Nasrallah Oussama G, AlJardali Baraa, El Asmar Jose M, El Kasti Abdallah, El Hajj Albert
Division of Urology, Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
Ann Med Surg (Lond). 2024 Aug 14;86(10):6198-6202. doi: 10.1097/MS9.0000000000002479. eCollection 2024 Oct.
Renal cell carcinoma (RCC) is the most common primary renal malignancy in patients between the ages of 50 and 70. A rare described variant of RCC is transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3) rearranged RCC. Osseous metaplasia, which refers to the occurrence of normal bone tissue in soft tissue, has been observed in all subtypes of renal cell carcinoma (RCC); however, only three previous case reports have documented the occurrence of osseous metaplasia in TFE3-rearranged RCC.
We present a case of a 65-year-old woman presenting with an incidentally discovered calcified Bi-lobed renal mass detected on bone densitometry composed of a calcified thick-walled cyst measuring 7×6.5×6.5 cm showing intraluminal densities and heterogeneous content, and a lobulated partially exophytic renal mass measuring 4.5×5.5×4.5 cm. The patient underwent robotic-assisted radical nephrectomy confirming the diagnosis of RCC with osseous metaplasia extending into the pelvic calyces and renal sinus fat implicating a pathological stage of T3a.
TFE3-rearranged RCCs represent a rare sub-classification in adult RCCs. It may be associated with unfavorable prognosis and aggressive patterns of disease in the presence of osseous metaplasia.
This is the first case in the literature of TFE3-rearranged RCC with osseous metaplasia on bone mass densitometry scan and the fourth case of TFE3-rearranged RCC with osseous metaplasia. The patient is to be treated as a high-risk patient and to be monitored closely for recurrence of malignancy, as indicated in the EAU guidelines.
肾细胞癌（RCC）是50至70岁患者中最常见的原发性肾脏恶性肿瘤。一种罕见的肾细胞癌变异型是免疫球蛋白重链增强子3（TFE3）重排的肾细胞癌。骨化生是指在软组织中出现正常骨组织，在肾细胞癌（RCC）的所有亚型中均有观察到；然而，之前仅有三篇病例报告记录了TFE3重排的肾细胞癌中骨化生的发生情况。
我们报告一例65岁女性病例，该患者在骨密度测量时偶然发现双侧钙化肾肿块。肿块由一个7×6.5×6.5厘米的钙化厚壁囊肿组成，囊腔内有密度影且内容物不均匀，还有一个4.5×5.5×4.5厘米的分叶状部分外生性肾肿块。患者接受了机器人辅助根治性肾切除术，确诊为肾细胞癌伴骨化生，骨化生延伸至肾盂盏和肾窦脂肪，提示病理分期为T3a。
TFE3重排的肾细胞癌是成人肾细胞癌中一种罕见的亚分类。在存在骨化生的情况下，它可能与不良预后和侵袭性疾病模式相关。
这是文献中首例在骨密度扫描中发现骨化生的TFE3重排肾细胞癌病例，也是第四例TFE3重排肾细胞癌伴骨化生病例。根据欧洲泌尿外科学会（EAU）指南，该患者应被视为高危患者，并密切监测恶性肿瘤复发情况。
