title: Malignant transformation of renal angiomyolipoma: a case report.
abstract: We report a case of renal angiomyolipoma (AML) with malignant transformation. A 28-year-old woman developed large bilateral renal masses 5 months before admission to our hospital. She was diagnosed with tuberous sclerosis when she was 4 years old. Total nephrectomy of the left kidney was performed, but she died during the operation. Although the focal region of the resected tumor had the appearance of a classic AML, most of the lesion showed a diffuse proliferation of atypical epithelioid cells resembling that in renal cell carcinoma. The epithelioid cells had extremely pleomorphic and hyperchromatic nuclei with frequent mitotic figures, including atypical forms. Immunohistochemical analysis revealed that the atypical epithelioid cells and the typical AML lesions were both positive for HMB-45 but that the former were negative for epithelial and myogenic markers. The smooth muscle cells and thick-walled vessels were focally positive for muscle-specific actins. Furthermore, the atypical epithelioid cells were immunoreactive for p53, whereas the foci of the typical AML were negative. Examination of the microdissected paraffin-embedded tissues revealed p53 mutations in the malignant epithelioid areas in AML but not in the renal parenchyma or typical AML areas. In this case it is proposed that p53 mutation may play an important role in malignant transformation of renal AML.
authors.affiliation: Department of Anatomic Pathology, (Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
authors.forename: Sadafumi
authors.initials: S
authors.lastname: Tamiya
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Nakahara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Matsuoka
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
mesh_terms: D000199:Actins / Q000032:analysis; D000328:Adult; D018207:Angiomyolipoma / Q000737:chemistry / Q000473:pathology*; D002292:Carcinoma, Renal Cell / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D007680:Kidney Neoplasms / Q000737:chemistry / Q000473:pathology*; D009154:Mutation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D000199:Actins; D016159:Tumor Suppressor Protein p53