Primary Ewing sarcoma of the kidney presenting as haematuria in a pregnant woman - A case report highlighting the diagnostic and therapeutic dilemmas of the condition in pregnancy.

Primary Ewing sarcoma of the kidney is an extremely rare yet aggressive tumour. We present a 31-year-old pregnant female who presented to the emergency department with macroscopic haematuria and an ultrasound scan demonstrating a right renal mass. On magnetic resonance imaging, the lesion had features concerning for malignancy. She underwent a radical nephrectomy and was commenced on a personally tailored chemotherapy regime designed to permit healthy delivery of her baby while adequately treating her disease. This highlights an extremely rare differential for a renal mass which should be considered in rapidly growing renal tumours of a young patient.

Aggressive Angiomyolipomas: the Clandestine Epithelioid Variant.

Epithelioid angiomyolipoma is a rare mesenchymal derived neoplasm of the kidney. Thought to be a variant of classical angiomyolipoma, a benign tumour, its malignant potential has been highlighted by case reports of loco-regional and distant metastasis. Given the potentially adverse clinical course associated with epithelioid angiomyolipoma compared to classical angiomyolipoma, the distinction and comprehensive histological characterisation of this rare entity is essential.

Clear cell papillary renal cell carcinoma: a potential mimic of conventional clear cell renal carcinoma on core biopsy.

Clear cell papillary renal cell carcinoma (CCP-RCC) is a recently described, relatively uncommon variant of renal cell carcinoma (RCC) with a reported incidence of 4.1%. Thought to only arise in those with end stage renal disease, CCP-RCC is increasingly identified in those without renal impairment. CCP-RCCs have unique morphologic, genetic, and immunohistochemical features distinguishing them from both conventional clear cell renal cell carcinomas and papillary renal cell carcinomas. Immunohistochemically, these tumors are positive for CK7 and negative for CD10 and racemase. This is in contrast to conventional cell renal cell carcinomas (CK7 negative, CD10 positive) and papillary cell carcinomas (CK7, CD10, and racemase positive). These tumours appear to be indolent in nature, with no current documented cases of metastatic spread. We present the case of a 42-year-old female who presented with an incidental finding of a renal mass that on a core biopsy was reported as clear cell carcinoma, Fuhrman grade 1. She subsequently underwent a radical nephrectomy and further histological examination revealed the tumor to be a clear cell papillary renal cell carcinoma, Fuhrman grade 1.