Saliba Thomas, Rotzinger David, Vietti-Violi Naïk, Avola Emanuele
Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
Radiol Case Rep. 2025 Jun 24;20(9):4561-4566. doi: 10.1016/j.radcr.2025.06.009. eCollection 2025 Sep.
Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms with an incidence of approximately 0.3 per million. They exhibit histological and immunohistochemical features that overlap with angiomyolipomas and clear cell tumors. PEComas predominantly affect women and are either classified as being linked to tuberous sclerosis or are classified as PEComas-Not Otherwise Specified which means that their origin is not linked to tuberous sclerosis. They often arise from the genitourinary tract. The malignant potential of these tumors is determined by factors such as size (>5 cm), mitotic activity, necrosis, and vascular invasion. Treatment involves resection and mTOR inhibitors. Standardized treatment protocols are lacking due to rarity of the pathology, so each occurrence is considered on a case-by-case basis. A 69-year-old woman with dyspnea underwent CT imaging, revealing a large renal mass, a liver lesion, lung nodules, enlarged hilar lymph nodes, and a pulmonary embolism. Subsequent FDG-PET-CT confirmed FDG-avid lesions, with uptake of the pulmonary emboli suggesting their malignant origin. A subsequent liver biopsy diagnosed a malignant PEComa. MRI demonstrated T2 hyperintensity, restricted diffusion and postcontrast enhancement. Treatment with Everolimus resulted in a partial response of all lesions on 3-month follow-up imaging. PEComas were first recognized by the World Health Organization in 2002 and often present with nonspecific symptoms. They may manifest with metastatic disease at the time of diagnosis. This case highlights metastatic pulmonary embolism as an initial presentation. PEComas pose diagnostic challenges due to their nonspecific imaging findings and varied presentations. This case underscores their potential for aggressive behavior and the role of mTOR inhibitors. Despite successful treatment, the prognosis remains variable, necessitating multidisciplinary management and long-term surveillance. Early biopsy and molecular profiling are critical for optimizing outcomes. With this case report, we hope to bring attention to the possibility of pulmonary emboli being of metastatic origin when found in the context of a pre-existent oncological disease.
血管周上皮样细胞肿瘤（PEComas）是一种罕见的间叶性肿瘤，发病率约为百万分之0.3。它们具有与血管平滑肌脂肪瘤和透明细胞瘤重叠的组织学和免疫组化特征。PEComas主要影响女性，要么被归类为与结节性硬化症相关，要么被归类为未另行指定的PEComas，这意味着它们的起源与结节性硬化症无关。它们常起源于泌尿生殖道。这些肿瘤的恶性潜能由大小（>5cm）、有丝分裂活性、坏死和血管侵犯等因素决定。治疗包括手术切除和mTOR抑制剂。由于该病理罕见，缺乏标准化的治疗方案，因此每个病例都需逐案考虑。一名69岁呼吸困难的女性接受了CT成像，显示有一个大的肾肿块、一个肝脏病变、肺结节、肺门淋巴结肿大和肺栓塞。随后的FDG-PET-CT证实了FDG摄取阳性的病变，肺栓塞部位的摄取提示其为恶性起源。随后的肝脏活检诊断为恶性PEComa。MRI显示T2高信号、扩散受限和增强后强化。依维莫司治疗在3个月的随访成像中使所有病变出现部分缓解。PEComas于2002年首次被世界卫生组织认可，通常表现为非特异性症状。它们在诊断时可能伴有转移性疾病。本病例突出了转移性肺栓塞作为初始表现。由于其非特异性的影像学表现和多样的临床表现，PEComas带来了诊断挑战。本病例强调了它们具有侵袭性行为的可能性以及mTOR抑制剂的作用。尽管治疗成功，但预后仍然不一，需要多学科管理和长期监测。早期活检和分子分析对于优化治疗结果至关重要。通过本病例报告，我们希望引起人们对在存在肿瘤性疾病背景下发现的肺栓塞为转移起源可能性的关注。
