Renal cell carcinoma arising in a long pre‐existing angiomyolipoma

Abstract

Angiomyolipoma (AML) is a mixed mesenchymal tumor belonging to the family of perivascular epithelioid cell tumors. Concurrent development of AML and adult renal cell carcinoma (RCC) is very rare. Herein is presented a unique case in which RCC arose within a previously detected AML tumor mass. A 40-year-old woman had been diagnosed with AML of the right kidney. Fifteen years later, during a regular radiographic examination, a new lesion was detected at the lower pole of the right kidney adjacent to the previously described AML. Because RCC was clinically suspected, the patient underwent right nephrectomy. Macroscopically, the tumor had a yellowish, transparent, fatty area and an opaque yellowish area with cystic features. Microscopically, the former tumor, consisting of an admixture of mature adipose tissue with smooth muscle and vascular tissue, was diagnosed as AML. The latter tumor was diagnosed as RCC (clear cell type). RCC was not completely enclosed within the AML, but overlapped it. No fibrous capsule was found between these tumors. Although this situation is very rare, from a clinical and pathological point of view it is important to consider the possibility that RCC might arise within AML. The relationship between the two lesions is discussed with a review of the literature.

Occult Renal Cell Carcinoma of Eosinophilic Morphology Detected within Renal Angiomyolipoma Mass in a Patient with Tuberous Sclerosis Complex

“…[12] The coexistence of RCC and renal AML within same tumor masses, namely collision tumor, is very rare, and about six cases have been reported. [3] Here, we present a case of a young male with TSC and multiple AMLs, containing RCC with eosinophilic morphology.…”

“…Inomoto et al . [3] had reported one case of RCC originated in a previously existing AML and considered that RCC arose in the AML from the clinical and pathological point of view. However, other researchers suggested that AML and RCC were coincidentally present in the same tumor mass.…”

Coexisting Hybrid Malignancy in a Solitary Sporadic Solid Benign Renal Mass: Implications for Treating Patients Following Renal Biopsy

“…Although isolated case reports of AMLs coexisting with a malignancy do exist, such lesions appear to be exceedingly rare. 20 …”

Renal angiomyolipoma with renal vein invasion

“…Renal angiomyolipoma is usually a benign lesion, it can be rarely associated to renal adenocarcinoma (4,5) and to tuberous sclerosis. The histology shows mature adipose tissue, smooth muscle, and thick-walled blood vessels.…”