Delayed Presentation of Metastatic Renal Cell Carcinoma as an Arteriovenous Malformation Mimicking Vascular Tumour of the Forearm

Abstract

Introduction The development of metastatic renal cell carcinoma (RCC) many years after a nephrectomy is not common but has been reported. A metastasis appearing as a hypervascular tumour, mimicking an arteriovenous malformation (AVM), is a highly unusual phenomenon, with a biopsy required for diagnostic confirmation. Surgery is an option for a solitary metastatic lesion amenable to complete excision, with proven survival benefits. However, widespread metastatic disease carries a very poor prognosis, and is best treated with systemic agents such as anti-angiogenic drugs or tyrosine kinase inhibitors. Report A 58 year old man developed an AVM mimicking a vascular tumour within his left brachioradialis muscle 10 years after a nephrectomy for RCC. Ultrasound and magnetic resonance imaging did not reveal any suspicious features of the vascular lesion. The lesion was successfully removed surgically, and was later proven histopathologically to be metastatic RCC. Further imaging showed widespread metastatic disease, and the patient survived only 15 months after receiving tyrosine kinase inhibitor therapy. Discussion This case report aims to highlight a few important points: RCC metastases may be hypervascular, mimicking an AVM. A long disease free interval does not necessarily exclude recurrence or metastasis, as in this case, therefore long term surveillance is recommended. A high index of suspicion must be maintained to avoid delay in treatment, and biopsy of any suspicious lesion for histological examination is mandatory, albeit after many years of cancer remission. Whole body imaging with computed tomography or positron emission tomography computed tomography may detect clinically occult recurrence or metastases, and is important to guide further treatment.

Renal Cell Carcinoma With Facial Swelling and Nasal Obstruction as Primary Presentation

“…As in our case, a hypervascular tumour was well demonstrated on conventional angiogram in which due to its hypervascularity, histopathological sampling was challenging. In another case, as reported by certain writers, RCC can metastasis in the form of an arteriovenous malformation, as Caunter G et al discovered (10). As a result, a hypervascular tumour is unlikely to be metastatic in origin.…”

Skeletal Muscle Metastasis From Renal Cell Carcinoma: A Case Series and Literature Review

“…The SMM from RCC occurs in <1% of patients and is described only in case reports ( 9 ). The reported reasons for the rarity of SMM from RCC can be summarized as the high vascularization of muscles; the lactic acid production in skeletal muscle may lead to angiogenesis resistance ( 46 , 47 ); high concentrations of free radicals, local temperature fluctuations, skeletal muscle-derived peptide factor, protease inhibitors, lymphocytes, and natural killers may inhibit metastasis ( 12 , 48 – 50 ); specific receptors which affect the metastasis potential of RCC may be missing or scarce in muscles ( 51 , 52 ).…”

“…The median survival time of untreated patients with metastatic RCC was 6–12 months, and the 5-year survival rate was <20% ( 58 ). But for local metastases, surgical resection is beneficial to prolong survival ( 9 ) and five-year survival rates are between 35 and 50% after surgical therapy for solitary metastasis ( 17 , 59 ). Besides, it was also reported that in patients with multiple and non-lung-only metastasis, complete metastasectomy can bring the benefit of a 5-year survival rate to 32.5 vs. 12.4% without complete resection ( 60 ).…”

Mechanisms Underlying the Rarity of Skeletal Muscle Cancers

“…Moreover, using computed tomography, a 2010 study detected SKM metastases in just 61/5170 (1.2%) patients with metastasized cancer [20]; metastases were most commonly associated with primary tumors of the genitals (24.6%), gastrointestinal tract (21.3%), urinary system (16.4%), and melanocytes (13.1%). Another study reported SKM metastasis occurred in <1% of patients with kidney cancer [21]. In addition, a 2012 study [5] confirmed the rarity of SKM metastases in patients with lung cancer (1.6%), with most metastases occurring in trunk muscles, suggesting that SKM metastases likely arise from adjacent tumors.…”