Perivascular epithelioid cell tumor (PEComa) of the kidney: an overview of its management and outcomes

Case report: Urachal perivascular epithelioid cell tumor

Background

Urachal tumors are rare in clinical practice, among which urachal adenocarcinoma is the most common. In this study, we report a rare case of urachal perivascular epithelioid cell tumor to improve our understanding of the disease.

Case presentation

A 26-year-old male patient was hospitalized for lower abdominal pain. The US showed a hypoechoic mass measuring 26mm × 18mm in the superior aspect of the bladder. MRI showed an irregular mass located anterior to the bladder roof, near the midline. The tumor exhibited hypointense on T1WI and heterogeneous hyperintense on T2WI. Additionally, contrast-enhanced T1-weighted imaging revealed obvious ring enhancement of the tumor. The patient underwent surgical resection of the urachal tumor, with subsequent pathological examination revealing a diagnosis of urachal PEComa. Following surgery, the patient underwent regular follow-up assessments, with no evidence of recurrence or metastasis observed after three and a half years.

Conclusions

Urachal PEComa is a rare mesenchymal tumor that presents challenges in diagnosis through imaging and clinical symptoms. Definitive diagnosis relies on pathological and immunohistochemical analysis. Due to the rarity of urachal PEComa, prognosis assessment necessitates long-term follow-up and evaluation of more cases.

Sclerosing epithelioid fibrosarcoma of the kidney

A woman in her 20s presented with headache and back pain and was found to have a left renal mass with bony metastases. She underwent nephrectomy, and on histopathology was initially diagnosed with stage 4 clear cell sarcoma of the kidney. She underwent palliative radiation and chemotherapy; however, the disease progressed and she came to our centre. We started her on second-line chemotherapy and submitted her tissue blocks for review. Due to her age and lack of sclerotic stroma in the tissue, we had our doubts about the diagnosis and hence, tissue sample was submitted for next-generation sequencing (NGS). NGS detected an EWSR1::CREBL1 fusion, clinching the final diagnosis of sclerosing epithelioid fibrosarcoma of the kidney, a singular diagnosis rarely reported in the literature. Currently, the patient is post her third line of chemotherapy, is on maintenance, and is doing well and has resumed her daily activities.

Laparoscopic radical nephroureterectomy in the oblique supine lithotomy integrative position for rare renal malignant perivascular epithelioid cell tumor with renal vein cancerous thrombosis: A case report and literature review

RATIONALE

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor that arises from perivascular epithelioid cells and can differentiate into melanocytes and smooth muscle cells. Malignant renal perivascular epithelioid cell tumor is extremely rare. Due to the lack of specific clinical manifestations and imaging features, diagnosing PEComa depends on postoperative pathology and immunohistochemistry. Surgery is the primary treatment for malignant PEComa because the efficacy of radiotherapy and chemotherapy is uncertain. There is still a lack of unified diagnostic criteria and treatment guidelines for renal malignant PEComa, especially with vascular invasion. Hence, the treatment experience depends on a small number of cases reported worldwide.

PATIENT CONCERNS

A 68-year-old woman was admitted to our hospital due to intermittent hematuria for over 8 months. The color Doppler ultrasound and computed tomography scan revealed a mass in the lower middle part of the left kidney.

DIAGNOSIS

Rare renal malignant perivascular epithelioid cell tumor with renal vein cancerous thrombosis.

INTERVENTIONS

A laparoscopic radical left nephroureterectomy in the oblique supine lithotomy position was performed.

OUTCOMES

The operation process went smoothly, and no pulmonary embolism occurred after the operation. The final pathological diagnosis was a renal malignant perivascular epithelioid cell tumor. After a 12-month follow-up, no recurrence or metastasis was found.

LESSONS

Renal malignant PEComa is an extremely rare mesenchymal tumor diagnosed mainly based on pathology. Surgery is currently the effective treatment for malignant PEComa. For the surgical treatment of malignant renal PEComa with vascular invasion, laparoscopic radical nephroureterectomy in the oblique supine lithotomy integrative position has many benefits, as exemplified by our current case.

Natural History and Treatment Strategies of Advanced PEComas: A Systematic Review

Simple Summary

In this article, we review the clinical features of advanced PEComas and show the diversity of reported data among authors, emphasizing the heterogeneity of molecular characterization and treatment strategy. Based on clinical data collected from 124 case reports, metastatic disease at diagnosis and a grouped version of the Bleeker’s risk category were the only factors significantly associated with death. Due to a significant number of missing data or short follow-ups, results regarding prognostic factors should, however, be interpreted with caution.

Abstract

PEComas is a family of rare mesenchymal tumors. This systematic review aims to better understand the natural history of advanced PEComas. After a search on the PubMed database and main oncology meeting libraries according to the PRISMA guidelines, 88 articles reported in the English literature were included. Data on clinical and histological features, treatments and outcomes were collected. To identify risk factors, univariate and multivariate analyses were performed. Seven cohorts of patients and 124 individual patients were identified. Focusing on case reports, most patients were metastatic, and the median overall survival (OS) of the entire cohort was 60 months (95%CI 33; NA). Risk factors significantly associated with OS in the multivariate analysis were the presence of metastasis at diagnosis (HR: 2.59, 95%CI 1.06; 6.33, p = 0.036) and the grouped-Bleeker’s risk category (HR: 4.66; 95%CI 1.07; 20.19; p = 0.039). In the metastatic population, only the presence of lymph node metastasis was associated with OS (HR: 3.11; 95%CI 1.13; 8.60, p < 0.05). Due to a lack of events, it was not possible to conclude on other factors. This review of the literature highlights the heterogeneity of literature data and shows the great diversity of clinical management strategies.

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.