Very Low Risk T1a Renal Cell Carcinoma Presenting with Pathological Fracture Caused by a Solitary Metastases to the Contralateral Arm

Renal Cell Carcinomas are notorious for asynchronous metastases, atypical metastatic sites and late relapses even decades after nephrectomy. It is quite rare though for RCCs to present as metastatic, solitary and symptomatic bone lesions. Even more uncommon is a solitary bone metastasis much larger that the primary tumour caused by a low risk primary T1a RCC which would have otherwise been eligible for active surveillance.An otherwise healthy 68-year-old female was seen by the orthopaedics for right shoulder and upper arm worsening pain. Imaging showed a pathological fracture caused by a 5.5 cm lytic lesion involving the coracoid process and proximal humerus. She underwent proximal humeral replacement and histology of the lesion showed metastatic RCC. Whole body CT scan revealed a primary tumour of the left kidney less than 4cm in diameter. The patient underwent laparoscopic radical nephrectomy and diagnosis of a T1a, clear cell RCC without adverse pathological features was confirmed. She has been on systematic therapy with oral TKIs since and is free from recurrence at 12-months follow up.Even T1a RCCs without adverse pathological features can give rise to distant metastases following unpredictable patterns of spread thereby questioning the safety of active surveillance in healthy and fit patients.