INTRODUCTION:

Solid pseudopapillary tumor (SPT) is the most recent descriptive term of this characteristic; however, enigmatic pancreatic tumor has previously been designated by many pseudonyms such as solid and papillary tumor, papillary cystic tumor, solid and cystic tumor, solid cystic and papillary epithelial neoplasm ¹. Since degenerating cystic change is characteristic of SPT, SPT must be considered in differential diagnosis of pancreatic cystic neoplasm and with pancreatic pseudocyst.

Solid pseudopapillary tumor (SPT) is a distinctive and rare tumor of the pancreas having low malignant potential and is seen predominantly in adolescent girls and young women but cases from men are also reported ^{2, 3}. An accurate preoperative diagnosis is highly desirable since these patients can have long survival with adequate surgery ⁴. The cytological features of this tumor are highly characteristic and it is possible to differentiate it from other pancreatic tumors with relative ease ⁴. Here we have described four cases of SPT of the pancreas diagnosed preoperatively on fine needle aspiration cytology (FNAC).

MATERIALS AND METHODS:

Ultrasound-guided percutaneous FNAs were performed preoperatively using 22G needle attached to 10 ml plastic syringe by interventional radiologist in Vivekanand Cancer Research Centre, Darbhanga (Bihar). The smears were made on glass slides, fixed immediately in 95% alcohol for subsequent Papanicolaou staining. Additional aspiration material was used for the cell block preparation. The cytomorphological evaluation of smears was done for cellularity, cell type, nuclear details with background and cytologic diagnosis which later on confirmed by histopathology. The immunohistochemistry studies were performed on cell block material using polymer-linked technique using antibodies against cytokeratin, epithelial membrane antigen, vimentin, synaptophysin, neuron-specific enolase and CD-56 each in 1:50 dilution.

RESULTS AND OBSERVATIONS:

The four female patients aged from 20 to 36 years presented at Vivekanand Cancer Hospital, Darbhanga with symptoms related to a mass in the abdomen. The clinical and ultrasonography finding of all the four patients are summarized in Table 1and cytomorphological findings are described in Table 2 and illustrated in microphotographs (Figures 1 and 2).

Table 1: Clinical and ultrasonography study

Case	Age/Sex	Tumor shape	Size (mm)	Clinical result
1	36 yrs/F	Head	67×61	Dyspepsia×2 months
2	24 yrs/F	Tail	100×120	Pain in abdomen O/E lump in abdomen
3	20 yrs/F	Head and body	97×64	Pain in abdomen×2yrs vomiting
4	30 yrs/F	Head & uncinate process upto body	80×70	Lump in abdomen×1month

Table 2: Cytomorphological results

Case	Cellularity	Papillary formation	Bi/Multi-nucleation	Background	Molecular grooves/ convolutions
1	Moderately cellular	+	+	Heteromorphic, foamy cells	Molecular grooves
2	Hyper cellular	+	-	Multinucleated, Giant foamy cells	Molecular grooves
3	Cellular	+	-	Hemorrhagic foamy cells	Molecular grooves; slight convolutions
4	Cellular	+	-	Hemorrhagic	Molecular grooves; convolutions

In summary, smears were moderate to hyper-cellular showing papillae formation, discrete cells and occasional pseudo-rosettes. The papillae formation was seen in all the cases having delicate vascular cores and covered by two or several layers of cells. All the cases showed discrete tumor cells. The individual tumor cells had round to oval eccentric nuclei with bland nuclear chromatin and moderate amount of pale-pink cytoplasm. In all the cases, nuclei showed nuclear grooves and convolution with hemorrhagic background observed. This background showed spongy cells and occasionally multinucleated histiocytic giant cells in this study.

The resection specimens under microscope revealed circumscribed mass with tan to brown variegated cut surface with hemorrhage and necrosis regions. The tumor diameter was 11 cm. The tissue section showed sheets and cords of cells arranged around delicate fibro-vascular septa. There were marked degenerative changes such as formation of microcysts, hemorrhage, aggregates of foamy cells and cholesterol granulomas caused cells arrangement farthest from blood vessels resulted in a pseudo-papillary pattern and pseudo-rosettes. The tumor cells were small to medium in size with round to ovoid uniform nuclei that often were convoluted and grooved having fine chromatin and inconspicuous nucleoli. Cells had eosinophilic cytoplasm. There PAS positive and diastase-resistant hyaline globules were observed in the study.

Figure 1: FNAC smear from case of SPT showing tumor cells arranged in papillary pattern and discrete cells (Pap ×100)

Figure 2: FNAC smear from a case of SPT showing discrete cell (Pap ×200)

The immunohistochemistry showed strong positivity for Vimentin and epithelial markers, while negativity for CD56 and chromogranin in this study. The immunostain result was consistent with previously described immunohistochemistry of this lesion. The difference in clinical, ultrasonography and cytomorphology in patients are age-related and development of cancerous cells during the study period.

DISCUSSIONS:

Solid and pseudo-papillary epithelial tumor (SPT) of pancreas is an uncommon tumor with a distinctive clinic-pathological profile ^5,
6. It is known by a variety of names one of which is “Frantz tumor” as it was first described by Dr. Frantz in 1959 ⁷. The diagnosis should be suspected in any adolescent or young adult female presented with abdominal mass and radiologically cystic or partially cystic well-circumscribed pancreatic mass. Most SPTs behave in a benign or very low grade malignant fashion and the prognosis after surgical excision is excellent. The histogenesis of SPTs is unknown due to discrepancies in immunohistochemical and ultra-structural findings ⁵, however, the tumor is believed to arise from uncommitted epithelial cells that can show exocrine or endocrine differentiation or both ⁸.

A preoperative cytological diagnosis of SPTs is very important due to its implication for management. As these tumors are highly vascular, preoperative accurate diagnosis can avoid complications like hemoperitoneum and intra-operative hemorrhage. This tumor is only locally aggressive, metastasis is rare and so cure from surgical excision is expected in majority of cases. Bondeson et al ⁹ first described the FNAC diagnosis under ultrasound guidance. Since then a few studies have appeared on cytology findings. The cytomorphology of this tumor is highly characteristic and distinct from those of other cystic or solid tumor of pancreas ¹⁰. The cytologic features in our cases of SPTs were very similar to those described in earlier reports ^4,10,11. The highly cellular smears show numerous papillary tissue fragments with slender branching fibro-vascular stalks which are characteristic of this tumor. The tumor cells form two or several layers on the fibro-vascular core.

In this study, papillary fragments and discrete tumor cells were observed. The individual tumor cells have been described as being monomorphous having round to oval eccentric nuclei, bland nuclear chromatin pattern with small nucleoli and exhibiting longitudinal grooves and convolutions. In addition to peri-vascular and papillary fragmentation Jayaram et al ¹² considered the presence of intra-cytoplasmic inclusions as a distinctive feature of this neoplasm which was not seen in the study.

Cappellari et al ¹³ considered the nuclear folds or grooves to be a characteristic of this tumor as seen in this study. Binucleation and multinucleation of tumor cells are also described ¹² which was not present in the study. Mucinous change in the stalks of papillae, foamy cells and multinucleated giant cells are also mentioned earlier in reports^4,10,11.

When one encounters cystic lesion in pancreas, pseudocyst constitutes 80% of cystic lesions. Primary cystic neoplasm such as serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous tumor and SPTs constitutes 20% ¹⁶. The various entities in this group occur more frequently in female but differ in age of presentation. Mucinous cystic neoplasm occurs in a wide age range between 20 and 60 years (mean age 47 years). Patient with serous cystadenoma are much older and mean age at presentation varies from 61 to 68 years. Islet cell tumor of pancreas occurs predominantly in adults and show no sex difference while ductal adenocarcinoma occurs predominantly in elderly and show slight male preponderance (M:F; 1.6:1 ratio). In contrast, SPTs occur almost exclusively in adolescent girls and young women, however it may occur occasionally in elder women and rarely in male ^14,15.

Aspirates from pancreatic pseudocyst is sparsely cellular to acellular with variable amount of debris, inflammatory cells, macrophages, occasional columnar cells and metaplastic squamous cells. Raised serum amylase assay and low CEA level confirm benign nature of lesion. Aspirates from serous cystadenoma which is watery show sparse cellularity with mainly monolayer sheets and occasional papillary fragment of monomorphic cells with vacuolated cytoplasm and bland nuclear chromatin ¹⁵.

FNAC diagnosis of SPTs is the characteristic presentation such as young woman with pancreatic mass, well circumscribed with mixed echo density in ultrasonography and characteristic cytomorphology is relatively easy.

CONCLUSIONS:

SPT is the only locally aggressive tumor with little to rare incidence of metastasis and therefore a surgical cure can be expected in majority of cases. A preoperative accurate cytological diagnosis is very important so that a surgeon is better informed and better prepared to perform the appropriate surgical procedure, which permits the retention of portion of the uninvolved pancreas (if possible) and avoids the development of subsequent diabetes mellitus.

ACKNOWLEDGEMENT:

The authors are thankful to co-operation opted by Director and lab technician of Vivekanand Cancer Hospital, Darbhanga during the investigation period. There is no conflict of interest in authors for publication of this case report.

REFERENCES:

1. Klimstra DS, Wenig BM and Heffess CS (2000): Solid-pseudopapillary tumor of the pancreas: atypically cystic carcinoma of low malignant potential. Seminar Diagn Pathol, 17: 66-80.

2. Bapat KC, Pandit AA, Joshi AS, Vora IM (1992): Aspiration cytology of a papillary cystic neoplasm of pancreas (a case report). Indian J Cancer, 29:100-103.

3. Mohan H, Bal A, Punia RP and Attri AK (2006): Solid and cystic papillary epithelial neoplasm of the pancreas. J Postgrad Med, 52:141-142.

4. Naresh KN, Borges AM, Chinoy RF, Soman CS and Krishnamurthy SC (1995): Solid and papillary epithelial neoplasm of the pancreas: Diagnosis by fine needle aspiration cytology in four cases. Acta Cytol, 39: 489-493.

5. Pettinato G, Manivel JC, Ravetto C, Terracciano LM, Gould EW, Di Tuoro A (1992): Papillary cystic tumor of the pancreas: A clinicopathologic study of 20 cases with cytologic, immunohistochemical, ultrastructural and flow cytometric observations and a review of the literature. Am J Clin Pathol, 98: 478-488.

6. Mendonça ME, Bivar-Weinholtz J and Soares J (1991): Fine needle aspiration cytology of solid and papillary epithelial neoplasm of the pancreas. Acta Cytol, 35: 258-260.

7. Frantz VE (1959): Tumors of the pancreas. In: Anonymous atlas of tumor pathology. Washington DC: Armed Forces Institute of Pathology, pp 32-33.

8. Mendelsohn G (1992): Papillary cystic tumor of the pancreas: An enigma. Am J Clin Pathol, 98: 476-477.

9. Bondeson L, Bondeson AG, Genell S, Lindholm K and Thorstenson S (1984): Aspiration cytology of a rare solid and papillary epithelial neoplasm of the pancreas. Light and electronmicroscopic study of study of a case. Acta Cytol, 28: 605-609.

10. Pettinato G, Di Vizio D, Manivel JC, Pambuccian SE, Somma P and Insabato L (2002): Solid-pseudopapillary tumor of the pancreas: a neoplasm with distinct and highly characterstic cytological features. Diagn Cytopathol, 27:325-334.

11. Geener KJ, Feroze M, Geetha K and Jacob AJ (2002): Papillary cystic tumor of pancreas-report of two cases. Indian J Pathol Microbiol, 45: 99-101.

12. Jayaram G, Chaturvedi KU, Jindal RK, Venugopal S and Kapoor R (1990): Papillary cystic neoplasm of pancreas: Report of a case diagnosed by fine needle aspiration cytology. Acta Cytol, 34: 429-433.

13. Cappellari JO, Geisinger KR, Albertson DA, Wolfman NT and Kute TE (1990): Malignant papillatycystic tumor of the pancreas. Cancer, 66: 193-198.

14. Bardales RH, Centeno B, Mallery JS, Lai R, Pochapin M and Guiter G (2004): Endoscopic ultrasound-guided fine-needle aspiration cytology diagnosis of solid-pseudopapillary tumor of the pancreas: a rare neoplasm of elusive origin but characteristic cytomorphologic features. Am J Clin Pathol, 121:654-62.

15. Leiman G (2005): Pancreas, biliary tract and intraabdominal organs (In: Orell SR, Sterrett GF, Whitaker D editors: Fine needle aspiration cytology). Elsevier, pp 322-324.

Received on 02.04.2023 Modified on 19.04.2023

Research J. Science and Tech. 2023; 15(2):95-98.

DOI: 10.52711/2349-2988.2023.00016