Eosinophilic Solid and Cystic Renal Cell Carcinoma (ESC-RCC) is a recently recognized, uncommon subtype of renal cell carcinoma, previously referred to as tuberous sclerosis complex-associated RCC. It is characterized by distinct histopathological and molecular features and predominantly affects middle-aged women. Clinically, ESC-RCC typically presents as a well-circumscribed renal mass with a solid and cystic architectural pattern. Unlike other RCC subtypes, ESC-RCC generally follows an indolent clinical course and is associated with a favorable prognosis. However, metastasis occurs in fewer than 10% of cases.

A 58-year-old male with medical history of hypertension and previous coronary artery disease managed with stent placement, manifested with intermittent gross hematuria for several weeks and left flank soreness persisting for months. Renal sonography showed right renal tumor of 7cm in size. Abdominal and pelvic CT demonstrated a 9.7cm lobulated, heterogeneous, hyperdense mass in the right renal upper pole with thrombus formation in the right renal vein and suspected invasion of the perirenal fat and pelvicalyceal system. The patient received 3 cycles of immunotherapy with pembrolizumab in combination with targeted therapy using sunitinib. Restaging CT showed disease progression with an increase in size of necrotic right renal mass. Hence, open right radical nephrectomy with renal vein thrombectomy were performed.

Pathological analysis revealed eosinophilic solid and cystic RCC with rhabdoid features, tumor necrosis and lymphovascular invasion (pT3aN0M0). However, restaging CT performed three months postoperatively identified multiple newly developed liver nodules, suggestive of metastatic progression(pT3aN0M1). The patient is currently undergoing treatment with Lenvatinib.

This rare variant of eosinophilic solid and cystic renal cell carcinoma (ESC-RCC) exhibits a poor prognosis and a high metastatic rate, particularly in tumors with adverse prognostic features.