Renal PEComa in a young male: A case report and insights from the literature

Abstract

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms, commonly found in the uterus and retroperitoneum. Renal PEComas are exceedingly rare, often posing diagnostic challenges due to their resemblance to renal cell carcinoma (RCC) on imaging. We present the case of an 18-year-old male who presented with non-specific symptoms of fever, chills, and shivering. Imaging revealed a renal mass, initially suspected to be RCC. However, following a right radical nephrectomy, histopathological examination confirmed the diagnosis of malignant PEComa. This case highlights the rarity of renal PEComa and underscores the importance of early diagnosis and appropriate surgical management to prevent complications.

1 Introduction

Perivascular epithelioid cell tumors (PEComas) are a rare group of mesenchymal neoplasms characterized by perivascular cells, with the most common sites being the uterus and retroperitoneum. . PEComas encompass a diverse spectrum of tumors, including angiomyolipoma, clear cell “sugar” tumor of the lung, lymphangioleiomyomatosis, and several atypical tumors located in the visceral organs, abdomen, and soft tissues/bones, such as clear cell tumors. . These neoplasms consist of epithelioid or spindle cells, identifiable through histological and immunohistochemical analysis. . Imaging modalities are often inconclusive, making definitive diagnosis challenging and typically reliant on post-surgical findings. While the majority of PEComas are benign and predominantly affect women, , renal PEComas are exceptionally rare. This paper presents a case of renal PEComa, incidentally detected in an asymptomatic young male, and includes a review of previously reported cases due to its rarity.

2 Case report

An 18-year-old male patient presented to our hospital with new onset complaints of fever, chills, and shivering. He had no history of hereditary or infectious diseases, nor did he consume alcohol or smoke. During the physical examination, a mass was detected in the right kidney. Blood analysis results were as follows: hemoglobin 131 g/L, platelet count 294 x 10³/μL, leukocyte count 8.33 x 10³/μL, erythrocyte count 5.02 x 10⁶/μL, and a normal coagulogram. Biochemical analysis revealed glucose levels of 102 mg/dL, creatinine 0.7 mg/dL, and C-reactive protein 1.3 mg/L.

Seven years prior, a contrast-enhanced computed tomography (CT) scan had revealed the presence of an angiomyolipoma nodule in the lateral region of the right kidney, located in the middle third of the cortical layer. Recent CT and magnetic resonance imaging (MRI) identified several angiomyolipomas, the largest measuring 15× 14 mm, on both kidneys. Additionally, a solid mass measuring 38 x 36 × 35 mm was detected in the middle portion of the right kidney ( Fig. 1 ). Contrast-enhanced imaging showed that the tumor appeared hypovascular compared to the renal parenchyma, with no detectable “washout” effect. MRI images demonstrated restricted diffusion within the tumor, along with fatty tissue presence, leading to a preliminary diagnosis of renal cell carcinoma (RCC). The patient’s symptoms initially suggested a renal abscess, prompting a shift from biopsy to curative treatment.

The patient was subsequently undewent a right radical nephrectomy. Histological examination of the specimen revealed capsule invasion, infiltrative growth pattern, high nuclear grade and cellularity, vascular invasion, necrosis, and high mitotic rate, leading to a diagnosis of malignant PEComa ( Figs. 2 and 3 ).