RESUMO
Atrophic kidney like lesion (AKLL) is a recently described benign entity with only 14 cases reported so far. Genitourinary Pathology Society proposed inclusion of AKLL as a provisional entity in 2021. It mimics thyroid follicular-like carcinoma of kidney as it has a follicular architecture. We report a case of an 18-year-old female with detection of renal mass, while the patient was being investigated for abdominal pain. Mediastinal nodes were also enlarged with detection of necrotizing granulomas on biopsy. Histology revealed a tumor enveloped by a thick capsule with smooth muscle fibers, varying sized follicles, interspersed atrophic tubules, and calcifications. Immunohistochemically, the “cystic follicles” show WT1 +/PAX8 -/CK7-phenotype, while atrophic tubules present between “cystic follicles” harbor WT1 -/PAX8 +/CK7 + phenotype. Morphological diagnosis and differential diagnosis will be discussed.
RESUMO
The thyroid–like follicular renal cell carcinoma is an extremely rare kind of kidney neoplasms with unique clinicopathological features. The definitive diagnosis relies mainly on characteristically histological morphology, immunophenotype and clinical data. A case of thyroid-like follicular renal cell carcinoma with typically morphological character was reported. The patient suffered from low back pain, frequent urination, with the renal MR showing the right renal sinus nodule.The mass was located at the lower pole of the right kidney-close to the renal portal below the renal pelvis. After receiving simple resection of the right kidney tumor, the case was diagnosed as thyroid-like follicular renal cell carcinoma by pathological examination,and no recurrence or metastasis was observed after 6-month follow up.