum in a 78-year-old male who presented with a month-long history of abdominal pain and a palpable abdominal mass. Laboratory data showed inflammation and anaemia. CT and magnetic resonance imaging revealed a well-defined encapsulated mass measuring 18 cm in the upper right abdomen. The tumour was completely removed via surgery, and pathologic examination confirmed a diagnosis of an SPN in the greater omentum.

CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis

β-catenin (CTNNB1) is a key regulatory molecule of the Wnt signaling pathway, which is important for tissue homeostasis and regulation of cell proliferation, differentiation, and function. Abnormal stabilization and nuclear accumulation of β-catenin as a consequence of missense mutations or alternative molecular mechanisms occurs at a high frequency in a variety of epithelial cancers. In mesenchymal neoplasia, the role of β-catenin has been traditionally considered limited to desmoid-type fibromatosis. However, the spectrum of β-catenin-driven (β-catenin-altered) neoplasia of mesenchymal origin has been steadily widening to include, in addition to desmoid tumors, a variety of benign and intermediate-biology neoplasms of soft tissue (intranodal palisaded myofibroblastoma), head and neck (juvenile nasopharyngeal angiofibroma and sinonasal hemangiopericytoma/glomangiopericytoma), and ovarian (microcystic stromal tumor) origin. In addition, several old and newly reported distinctive site-specific β-catenin-driven parenchymal neoplasms of uncertain histogenesis have been well characterized in recent studies, including solid-pseudopapillary neoplasm of the pancreas and its recently described ovarian counterpart, sclerosing hemangioma of lung and calcifying nested stromal-epithelial tumor of the liver. This review addresses the most relevant pathobiological and differential diagnostic aspects of β-catenin-altered neoplasms with emphasis on site-specific histologic and biological variations. In addition, the morphologic overlap and analogy as well as distinctness between these uncommon tumors will be presented and discussed. Furthermore, a note is made on association of some of these lesions with hereditary tumor syndromes, in particular with the familial adenomatous polyposis coli.

Microcystic stromal tumour of the ovary: frequent mutations of β-catenin (CTNNB1) in six cases

AIMS

To analyse the clinicopathological, immunohistochemical and β-catenin (CTNNB1) mutation characteristics of six cases of microcystic stromal tumour of the ovary (MCST).

METHODS AND RESULTS

Six Chinese patients with MCST who ranged in age from 29 to 69 years (mean 50 years) were included in the study. Five patients were detected with a pelvic mass during routine health examinations and one patient presented initially with opsomenorrhoea. All tumours involved the left ovary, with solid-cystic cut surface in five cases and cystic cut surface in one case. Microscopically, microcysts, solid nests and hyaline degenerated fibrous stroma were variably mixed. Immunohistochemically, the tumour cells in all cases were diffusely positive for CD10, vimentin and WT-1 and negative for α-inhibin and calretinin. β-catenin expression was observed in both the nucleus and the cytoplasm in five cases and only in the cytoplasm in one case. The results of CTNNB1 mutation analysis revealed four missense point mutations in four cases, which were c.97T>C, c.101G>A, c.110C>G and c.122C>T.

CONCLUSIONS

MCST shows a unique morphology with characteristic immunophenotype. β-catenin expression in the nucleus and β-catenin mutations were identified in the majority of cases, which suggests that the Wnt/β-catenin pathway may play a crucial role in the tumorigenesis of MCST.

β-catenin mutation in ovarian solid pseudopapillary neoplasm

Primaly solid pseudopapillary neoplasm (SPN) of the ovary is a rare tumor; recently 6 cases have been reported. Its pathogenesis, however, remains largely unclear. We report an additional case of primary ovarian SPN of an 18-year-old girl. The aim of this study is to define the difference between pancreatic and ovarian SPN by histological and molecular examination. Microscopically the tumor predominantly showed a solid pattern and focally a pseudopapillary pattern. The tumor cells showed two patterns of abundant eosinophilic cytoplasm and intracytoplasmic vacuoles. Immunohistochemistry of the tumor was positive for β-catenin (nuclear and cytoplasmic reactivity), α1-antitrypsin, vimentin, CD56, synaptophysin (focal weak), CD10. Mutation analyses revealed a point mutation, c.110C >T, in exon 3 of the the β-catenin gene (CTNNB1), which causes the replacement of serine with phenylalanine at codon 37. A Ser37 point mutation is known to be one of the oncogenic somatic mutations in pancreatic SPN and the major oncogenic β-catenin mutation. Ovarian SPN of our case was similar to pancreatic SPN histologicaly and had the same genomic characteristics. We expected that both ovarian and pancreatic SPNs shared the same oncogenesis related to Wnt/β-catenin pathway for tumorgenesis.

Solid pseudopapillary neoplasm of the pancreas in children: a 15-year experience and the identification of a unique immunohistochemical marker

PURPOSE

To review our 15-year experience in the management of children with solid pseudopapillary neoplasm (SPPN) of the pancreas at a single pediatric institution, to delineate a unique immunohistochemical marker for SPPN, and to analyze cumulative data on this rare entity in the literature.

METHODS

We did a retrospective analysis of the demographic data, clinical presentation, immunohistochemical characteristics, surgical approach, and long-term outcomes of all patients diagnosed with SPPN between 1997 and 2012.

RESULTS

There were 6 patients in the series, 5 females and 1 male. Median age at presentation and at surgery was 15 years (11-18 years). Abdominal pain was the presenting symptom in 5 cases and jaundice in 1 case. Two patients had a pancreatic head tumor and underwent a pylorus-preserving pancreaticoduodenectomy. Two patients had the tumor in the pancreatic tail and underwent a distal pancreatectomy with splenectomy. Two patients had the tumor in the pancreatic body and underwent a distal pancreatectomy with splenectomy in one case and with preservation of the spleen in the other. All tumors were completely resected with pathologic margins free of disease. The median maximum diameter was 6.8 cm (3 to 15 cm). On immunohistochemistry the tumors exhibited different combinations of non-specific markers like chromogranin, vimentin and neuron-specific enolase, but all tumors showed the highly SPPN-specific paranuclear dot-like immunoreactivity pattern for CD99 in the solid as well as in the pseudopapillary areas. No patient had metastasis at presentation. Median follow-up was 6.5 years (6 months to 15 years). There were no recurrences, no long-term metastasis, and all patients are disease-free.

CONCLUSION

Our series supports the concept that complete resection is necessary to achieve the best possible long-term results. Additionally, we demonstrate that SPPN exhibits a very unique immunostaining pattern for CD99 that is present in all cases.

Extrapancreatic solid pseudopapillary neoplasm: Report of a case of primary retroperitoneal origin and review of the literature

Solid pseudopapillary tumors (SPTs) occurring as primary tumors outside the pancreas are exceedingly rare. The present study reports such a case occurring as a non-functional adrenal tumor in a 22-year-old female. The tumor was completely removed from the retroperitoneum by laparoscopic surgery. A well-defined, encapsulated tumor measuring 6×6×5 cm was histologically characterized by a combination of the solid and pseudopapillary growth patterns of tumor cells with eosinophilic cytoplasm. Ectopic pancreatic tissue was also found histologically within the resected tumor. On immunostaining, the tumor was positive for progesterone receptor, CD56, cytokeratin and CD10. The morphological and immunohistochemical features were compatible with those of SPT. To the best of our knowledge, this is the first case report of extrapancreatic SPT with evidence of a pre-existing ectopic pancreas in the retroperitoneum. A review of the published English literature uncovered 12 cases of extrapancreatic SPTs, and revealed that extrapancreatic SPTs are likely to have a favorable clinical course and a clinical profile similar to their pancreatic counterparts.

Cercariform cells: another cytologic feature distinguishing solid pseudopapillary neoplasms from pancreatic endocrine neoplasms and acinar cell carcinomas in endoscopic ultrasound-guided fine-needle aspirates

BACKGROUND

Solid pseudopapillary neoplasm (SPPN) is a rare tumor of unknown origin that occurs predominantly in the body or tail of the pancreas in young women. The authors recently identified cercariform (Greek: tailed) cells, similar to those described in urothelial carcinomas, as a consistent cytologic feature in ultrasound-guided fine-needle aspiration (EUS-FNA) samples from SPPNs. The objective of the current multi-institutional study was to define the value of these cells in the differential diagnosis of SPPN with other neoplasms characterized cytologically by the presence of monotonous, uniform cells in pancreatic aspirates: pancreatic neuroendocrine tumors (Pan-NETs) and acinar cell carcinomas (ACCs).

METHODS

The files of 4 academic hospitals were searched for SPPNs, Pan-NETs, and ACCs that were diagnosed by EUS-FNA. The slides were reviewed, and several cytologic features were recorded semiquantitatively to identify discriminating features between SPPNs, Pan-NETs, and ACCs.

RESULTS

From the analysis of 18 SPPNs, 4 ACCs, and 20 Pan-NETs, the following cytologic features were identified as common to all 3 neoplasms: single cells and rosettes/acinar cell groups, round-to-plasmacytoid cells, pale-to-granular cytoplasm, fine vacuoles, and binucleated cells. Papillary structures, cercariform cells, large cytoplasmic vacuoles, reniform nuclei, hyaline globules/magenta-colored material, and degenerative features (cholesterol crystals, calcifications, foam cells, or giant cells) were significantly more common in SPPNs. Prominent nuclear grooves were encountered in only 4 of 18 SPPNs.

CONCLUSIONS

The current results indicated that the presence of cercariform cells is another useful clue for the cytologic diagnosis of SPPN in challenging cases.

A case of extrapancreatic solid pseudopapillary tumor in the retroperitoneum

Solid pseudopapillary tumor (SPT) is an uncommon epithelial neoplasm of the pancreas. Very rarely it has also been described outside the pancreas. We report such a case located in the right adrenal site in a 37-year-old woman, describing the computed tomography features of the neoplasm. The image features of extrapancreatic SPT in our case are compatible with those of conventional pancreatic SPTs. Although it is still difficult to make an accurate preoperative diagnosis of an extrapancreatic SPT, the presence of an encapsulated solid and cystic mass especially with widely distributed calcifications is at least suggestive of the diagnosis. Being aware of the rare occurrence of primary SPT outside the pancreas may help improve the diagnostic specificity of the disease.