Atrophic kidney-like lesion: A rare benign entity and mimicker of thyroid follicular-like carcinoma of kidney

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.

Phenotype analysis of 9 cases with mutations in PKHD1 gene / 中华肾脏病杂志

Objective To summarize the clinical features of 9 cases with mutations in PKHD1 gene for a better understanding of its phenotype.Methods Clinical data of nine cases with mutations in PKHD1 gene were summarized from January 2011 to December 2016 in our center,including clinical manifestations,laboratory findings,imaging data and family investigation.Next generation sequencing was used to screen 4000 genes in case 1 to 4 and whole exons in case 5 to 9.Significant variants detected by next generation sequencing were confirmed by conventional Sanger sequencing.Segregation analysis was performed using parental DNA samples.Relevant literature was reviewed.Results Among these 9 cases,5 are male,4 are female.The average age of onset was 2.6 years old (ranging from 0.5-5.2 years).Renal ultrasound revealed that all 9 cases had cysts in bilateral kidney,7 cases with enlarged kidney,1 case with normal size kidney,1 case with normal size kidney,and 1 case with bilateral renal atrophy.Two cases with renal artery stenosis,1 case with focal narrowing in left main branch and 1 case with vesico-ureteral reflux were found.Among the 9 cases,3 cases had homozygous mutations,and 6 cases had compound heterozygous mutations,including 1 nonsense mutation,1 frameshift mutation and 15 missense mutations.There were 2 cases with 3 heterozygous mutations,2 c.5935C ＞ T mutations and 2 eases with C.5869G ＞ A mutations.A total of 10 new mutations were identified.Conclusion Patients with mutations in the PKHD1 gene had normal size kidney,or even atrophic kidney.Renal artery stenosis,vesicoureteral reflux and bronchial stenosis were all first reported in patients with mutations in PKHD1 gene.The novel mutations,c.274C ＞ T,c.9059T ＞ C,c.8996delG,c.281C ＞ T,c.10424T ＞ A,c.7092T ＞ G,c.4949T ＞ C,c.5869G ＞ A,c.6197A ＞ G and c.1877A ＞ G further expanded the mutation spectrum of PKHD1 gene.