Perivascular epithelioid cell tumor: the first malignant case report in the pancreas. Appl Immunohistochem Mol Morphol. 2013;21:e1-e4. [PMID: 23591015 DOI: 10.1097/pai.0b013e3182392bb6]

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

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

Perivascular Epithelioid Cell Tumor (PEComa) of the Pancreas in a Patient with Ulcerative Colitis: A Case Report and Review of the Literature

Perivascular epithelioid cell tumors (PEComas) are mesenchymal tumors of peculiar cells that are focally associated with blood vessels, and generally have a distinctive bi-phenotypic expression of both smooth muscle and melanocytic markers. There are several entities in the PEComa family, including tumors that arise in the soft tissues and viscera. Frequently affected organs include the lungs (sugar tumors), uterus, broad ligament, colon, small bowel, liver, and pancreas. Ulcerative colitis (UC) has been associated with the development of tumors, especially colorectal and hepatobiliary carcinomas. Rare cases of UC have been reported in the PEComa family of tumors, but none in the pancreas. Here, we present a case study of a 27-year-old female patient with a history of UC who developed PEComa of the pancreas, a unique association that has not been previously reported. We also review reported cases of PEComas in the pancreas, as well as PEComas at all anatomic sites associated with UC.

Perivascular Epithelial Cell Tumor of the Pancreas Diagnosed Preoperatively by Endoscopic Ultrasound-guided Fine-needle Aspiration

We herein report a 49-year-old woman with a perivascular epithelial cell tumor (PEComa) of the pancreas. Imaging studies demonstrated a relatively well-demarcated mass, measuring approximately 40 mm in diameter, located in the pancreatic tail. It was heterogeneously enhanced almost to the same degree as the surrounding pancreatic tissue in both the arterial and portal venous phases. We performed endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) using the Acquire^® 22-gauge needle and preoperatively obtained a definitive diagnosis with a sufficient sample. Clinicians should consider pancreatic PEComa in their differential diagnosis of patients with a pancreatic mass.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Rare Tumors and Lesions of the Pancreas

There are a few entities that account for most solid and cystic masses of the pancreas. The pancreas harbors a wide array of diseases, including adenocarcinoma, and its variants, such as anaplastic and adenosquamous carcinoma. Other neoplasms include acinar cell carcinoma, solid pseudopapillary tumor, and sarcomas. Benign lesions include hamartomas, hemangiomas, lymphangioma, and plasmacytoma. Isolated metastases include renal cell carcinoma, melanoma, and other carcinomas. Benign inflammatory conditions, such as autoimmune pancreatitis and groove pancreatitis can also mimic solid neoplasms of the pancreas.

Perivascular epithelial cell tumor (PEComa) of the pancreas: A case report and review of literature

RATIONALE

Perivascular epithelial cell tumors (PEComas) of the pancreas are rare mesenchymal tumors and, to our knowledge, only 20 cases have been reported to date.

PATIENT CONCERNS

We report a 43-year-old female who presented with upper abdominal pain for 1 year. She underwent an exploratory laparotomy at a local hospital, which failed to resect the tumor. Five months later, she came to the Chinese National Cancer Center for surgery. Preoperative imaging revealed an 11.5-cm-sized mass located in the head of the pancreas. At the microscopic level, the tumor was composed of epithelioid and spindle cells possessing clear to focally granular eosinophilic cytoplasm, which grew in a nested and alveolar pattern around blood vessels. The tumor cells showed immunoreactivity for human melanoma black 45 (HMB-45), but did not express epithelial or endocrine markers.

DIAGNOSES

Pancreatic PEComa.

INTERVENTIONS

Pancreaticoduodenectomy, partial hepatectomy, and vascular replacement were performed. After the surgery, the patient received 4 cycles of chemotherapy.

OUTCOMES

The patient is free of recurrence and metastasis 1.5 years after surgical resection.

LESSONS

PEComa should be recognized as a preoperative differential diagnosis of pancreatic tumors. For treatment, removal of the tumor should be attempted, and in the case of tumors with malignant tendencies, the addition of chemotherapy should be considered.

Perivascular epithelial cell tumor (PEComa) of the pancreas: a case report and review of previous literatures

Perivascular epithelial cell tumors (PEComas), firstly described by Bonetti in 1992, are a family of mesenchymal tumor composed of perivascular epithelioid cells having epithelioid or spindle morphology and exhibiting melanocytic and myogenic immunoreactivities. We herein described a 61-year-old woman who presented with epigastric pain. Preoperative imaging studies showed that 7-cm-sized mass was located in pancreatic head and body, and pancreaticoduodenectomy was performed. Histological findings showed that the tumor was composed of clear epithelioid cells with abundant glycogen granules, which grew in a nested and alveolar pattern around blood vessels. The tumor cells showed immunoreactivities for HMB-45 but did not express epithelial or endocrine markers. These histological features indicated those of PEComa. This report underlines that we should recognize PEComa as a preoperative differential diagnosis of pancreatic tumors.

Pancreatic perivascular epithelioid cell tumor: A case report with clinicopathological features and a literature review

Perivascular epithelioid cell tumor (PEComa) of the pancreas is an unusual tumor deriving from mesenchyma. This paper described a case of pancreatic PEComa, which was initially suspected as neuroendocrine carcinoma by biopsy, and therefore surgical treatment was recommended due to undetermined diagnosis. Examination of the surgical specimen under a microscope showed that the tumor cell’s morphology was epithelioid or spindle-shaped, and ranged in a nested pattern. Additionally, these cells had a large extent of acidophilic cytoplasm, no mitotic figures, and expressed HMB-45, melan-p, and smooth muscle actin immunohistochemically. Pathological examination indicated that PEComa originated from the pancreas, but symptoms related to tuberous sclerosis were absent. Since PEComa is extremely rare in the pancreas, it is likely to be ignored in differential diagnosis. In conclusion, our article highlighted the clinicopathological features of PEComa, and we conducted a literature review focusing on PEComa so as to deepen the understanding of this tumor type.

Laparoscopic excision of infra-renal PEComa

Perivascular epitheloid cell tumors (PEComas) are rare tumors of malignant potential. There is no normal cell variant to these cells. The family is large and includes angiomyolipoma, clear cell “sugar” tumor amongst others. Imaging modalities are not very diagnostic. The diagnosis hence is often postoperative. A 55-year old female presented to us with ultrasonographic diagnosis of solid mass in the right infrarenal region. Contrast-enhanced computerized sonography (CECT) suggested paraganglioma or a soft tissue retroperitoneal tumor. Laparoscopic excision was successful. The rarity of this pathology and laparoscopic modality of excision prompted us to publish this report.

Perivascular epitheloid cell tumor (PEComa) mimicking retroperitoneal liposarcoma

PEComas are a collection of generally rare tumors, defined by the World Health Organization as ‘mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epitheloid cells’. We describe the case of retroperitoneal PEComa with a liposarcoma-like appearance on cross-sectional imaging, but distinctive immunohistochemistry revealing the correct diagnosis.