Perivascular epithelioid cell tumor (PEComa) with perirenal manifestation

Perirenal Perivascular Epithelioid Cell Tumor (PEcoma) with Pulmonary Micro Invasive Adenocarcinoma: A Case Report and Literature Review

Perivascular epithelioid cell tumor (PEComa) is a rare type of mesenchymal neoplasm, which occurs most commonly in uterus and gastrointestinal tract. PEComa with perirenal manifestation is an extremely rare entity. To the best of our knowledge, only four cases have been reported up to now. In this case, we reported a patient with both a pulmonary mass and a perirenal mass. Two resections were performed successively and postoperative pathology suggested pulmonary micro invasive adenocarcinoma (MIA) and perirenal PEComa. This is the first case of perirenal PEComa with pulmonary MIA. Combining the present case and prior literature, we summarized the crucial role of immunohistochemistry in the diagnosis and consider that complete operation might be conducive to patients with perirenal PEComa that presents a benign phenotype, regardless of complications with other tumors.

Retroperitoneal perivascular epithelioid cell tumours: A case report and review of literature

BACKGROUND

The perivascular epithelioid cell tumour (PEComa) family of tumours mainly includes renal and hepatic angiomyolipomas, pulmonary lymphangioleiomyomatosis and clear cell “sugar” tumour of the lung. Several uncommon tumours with similar morphological and immunophenotypical characteristics arising at a variety of sites (abdominal cavity, digestive tract, retroperitoneum, skin, soft tissue and bones) are also included in the PEComa family and are referred to as PEComas not otherwise specified.

CASE SUMMARY

We present a 37-year-old female patient who underwent resection of an 8.5 cm × 8 cm × 4 cm retroperitoneal tumour, which eventually was diagnosed as PEComa of uncertain biological behaviour. Three years after the operation, the patient remains without any evidence of recurrence. A search was performed in the Medline and EMBASE databases for articles published between 1996 and 2018, and we identified 31 articles related to retroperitoneal and perinephric PEComas. We focused on sex, age, maximum dimension, histological and immunohistochemical characteristics of the tumour, follow-up and long-term outcome. Thirty-four retroperitoneal (including the present one) and ten perinephric PEComas were identified, carrying a malignant potential rate of 44% and 60%, respectively. Nearly half of the potentially malignant PEComas presented with or developed metastases during the course of the disease.

CONCLUSION

Retroperitoneal PEComas are not as indolent as they are supposed to be. Radical surgical resection constitutes the treatment of choice for localized disease, while mammalian target of the rapamycin (mTOR) inhibitors constitute the most promising therapy for disseminated disease. The role of mTOR inhibitors as adjuvant or neoadjuvant therapies needs to be evaluated in the future.

Perirenal PEComa: Computed Tomography Findings and Differential Diagnosis

The World Health Organization defines perivascular epithelioid cell tumors (PEComas) as mesenchymal tumors and tumor-like conditions composed of epithelioid cells with a perivascular distribution. These tumors may show benign or malignant histology and/or biological behavior. However, the pathological features of malignancy may not correlate with biologic aggressiveness, and the criteria for malignancy are not clearly defined. Abdominopelvic PEComas are very rare and have been reported in various locations, including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. Cross-sectional imaging techniques, including computed tomography (CT) may play an important role in the accurate detection and characterization of these tumors. We present the third case of an extremely rare PEComa with perirenal location, discuss CT findings and differential diagnosis.

Perivascular epithelioid cell tumor of the ileum presenting as diverticulitis

Perivascular epithelioid cell tumors (PEComas) are a group of rare mesenchymal neoplasms. Gastrointestinal PEComas are exceptionally rare, there being only a few case reports in the literature involving the colon and small intestine. Nearly all PEComas show immunoreactivity for both melanocytic (HMB45 and/or Melan-A) and smooth muscle (actin and/or desmin) markers. A 36-year-old male was admitted to the hospital with acut- abdomen. At laparatomy, a nodular mass protruding from the ileum which clinically simulated a diverticulitis was noticed. Gross examination of the specimen revealed a 2 × 1,5 × 1 cm secondarily ulcerated, solid, nodular, gray white tumor mass in the ileal wall. Histologically, tumor cells were composed of nests of round-polygonal epithelioid cells with abundant clear to slightly eosinophilic granular cytoplasm and round vesicular nuclei. The nests were separated by thin fibrovascular septa. Minimal necrosis and low mitotic activity were noticed in the tumor. Immunohistochemically, tumor cells were positive for SMA, HMB45, and Melan-A and negative for CD10, RCC, CD45, CD117, CD34, EMA, and Desmin. Diagnosis was PEComa of the ileum. We report the case of ileal PEComa to remind the unusual presentation (diverticulitis) of these tumors, besides rarity and diagnostic difficulties.

Perivascular epithelioid cell tumour (PEComa) of the inferior vena cava presenting as an adrenal mass

A 54-year-old woman had a mass located in the right suprarenal area. On imaging, this mass appeared to be infiltrating the inferior vena cava (IVC). Exploratory laparotomy was undertaken and excision of the tumour was done with the sleeve of the involved IVC. The mass turned out to be a perivascular epithelioid cell tumour (PEComa) on histopathological examination. This report describes previously reported cases of PEComa in brief and highlights the problems associated with the management of this tumour.

Perivascular epithelioid cell tumor (PEComa) of the uterus: an outcome-based clinicopathologic analysis of 41 reported cases

The uterus and retroperitoneum have emerged as the most frequently reported anatomic sites of origin of perivascular epithelioid cell tumors (PEComas), a poorly defined neoplasm that is characterized by varying amounts of spindle and epithelioid cells with clear to eosinophilic cytoplasm that display immunoreactivity for melanocytic markers, most frequently HMB-45. Published reports on 41 previously reported uterine PEComas are reviewed in this report. Of these 41 cases, 31 originating in the corpus and for which there was adequate follow-up information (or clinical malignancy) were categorized into 2 groups: (1) a malignant group that was comprised of cases associated with patient death of disease and/or clinical malignancy as evidenced by local and/or distant extension outside of the uterus (n=13, group 1) and (2) a "nonmalignant" group of cases in which neither of the above features were present (n=18, group 2). Groups 1 and 2 did not significantly differ regarding duration of follow-up (25 mo vs. 24.3 mo, respectively, P=0.9) or patient age (45.61 y vs. 43.46 y, respectively, P=0.7). Five of the group 1 patients experienced distant (extra-abdominal) metastases. The group 1 tumors were significantly larger than the group 2 tumors (averages 9.6 cm vs. 4.67 cm respectively, P=0.04); however, there were no size thresholds that, in of themselves, reliably classified 75% or more of the cases in both groups. Coagulative necrosis was highly associated with group 1, being present in 82% of cases as compared with only 11.8% of group 2 cases (P=0.0002). Eighty-eight percent of the group 2 cases had a mitotic rate of <or=1/10 high power fields (HPF) as compared with 40% of group 1 cases (P=0.01). However, the absence of mitotic activity did not rule out malignancy, as 2 of the group 1 cases lacked mitotic activity and displayed metastases. Twenty-five percent, 49%, 56%, 73%, and 100% of tested cases displayed immunoreactivity for CD10, desmin, vimentin, smooth muscle actin, and caldesmon, respectively. PEComas are tumors of uncertain histogenesis and malignant potential that seem to display some morphologic and immunophenotypic overlap with smooth muscle neoplasia. A mitotic count of >1/10 HPF and/or coagulative necrosis are features that, if present, raise the definite potential for aggressive behavior.

Neoplasms of the Perivascular Epithelioid Cell Involving the Abdomen and the Pelvis

Neoplasms of the perivascular epithelioid cell (PEComas) represent a recently described heterogeneous group of mesenchymal tumors characterized by the presence of specific histological, immunohistochemical, and ultrastructural findings. The PEComas encompass a family of neoplasms that include angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. The PEComas demonstrate a wide spectrum of clinicobiological behavior and imaging findings. Perivascular epithelioid cell, as the name implies, is a unique cell that is characterized by perivascular distribution and epithelioid morphology. Perivascular epithelioid cell consistently shows immunoreactivity to melanocytic and smooth muscle markers including HMB-45 and actin. Abdominopelvic PEComas are found at a variety of somatic and visceral locations including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. A subset of patients with abdominopelvic PEComas manifests tuberous sclerosis complex. In this paper, we review the histological spectrum and discuss the imaging findings of the PEComas that involve the abdomen and pelvis.

Comparative genomic hybridization study of perivascular epithelioid cell tumor: molecular genetic evidence of perivascular epithelioid cell tumor as a distinctive neoplasm

Perivascular epithelioid cell tumor (PEComa) is a neoplasm composed chiefly of HMB-45-positive epithelioid cells with clear to granular cytoplasm and a perivascular distribution. Such tumors have been reported in different organs under a variety of designations. The cytogenetic features of these neoplasms have not been well studied. We collected 9 tumors (5 of kidney, 1 of prostate, 1 of urinary bladder, 1 of the pelvic cavity soft tissue, and 1 of uterus) from 8 patients, including one patient with tuberous sclerosis complex. The paraffin blocks of tumor tissue were submitted for comparative genomic hybridization analyses. Gross chromosomal aberrances were observed in all cases. The frequent imbalances were losses on chromosome 19 (8 cases), 16p (6 cases), 17p (6 cases), 1p (5 cases), and 18p (4 cases) and gains on chromosome X (6 cases), 12q (6 cases), 3q (5 cases), 5 (4 cases), and 2q (4 cases). The frequent deletion of 16p in which TSC2 gene is located indicates the oncogenetic relationship of PEComas with angiomyolipoma as a TSC2-linked neoplasm. From a molecular genetic perspective, the recurrent chromosomal alterations in both renal and extrarenal tumors further support the concept of PEComa as a distinctive tumor entity regardless of anatomic location.

Multimodal treatment using surgery, radiotherapy, and chemotherapy in a patient with a perivascular epithelioid cell tumor of the uterus

Perivascular epithelioid tumor (PEComa), a recently defined tumor, is a very rare disease affecting various organs, most often the uterus. This tumor displays a variety of histologic and clinical features and at this point is regarded as a tumor with uncertain malignant potential. A 9-year-old girl with abdominal pain and vaginal spotting was diagnosed with PEComa of the uterus with metastasis. She received chemotherapy comprising vincristine, ifosfamide, and doxorubicin, as well as radiotherapy after surgery. After this multimodal treatment, there was no evidence of recurrence or further metastasis. She remains disease-free 1.5 years after her initial diagnosis. PEComa of the uterus displaying malignant characteristics may have a more favorable response to more aggressive therapy.