Ca kidney vs inflammatory lesion

This 18 years boy admitted in medicine ward with 7 days history of fever without chill .Fever subsided after antibiotics in medicine ward.

Blood investigation r normal.
Urine RE n CS normal.
Referred to us when usg showed around 4 cm mass lesion left kidney.
We did CECT KUB. attached.Radiologist not sure whether malignant or inflammatory lesion.
 So MRI done also radiologist not sure.
We advised radical nephrectomy to patient party based on imaging.
Patient party not willing for RN without confirmation of diagnose as he is young boy.
How to investigate him further?or these images r sufficient..
Radical nephrectomy or partial nephrectomy active surveillance or ablation?

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  • Utsav Shah
    Utsav Shah
    18 Mar 2020 07:44:11 PM

    It can be any benign lesion Like a metanephric adenoma or an oncocytoma or even an RCC. The age is the biggest factor to go against upfront RN. 

    No harm in doing a renal biopsy.
    Never seen such a case. 
    Seniors on this forum can guide. 

  • Dr. Anil Takvani
    Dr. Anil Takvani
    19 Mar 2020 08:31:17 AM

    The SOL is in the right kidney.

    On CECT it is well enhancing.
    Blood counts and urine normal.
    As radiologists are confuse and CECT findings are not typical(Atypical), I would like to go for FNAB of right renal mass. Posting link of article published in cyto-journal on role of FNAB in era of modern imagining.
    Another link of article stating one of the indication:
    Renal mass presumed secondary to infection: In this setting, renal mass biopsy is performed because of the possibility that the “mass” is focal bacterial pyelonephritis or a developing abscess that can be managed with antibiotics (with or without aspiration) instead of surgery.

  • Pankaj N Maheshwari
    Pankaj N Maheshwari
    19 Mar 2020 08:43:34 AM

    I agree Anil, even i would advice CT guided biopsy.

  • Dr Prashant Mulawkar
    Dr Prashant Mulawkar
    20 Mar 2020 11:47:15 PM

    RCC has been known to present with systemic symptoms. (paraneoplastic syndromes)

    It is fairly common for RCC to be detected “incidentally”

    Although negative urine culture does not rule out renal abscess, I would expect it to be positive in majority of renal abscesses patients

    Core needle biopsy has sensitivity of 70-100% and specificity of around 100%. The main complications being bleeding and tumour seeding.

    Whereas FNA biopsy has sensitivity of 76-97%.

    The main indications for doing a core needle biopsy or a FNA biopsy are

    (1) solid renal masses with atypical radiological features or poorly characterized on imaging studies due to lack of intravenous contrast or body habitus

    (2) confirmation of radiologically suspected RCC in inoperable patients (advanced stage disease or poor surgical candidate status)

    (3) kidney mass in a patient with a prior history of other malignancy

    (4) miscellaneous (drainage of abscess, indeterminate cystic lesion, urothelial carcinoma

    The “biopsy” mainly benefits the patients with renal abscess by providing a diagnosis and therapy in form of drainage.

    Will I do a biopsy?


    What will I do after biopsy?

    If it drains pus, put in a tube

    If pus is recovered, a chronic renal abscess can be diagnosed and treated with percutaneous drainage. However, if blood or necrotic debris is recovered, an infectious cause is unlikely and surgical removal is usually indicated.

    If it does not drain pus and HP report is malignancy: surgery

    If it does not drain pus and HP is inconclusive, I would assess whether this patient is likely to come back to follow up. This can be judged by the body language of the patient and how they behave. If I am sure that he would come back, repeat imaging, or else suggest surgery.

    If I am not sure that he would follow up, I refer the patient to a center of expertise.

    Regarding the role of PET CT, I would post little later.

  • Tikenjit Mazumdar
    Tikenjit Mazumdar
    21 Mar 2020 11:52:12 AM

    Super explanation sir... Thank u ...understood

  • Dr Prashant Mulawkar
    Dr Prashant Mulawkar
    21 Mar 2020 11:55:12 PM


    The question that I am trying to answer is, “Can we do some non invasive test to know whether this is a cancer or an abscess?”

    Can I do a PET CT?

    Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-dglucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. PET CT can help us predict the grade of RCC. The SUVs of high-grade clear cell RCC is significantly higher when compared with that of the control benign lesions and low-grade tumors. An optimal SUV cutoff value of 3.0 had 89% sensitivity and 87% specificity. PET CT is also helpful in prognosis of the lesion. High SUVmax correlates with poor prognosis. It is helpful in predicting extrarenal disease. It is helpful in restaging and detecting recurrence. It can differentiate bland emobli from tumour thrombus.

    However, FDG is not specific for malignant neoplasm. Increased uptake can be seen in many benign tumors and non- neoplastic processes.

    False positives: concomitant inflammatory/infectious disease , postoperative scar, postradiation inflammation

    False Negatives: small size of lesion and limited spatial resolution of PET scanner, close proximity of the lesion to the urinary tract where there is physiologic urine activity.


    Gallium scan/ Indium Scan

    Could not find conclusive literature. Yet searching for it


    Why not see the existing CT again?

    CT with contrast agent may show rim enhancement with central hypo-attenuation and thickened septa. Increasing of adjacent fat signaling and thickening of perinephric fascia are suggestive of an infectious process rather than a neoplasm


    How do I differentiate Tumour from abscess on imaging?


    Abscess: Variable echogenicity but tend to be sonolucent. Internal septation may occur

    Tumour: Solid or cystic with variable echogenicity to the surrounding parenchyma.

    Plain CT
    Abscess: Low attenuation mass (0-25 HU), Gerota's fascia thickening, stranding and obliteration of perinephric fat.

    Tumour: Soft tissue attenuation between 20 and 70 HU. Some lesions frequently have necrosis area and some calcification

    Contrast CT

    Abscess: The “rind sign”, a rim of peripheral enhancement with central hypoattenuation and thickened septa.

    Tumour: Variable enhancement, usually less than normal cortex. Larger lesions have irregular enhancement due to necrosis area


    Abscess: Hypo-intensity on T1-weighted images and hyper-intensity on T2-weighted images

    Tumour: Heterogeneous on T1-weighted images. Hypo-intensity for papillary RCC and hyper-intensity for clear cell RCC on T2-weighted images. (mnemonic to remember this: clear is water, water is H2O, Water is hyperintense on T2 weighted images)




    Liu Y. The place of FDG PET/CT in renal cell carcinoma: value and limitations. Frontiers in oncology. 2016 Sep 6;6:201.


    Wang HY, Ding HJ, Chen JH, et al. Meta-analysis of the diagnostic performance of [18F]FDG-PET and PET/CT in renal cell carcinoma. Cancer Imaging. 2012;12(3):464–474. Published 2012 Oct 26. doi:10.1102/1470-7330.2012.0042

    Kumar R, Shandal V, Shamim SA, Jeph S, Singh H, Malhotra A. Role of FDG PET-CT in recurrent renal cell carcinoma. Nuclear medicine communications. 2010 Oct 1;31(10):844-50.

    Censullo A, Vijayan T. Using nuclear medicine imaging wisely in diagnosing infectious diseases. InOpen forum infectious diseases 2017 Jan 1 (Vol. 4, No. 1). Oxford University Press.

    Raharja PA, Hamid AR, Mochtar CA, Umbas R. Case of perinephric abscess disguising as renal tumor. Urology case reports. 2018 May;18:35.

    26 Mar 2020 04:44:21 PM

    In a different vein sir my question is for inoperable T3/4  mass;

    Indication(s) for lap assist core biopsy?

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