Implications of imaging, morphologic, and immunohistochemical features of pancreatic perivascular epithelioid cell tumor: case report and comprehensive literature review

Abstract

Background

Perivascular epithelioid cell tumor (PEComa) of the pancreas is a rare tumor of pancreatic mesenchymal origin with malignant potential. Critical to appropriate clinical management is determining whether the tumor is benign or malignant. Because of its rarity, morphologic and histologic characteristics and limited patient follow-up of pancreatic PEComa have precluded precise definition of malignancy. However, because malignant pancreatic PEComa appears to be distinctly uncommon, further improvements characterizing its preoperative imaging features could facilitate use of diagnostic endoscopic ultrasound biopsy and perhaps ablative treatment. This paper presents a case of pancreatic PEComa treated at the Affiliated Hospital of North Sichuan Medical College and includes a systematic literature review with special emphasis on the key imaging features of pancreatic PEComa.

Case presentation

In February 2024, a woman in her 50s was admitted to the hospital with subxiphoid discomfort. Magnetic resonance imaging (MRI) of the upper abdomen revealed a round, solid mass in the pancreatic uncinate process. The patient underwent pancreatic mass resection and pancreaticojejunostomy, and the diagnosis of pancreatic PEComa was confirmed through pathological examination.

Conclusions

Imaging examinations appear valuable for a tentative diagnosis of pancreatic PEComa. Key imaging features include its frequent occurrence in the pancreatic head, typically small to moderate size, “pushing” as opposed to infiltrative growth pattern with well-defined margins, and the presence of a capsule. The lesions are usually solid and often exhibit mild to moderate heterogenous enhancement during the arterial phase, with reduced enhancement in the portal and delayed phases.

Background

In 1992, Bonetti et al. [1] first proposed the concept of perivascular epithelioid cells (PECs), and found that in addition to angiomyolipoma (AML) and clear cell “sugar” tumor (CCST), PECs expressing the melanin marker HMB45 are also present in pulmonary lymphangiooleiomyomatosis (LAM). In 1996, Zamboni et al. [2] reported a case of pancreatic clear cell tumor, which was named perivascular epithelioid cell tumor (PEComa) because the tumor had PEC differentiation and expressed the melanin marker HMB45. The 2013 edition of the WHO Classification of Soft Tissue and Bone Tumors defines PEComa as mesenchymal-derived tumors with local association of tumor cells to the vessel wall, often expressing melanin and smooth muscle markers. The PEComa family of tumors at that time included AML, CCST, LAM, and tumors from soft tissue and visceral sites with similar histomorphology and immunophenotype that could not be classified into a specific type (such tumors were named PEComa-not otherwise specified, PEComa-NOS) [2, 3]; the original family member, the clear cell myomelanocytic tumor of the ligamentum teres and falciform ligament (CCMT), was removed and existed only as a synonym for PEComa. The 2020 edition of the WHO classification of soft tissue tumors has been further updated: the diagnostic terms CCMT and lung CCST are no longer recommended, and the two are no longer used as independent histological types; at the same time, the expression “familial tumors” in PEComa is also removed, and PEComa includes only PEComa-NOS, AML, and LAM.

PEComas are commonly found in the uterus, gastrointestinal tract, and kidneys, but their occurrence in the pancreas is quite rare [4]. Most prior studies of pancreatic PEComa have focused on the pathogenesis and pathomechanism, with limited reports on imaging features. We report a case of pancreatic PEComa treated at the Affiliated Hospital of North Sichuan Medical College together with systematic review of the literature from the first documented pancreatic PEComa case to the present. The analysis focuses on the imaging features of pancreatic PEComa to support its clinical diagnosis and potentially provide the basis for endoscopic ultrasound biopsy and local ablative treatment as an alternative to a much more extensive pancreatic cancer operation.

Case presentation

In February 2024, a woman in her 50s presented with subxiphoid discomfort accompanied by belching, loss of appetite, and an aversion to oily and greasy foods. She denied radiation of pain to the shoulder or back, chills, fever, jaundice, nausea, vomiting, acid reflux, bloating, lethargy, or fatigue. She had no history of smoking, alcohol consumption, or family genetic disorders. She was known to be hypertensive, previously had undergone cholecystectomy, but had no history of trauma. Imaging evaluation included upper abdominal magnetic resonance (MR) examination (Fig. 1), which revealed an abnormal round, 3.0 cm × 2.7 cm × 3.1 cm mass in the uncinate process of the pancreas. The lesion showed low signal on T1WI (Fig. 1A), slightly lower signal on T2WI and fat-suppressed T2WI, with patchy areas of slightly higher signal (Fig. 1B and D). It demonstrated a high signal on DWI (Fig. 1E and F), mild heterogeneous enhancement in the arterial phase, with patchy areas of prominent enhancement and clear capsule enhancement (Fig. 1G). There was reduced enhancement in the portal and delayed phases, with signal intensity lower than normal pancreatic parenchyma (Fig. 1H and I). The lesion did not infringe on the adjacent superior mesenteric vein. There was no dilation of the main pancreatic duct, and the peripancreatic fat space was clearly defined. The lower common bile duct wall was slightly thickened with delayed enhancement, and the intra- and extrahepatic bile ducts were mildly dilated at the upper level. No enlarged lymph nodes were identified in the upper abdomen.

Fig. 1.

MR findings of pancreatic PEComa (the lesions are indicated by the red arrow). T1WI (A) shows a circular mass with low signal on the uncinate process of the pancreas. T2WI (B) and fat-suppressed T2WI (C-D) show the mass is mainly low signal, and the patchy slightly high signal is found in it The tumor showed high signal on DWI(E) and low signal on ADC (F). The tumor showed slightly uneven enhancement in the arterial stage, the capsule was significantly strengthened (G), and the degree of enhancement was reduced in the portal stage (H) and venous stage (I), and the signal was lower than that in the normal pancreatic parenchyma. MR = magnetic resonance

Results

Surgical specimen

The patient underwent pancreatic mass resection and pancreaticojejunostomy. Intraoperatively, the tumor appeared to be approximately 3 cm in diameter, located in the uncinate process of the pancreas. The tumor had a soft texture, was adherent to but not invasive of the superior mesenteric vein, and the pancreatic duct was not dilated. Small millet-like nodules were identified on the peritoneum of the abdominal and pelvic cavities, omentum, and intestinal wall.

Gross specimen

The resected pancreatic tumor measured 3.2 × 2.2 × 0.9 cm, with no clear and complete capsule, the cross-sectional surface is grayish-gray-red, the solid nature is soft, and the focal matter is tough. Small nodules, approximately 0.1–0.2 cm in diameter, were scattered within the resected omentum.

Pathological examination

Under the microscope, epithelioid cells can be seen nested around the blood vessels, the cells are polygonal, the cytoplasm is rich, rich in powder-dyed granules or cytoplasm translucent. Round nuclei with obvious nucleoli, a few cells can see binucleation, pathological nuclear division is < 1/50HPF, and no definite necrosis is observed. Immunohistochemical analysis of the pancreatic tumor (Fig. 2) showed HMB45 (+), MelanA (+), TFE3 (+, weakly positive), CK (-), S-100 (+, scattered), Ki-67 (+, about 5%), SMA (+), Desmin (+), CD56 (-), and Syn (-).The patient was not stained with chromogranin A and Sox10. Granulomatous nodules were identified in the fibrous adipose tissue from the omentum.

Fig. 2.

Pathological section and immunohistochemistry of specimens. A. H&E (×100). The nuclei of tumor cells are round or oval, with small nucleoli. The density of tumor cells is significantly increased, and the nuclei show atypia, but the atypia is not severe and nuclear division figures are rare; B. Tumor cells expressing HMB-45 (×100); C. Tumor cells immunophenotypically positive for the melanocyte marker MelanA (×100); D. Tumor cells immunophenotypically positive for the smooth muscle marker SMA (×100)

Postoperatively, the patient developed hypokalemia and suffered temporary drainage tube bleeding. After adequate hemostasis of the bleeding and potassium supplementation, she stabilized and was discharged. One month later, the patient was readmitted with recurrent drainage tube bleeding which was again satisfactorily treated and she was promptly discharged. At recent follow-up, her only complaint was occasional bloating.

Diagnosis

PEComa in the uncinate process the pancreas.

Follow-up

No recurrence or distant metastasis was observed during 15-months of follow-up.

Discussion

PEComas of the pancreas are extremely rare mesenchymal tumors, with only 25 cases reported in the English literature. The first case of PEComa was described in 1996 by Zamboni et al., who coined the term “pancreatic sugar tumor” [2]. However, it was not until 1992 that Bonetti et al. coined the term “perivascular epithelioid cell” based on its immunoreactivity and pathological characteristics [1]. We comprehensively analyzed the clinical and pathological data from 26 cases, including the one presented in this study (Table 1) [2, 5–27]. The mean age of the patients was 48.6 ± 14.5 years (range: 17–74 years), with a male-to-female ratio of 1:4.2. This suggested that the incidence of PEComa was significantly higher in females, possibly indicating a link to sex hormones as a potential risk factor. The main initial symptom of pancreatic PEComa was abdominal pain, though a few cases were discovered during physical or follow-up examinations for other conditions. Most lesions were located in the pancreatic head, with a mean size of 3.9 ± 2.6 cm (1.0–11.5 cm). Pathologically, pancreatic PEComa primarily consisted of epithelioid and spindle cells, with capsule invasion observed in some cases. HMB-45 and Melan-A tumor markers were consistently present. The tumor appeared to grow slowly, and most cases showed no signs of malignancy. Follow-up results were not detailed for four patients. Two patients had liver metastasis, while 20 patients showed no recurrence or distant metastasis. However, Nagata [11] and Mourra [12] reported cases of liver metastasis after PEComa surgery, highlighting the importance of prolonged, regular follow-up.

Table 1.

Summary of previous clinical features of PEComas

Author	Year	Sex	Age, years	Location	Size(cm)	Malignancy	Symptom	Treatment	HMB-45	α-SMA	Melan-A	Ki-67%	Morphological features	Histology type	Recurrence	Follow up, month
Zamboni et al. [2]	1996	F	60	Body	2.0	No	Upper abdominal pain	DP	+	+	N.A	< 1%	Epithelioid	Sugar tumor of the pancreas	-	3
Ramuz et al. [5]	2005	F	31	Body	1.5	No	Abdominal pain	SPDP	+	+	+	< 1%	Epithelioid	Sugar tumor of the pancreas	-	9
Périgny et al. [6]	2007	F	46	Body	1.7	No	Diarrhea	Enucleation	+	+	N.A	N.A	Spindle > epithelioid	PEComa	-	3
Hirabayashi et al. [7]	2009	F	47	Head	1.7	No	Abdominal pain	PPPD	+	+	+	< 1%	Spindle	PEComa	-	12
Baez et al. [8]	2009	F	60	Body	3.5	No	Abdominal bulge	DP	+	+	+	N.A	Epithelioid + Spindle	PEComa	-	7
Finzi et al. [9]	2011	F	62	Head	2.5	No	None	Total excision	+	+	N.A	8%	Epithelioid	PEComa	-	5
Zemet et al. [10]	2011	M	49	Head	4	No	Fever, cough and malaise	PPPD	+	+	+	< 1%	Epithelioid smooth muscle cells	Sugar tumor of the pancreas	-	10
Nagata et al. [11]	2011	M	52	Head	4	Yes	Abdominal pain	PD	+	N.A	+	N.A	Epithelioid	PEComa	Liver	27
Mourra et al. [12]	2013	F	51	Head	6	Yes	Abdominal pain; jaundice	PD	+	-	N.A	/	Epithelioid	PEComa	Liver	6
Al- Haddad et al. [13]	2013	F	38	Uncinate	1.8	No	Epigastric pain	PD	+	+	N.A	N.A	Epithelioid + spindle	PEComa	N.A	N.A
Okuwaki et al. [14]	2013	F	43	Body and tail	10	N.A	Abdominal pain	DP	+	+	+	< 5%	Spindle	PEComa	-	7
Petrides et al. [15]	2015	F	17	Head	4.2	No	Melena; anemia	PPPD	+	+	+	N.A	Epithelioid + spindle	PEComa	-	18
Jiang et al. [16]	2016	F	50	Head and uncinate process	2.0	No	None	PPPD	+	+	+	1%	Epithelioid + spindle	PEComa	-	14
Mizuuchi et al. [17]	2016	F	61	Head and body	7	No	Abdominal pain	PD	+	-	N.A	< 1%	Epithelioid	PEComa	-	144
Collins et al. [18]	2016	F	54	Head and body	2.6	No	Abdominal pain	MD	+	+	+	< 1%	Epithelioid	PEComa	-	27
Zhang et al. [19]	2017	F	43	Head	11.5	Yes	Abdominal pain	PD	+	N.A	-	5%	Epithelioid + spindle	PEComa	-	18
Sangiorgio et al. [20]	2018	F	47	isthmus	3.0	N.A	None	N.A	+	+	N.A	N.A	N.A	PEComa	N.A	N.A
Sangiorgio et al. [20]	2018	F	70	Body	1.0	N.A	None	N.A	+	+	+	N.A	N.A	PEComa	N.A	N.A
Uno et al. [21]	2019	F	49	Tail	4.0	No	None	Underwent distal pancreatectomy	+	+	+	< 5%	Epithelioid + spindle	PEComa	-	12
Gordon et al. [22]	2019	M	17	Head	5.5	Yes	weight loss, asthenia and flu-like syndrome	mTOR inhibitor	+	+	+	10%	Epithelioid	PEComa	-	42
Ulrich et al. [23]	2020	F	49	Body	2.5	No	Abdominal pain; intermittent watery diarrhea	LLPS	+	+	+	N.A	Epithelioid + spindle	PEComa	N.A	N.A
Geng et al. [24]	2021	F	40	Body	2.3	No	None	PPPD	+	+	+	5%	Epithelioid or spindle	PEComa	-	30
Almousa et al. [25]	2023	F	27	Tail	4	No	Abdominal pain	LDPS	+	+	N.A	N.A	Epithelioid + spindle	PEComa	-	84
Nogueira Sixto et al. [26]	2023	M	68	Head	7.8	uncertain	Abdominal pain	PPPD	+	+	+	N.A	Epithelioid	PEComa	-	18
Tsukita et al. [27]	2024	M	74	Tail	2.7	No	Abdominal pain	DP	+	+	+	N.A	Epithelioid or spindle	PEComa	-	13
Our	2024	F	59	uncinate process	3.0	No	Subxiphoid discomfort	Pancreatic tumor excision	+	+	N.A	5%	Epithelioid + spindle	PEComa	-	6

F = female, M = Man, SPDP = splenic-preserving distal pancreatectomy, PPPD = pylorus-preserving pancreaticoduodenectomy, DP = distal pancreatectomy, PD = pancreatoduodenectomy, MD = middle pancreatectomy, LLPS = laparoscopic left-sided pancreatectomy with splenectomy, LDPS = laparoscopic distal pancreatectomy with splenectomy, PEComa = perivascular epithelial cell tumor, HMB-45 = human melanoma black 45,SMA = smooth muscle actin

Most case reports in the literature have focused on the clinical and pathological characteristics of PEComa, with limited detailed descriptions of its imaging manifestations. Therefore, we reviewed the existing literature and summarized the imaging characteristics of 25 patients with PEComa as reported by ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) (Table 2) [2, 5–27]. This is the first detailed and comprehensive review of the imaging characteristics of PEComa in the published literature.

Table 2.

Summary of previous radiographic characteristics of of PEComas

Author	Shape	Boundary	Envelope	Nature	Dilated main pancreatic duct	Dilated bile duct	Density	Signal	Ehoic	Reinforcement mode	Enlarged lymph nodes	Invasion	Metastases
Zamboni et al. [2]	Round	Clear	+	Solid	N.A	N.A	Uniform density	N.A	Homoechoic	N.A	N.A	-	-
Ramuz et al. [5]	Round	Clear	+	Solid	N.A	N.A	Uniform density	Isointensity	Homoechoic	N.A	-	Adjacent liver and superior mesenteric vein	-
Périgny et al. [6]	Round	Clear	N.A	Solid	-	-	N.A	N.A	N.A	CT: Mild enhancement in arterial phase and decreased enhancement in portal venous phase	-	-	-
Hirabayashi et al. [7]	Round	Clear	+	Solid	-	-	N.A	hypointensity	Hypoechoic and punctate hyperechoic	N.A	N.A	-	-
Baez et al. [8]	Round	Clear	+	Solid	+	N.A	Uniform density	N.A	High and low mixed echoes	CT: Mild enhancement in arterial phase and decreased enhancement in portal venous phase	-	-	-
Finzi et al. [9]	Round	Clear	+	Solid	-	N.A	Uniform density and slightly hyperdense	N.A	N.A	CT: Without enhancement	N.A	-	-
Zemet et al. [10]	N.A	Clear	N.A	Solid	+	+	Calcified foci in head of pancreas	N.A	Hyperechoic and calcified lesion	N.A	-	Compression of descending duodenum and common bile duct	-
Nagata et al. [11]	N.A	N.A	+	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	+
Mourra et al. [12]	N.A	Unclear	N.A	N.A	N.A	+	N.A	N.A	N.A	N.A	-	Invasion of duodenal wall with extensive necrosis and vascular invasion	+
Al- Haddad et al. [13]	N.A	Clear	+	Solid	-	-	N.A	N.A	Hypoechoic	N.A	N.A	-	-
Okuwaki et al. [14]	Irregular	Clear	+	Cystoid-material	+	-	Hyperdense inside the tumor	N.A	Hypoechoic	CT: A lack of contrast enhancement of arterial phase, the degree of enhancement during the procrastinated phase mitigated the integrity of the normal pancreatic tissue	N.A	Contact pancreas and stomach	-
Petrides et al. [15]	Round	Clear	+	Solid	+	+	N.A	N.A	N.A	CT: Marked enhancement in arterial phase, isodense in portal venous phase	-	-	-
Jiang et al. [16]	Round	Clear	+	Solid	-	-	N.A	Hypointensity on T1WI; isointensity on T2WI	Heterogeneous hypoechogenicity	CT: Marked enhancement in arterial phase, isodense in portal venous phase	-	-	-
Mizuuchi et al. [17]	gourd-shaped	Clear	+	Solid	+	-	Hypodense	Heterointensity	Hypoechoic Heterogeneous and included a cystic component	MRI: Heterogeneous enhancement	-	-	-
Collins et al. [18]	N.A	Clear	N.A	N.A	N.A	N.A	N.A	N.A	a whorled-like pattern of hyperechogenicity	N.A	N.A	N.A	N.A
Zhang et al. [19]	Oval- shaped	Unclear	+	Solid	+	-	Mixed density	N.A	Hypoechoic	CT: Mild enhancement in arterial phase and decreased enhancement in portal venous phase	-	Liver and superior mesenteric vein	-
Sangiorgio et al. [20]	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A
Sangiorgio et al. [20]	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A
Uno et al. [21]	Round	Clear	+	Solid	-	N.A	Uniform density	Slightly hyperintensity on T2WI Clearly hyperintensity on DWI	Hypoechoic	CT: Enhancement pattern was the same as spleen, capsule was significantly enhanced	N.A	-	-
Gordon et al. [22]	Irregular	Clear	N.A	Solid	-	-	N.A	Heterointensity and patchy necrotic areas in the lesion	Heteroechoic	MRI: Mild heterogeneous enhancement with patchy areas of no enhancement	-	Duodenal wall	-
Ulrich et al. [23]	Round	Clear	+	Solid	-	-	Hypodense	Hypointensity on T1WI	Hypoechogenic	EUS: Persistent arterial phase enhancement, late hypoechogenicity	-	-	-
Geng et al. [24]	Round	Clear	N.A	Cystoid-material	-	-	Uniform density	N.A	N.A	CT: Moderately progressive enhancement	N.A	N.A	N.A
Almousa et al. [25]	oval-shaped	Clear	+	Solid	-	-	N.A	N.A	N.A	CT: Portal phase reduced as much as pancreas	-	-	-
Nogueira Sixto et al. [26]	N.A	Clear	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	N.A	-	-
Tsukita et al. [27]	Round	Clear	+	Solid	-	N.A	Uniform density	Hypointensity on T1WI; isointensity on T2WI	N.A	CT: No significant enhancement was observed in portal venous phase and arterial phase; edge enhancement was observed in delayed phase	-	-	-
Our	Round	Clear	+	Solid	-	+	N.A	Hypointensity on T1WI; Hypointensity on T2WI and patchy hyperintensity in the lesion	N.A	MRI: The arterial phase showed mild heterogeneous enhancement, in which patchy areas of significant enhancement were observed, the capsule was significantly enhanced, the degree of enhancement was reduced in the portal venous phase and delayed phase, and the signal was lower than that in the normal pancreatic parenchyma	N.A	Unclear demarcation from superior mesenteric vein	-

Using US, pancreatic PEComas typically appeared as low-echo, well-defined masses. Further investigation was usually conducted with CT or MRI. On non-enhanced CT, they were generally well-defined, round, homogeneous masses, with nearly all having a capsule. On MRI, most pancreatic PEComas appeared hypointense to the pancreas on T1WI and hyperintense on T2WI. After contrast enhancement, there was usually mild to moderate enhancement in the arterial phase, with reduced enhancement in the portal and delayed phases.

Comprehensive analysis of the imaging characteristics of pancreatic PEComa yielded the following: (1) lesions typically had a round morphology, only two of 17 cases having irregular shapes, possibly related to the nature and size of the lesions; (2) they originated from the pancreatic stroma with relatively independent internal components, an expansive growth pattern, and clearly distinguishable lesion boundaries, regardless of the presence of a capsule; and (3) the pancreatic duct was usually not involved. However, large lesions could compress the adjacent duct, causing varying degrees of duct dilation. Lesions with malignant features could invade the pancreatic duct, leading to its dilation. (4) For lesions in the pancreatic head and neck, the common bile duct might be dilated through a mechanism similar to that of the pancreatic duct. (5) Solid components were most common in pancreatic PEComa, and therefore the solid appearance on imaging. On plain CT scans, they were typically iso-density or low-density. On T1WI, they exhibited low signals; on T2WI, they mainly showed high signals, with T2WI providing better visualization of solid lesions than plain CT scans. Cystic components in pancreatic PEComa were typically due to necrotic changes. Larger lesions were more likely to undergo necrosis and other secondary changes. In some cases, they demonstrated hemorrhage and calcification, notable characteristics of PEComa. (6) Unlike hypovascular tumors such as pancreatic cancer, pancreatic PEComa had a relatively abundant blood supply. (7) The enhancement characteristics of PEComa depended on the lesion’s composition and size; cystic components showed no enhancement, while solid components exhibited varying degrees of enhancement. Small lesions typically had uniform enhancement, while larger lesions were more heterogeneous.

The imaging diagnosis of pancreatic PEComa, although challenging, can help to distinguish it from other common pancreatic tumors. (1) Neuroendocrine tumors, which are typically small and often benign, show greater enhancement than pancreatic PEComa. On EUS biopsy, they show islet cells that are IHC positive for Chromogranin A, Neuron Specific Enolase, and synaptophysin. They may be malignant with distant metastases [28]. (2) Solid pseudopapillary tumors of the pancreas typically occur at a younger age than pancreatic PEComa. They also have a higher incidence of hemorrhage, cystic changes, and calcification, leading to uneven density or signal within the lesion. Additionally, mild dilation of the pancreaticobiliary duct may be observed [29]. (3) Pancreatic cancer typically presents with spiculated unclear margins and varying degrees of invasion into adjacent tissues. The proximal pancreaticobiliary duct is often dilated, the distal pancreas may be atrophied, and peripheral lymph nodes or distant metastases are common [30].

Because only 2 of the 26 PEComa cases were definitively documented to be malignant, and the usual imaging appearance was consistent with a localized benign tumor, a more definitive preoperative diagnosis that might justify a conservative local ablative treatment could be considered as opposed the much more invasive and risky Whipple operation to treat a pancreatic cancer. The principal classification system to determine malignancy of PEComas of the uterus and other sites was the Folpe score. Folpe et al. [31] divided PEComas into three groups based on six indicators: benign, malignant potential undetermined, and malignant, with specific indicators as follows: tumor ≥ 5 cm, division count > 1/50 HPF, necrosis, invasive growth, high grade nucleus, and vascular invasion. If any of the above characteristics are not present, it is classified as benign; those with at least two characteristics are classified as malignant; If only one of the above histological features is present, the malignant potential is undetermined, such as the nucleus is pleomorphic, or the tumor is 5 cm ≥ without other aggressive features. These criteria have been validated in non-gynecologic site tumors.

In the absence of any Folpe classification worrisome features obtained by EUS-biopsy, and innocent appearing imaging characteristics, presently accepted techniques of EUS-guided intra-tumoral ablation could be considered. These include ethanol injection which has been successfully applied to pNETs and pancreatic cystic neoplasms (PCN). Moreover, EUS-guided radiofrequency ablation (RFA) has also been used on pNETs and PCNs as well as pancreatic adenocarcinomas. Finally, cryo-thermal ablation has been used citing a combination of the beneficial effects of RFA and cryotechnology [32, 33].

Conclusions

In summary, pancreatic PEComa is a rare stromal tumor, typically benign. We present such a case, analyzing the clinical history, imaging manifestations, histopathological findings, immunohistochemistry results, minimally invasive cytopathology and tumor ablative approaches, and prognosis. Due to their rarity and subtlety, these tumors often present challenges for clinicians in detection. This article examines pancreatic PEComa through its clinical, pathological, and imaging characteristics, this is intended to improve diagnostic accuracy for clinicians.

Author contributions

PPH contributed to manuscript preparation. KXC provided the figures. PPH, CFY, and YL were involved in data acquisition, analysis, or interpretation. JHY and YL revised the manuscript. All authors reviewed and approved the final version for publication.

Funding

The research was funded by Nanchong City School Science and Technology Strategic Cooperation Project (22SXQT 0294), Guang’an Science and Technology Bureau (2022zdxjh18) and Research and Development Program of North Sichuan Medical College (CBY23-QNA51).

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Consent for publication

The North Sichuan Medical College Ethics Review Committee waived the requirement for patients to sign the informed consent form.

Competing interests

The authors declare no competing interests.

Ethics approval

This study was approved by the Institutional Review Board (IRB) of North Sichuan Medical College Ethics Review Committee.