What's the Take Home?

A 67-Year-Old Man With A Long History of Renal Abnormality and a Change in Hematocrit

Volume 60 - Issue 10 - October 2020

AUTHOR:
Ronald N. Rubin, MD1,2—Series Editor

AFFILIATIONS:
1Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
2Department of Medicine, Temple University Hospital, Philadelphia, Pennsylvania

CITATION:
Rubin RN. A 67-year-old man with a long history of renal abnormality and a change in hematocrit. Consultant. 2020;60(10):20-21, 24. doi:10.25270/con.2020.10.00001

DISCLOSURES:
The author reports no relevant financial relationships.

CORRESPONDENCE:
Ronald N. Rubin, MD, Temple University Hospital, 3401 N Broad St, Philadelphia, PA 19140 (blooddocrnr@yahoo.com)

 

A 67-year-old man presented to the office for a general medical examination. He had no new or significant symptoms to report. He is a former smoker, having stopped about 10 years ago. The smoking has left him with mild to moderate chronic obstructive pulmonary disease with occasional wheezing but few problems with routine daily life—he is able to walk several blocks without dyspnea.

Of particular interest, 16 years ago, abdominal ultrasonography for gastrointestinal tract reasons had shown an incidental 2.3-cm renal mass. In accordance with the patient’s choice, the mass had been managed with no intervention other than serial imaging at 12- to 18-month intervals, the most recent of which had been 3 years ago and had shown the mass to have grown to 3.6 cm. He had not returned thereafter until now, and he has never experienced flank pain or hematuria.

At the current visit, examination of the lungs revealed bilateral expiratory wheezes, and flank and abdominal examination revealed no mass or pain. Office urinalysis results were negative for hematuria. Results of a biochemistry profile were totally within normal limits, including a serum creatinine level of 1.1 mg/dL, but results of a complete blood cell count (CBC) had changed since his studies of 3 years ago. His white blood cell count and platelet count were normal, but his hematocrit concentration had risen from the 43% to 44% range to 53%, with normal mean corpuscular volume and normal cell morphology on smear.

Answer: C, order a CT scan of the pelvis and kidneys.

The clinical scenario presented here opens a gateway into a discussion of the management of small renal tumors. This is important, since (1) in our era of frequent and ubiquitous imaging, so many small renal lesions are discovered incidentally, and (2) even in those found to be malignant, the behavior of renal carcinoma is quite variable and capricious in its natural history.

For our purposes, and because most of the available literature uses this definition, small renal tumors are defined as lesions discovered on imaging that are 4 cm or smaller.1 The initial maneuver in these cases is an attempt to define, with the least invasiveness and lowest risk of morbidity, whether the mass is malignant. Several methodologies have been established to classify contrast CT findings of cystic renal masses, which can be presented in a very simplified manner as follows (the Bosniak classification):

Class I is essentially a simple cyst with the density of water and thin walls without septa, calcifications, solid components or, very importantly, enhancement. Such lesions are considered benign. Class II masses are also almost always benign and are cystic but can contain fine, thin septa with some enhancement and/or fine calcifications. These lesions should be monitored with follow-up studies. Class III lesions cross the line in that they are indeterminate regarding malignancy. They are cystic with thickened, irregular walls or septa. Again, and very importantly, they manifest significant enhancement. Finally, class IV lesions are frequently (80% or more) malignant and, in addition to any of the characteristics above, demonstrate soft tissue masses adjacent to but independent of any cyst wall or septa. These are indications for surgical removal.2 Since we physicians cannot help ourselves when it comes to reclassifying and subclassifying just about any set of findings ad infinitum, there are subtle subcategories of these classifications that are beyond this scope of this discussion. Meanwhile, most solid enhancing lesions that are discovered usually require proceeding to biopsy.1

The next process is managing a small renal tumor that is either borderline malignant radiologically or even proven to be malignant by biopsy but that is “small” in size. This is a much less tightly defined issue because of the following variables: (1) The older “one size fits all” radical surgical removal to negate all cancer-related risk did not result in overall survivor benefit in small renal tumors. (2) There is a very wide range of mortality risk from such small renal tumors. (3) Since most patients with small renal tumors are older than 60, there is significant mortality associated with removal, particularly when there is preexisting renal dysfunction. And (4), although there are and continue to be evolving experiential data, there are essentially no randomized controlled trials.1-3

So, we must rely on a listing of available approaches and specialty guidelines for applying them. Active surveillance is monitoring the lesion size by serial follow-up imaging with ultrasonography, CT, or magnetic resonance imaging, the latter two with greater ability for detail. Observational studies have found that small incidental masses have little growth to 3 years or more, and serial follow-up imaging is part of the American Urological Association guidelines in patients of any age.4 Surgical removal these days means, when the pathology allows by location (eg, relationship to renal vasculature and collecting system),1,2,4 nephron-sparing surgery, which provides good oncologic outcome with less overall morbidity (and specifically renal insufficiency) compared with radical nephrectomy.1 Finally, a variety of image-guided ablation techniques (cryoablation or radiofrequency ablation) can be considered for small (<3 cm) tumors in elderly patients or other patients who are poor surgical candidates because of the risk of comorbidity.2

Now, returning to the case presented above, it would seem that when his renal mass was first discovered incidentally, he was young enough that an aggressive approach—biopsy and removal—might have been best, but the patient did not wish to do so and preferred a monitoring approach. The small tumor size made this decision not unreasonable, and a very long time passed before the tumor went rogue. In fact, even 13 years later, the lesion had only grown from 2.3 cm to 3.6 cm, still a “small tumor” by most definitions. But after a period of being lost to follow-up, an interesting clue appears: erythrocytosis. When one encounters erythrocytosis, current evaluation usually entails checking JAK2 for polycythemia vera (autonomous marrow) and checking the erythropoietin (EPO) level (a normal or elevated level suggests secondary causes). And 99% of secondary causes are renal—benign or malignant cysts and solid tumors. The course was somewhat obvious in this case given his history, and although the degree of growth was surprising, the underlying situation was not, and the correct approach, Answer C, was demonstrative and diagnostic.

As discussed, studies for myeloproliferative disease/polycythemia vera (JAK2) and secondary erythrocytosis (EPO levels) in Answer B are not incorrect approaches on their face, but they are not optimal in the presented patient’s case. Regarding Answer A, phlebotomy is an early treatment initiative for patients with myeloproliferative disease and results in decreased thromboembolic morbidity and mortality in that patient group. There are no data to support that similar maneuvers are required for secondary causation situations. And again, our patient had a red-flag history of renal causation, and a malignant one at that, such that Answer A is not the initial or optimal maneuver. Finally, the patient’s history suggests that an image will suffice and, in any event, would be required before any biopsy, surgery, or ablative maneuver of any kind, making Answer D incorrect.

PATIENT FOLLOW-UP

Results of a repeated CBC were essentially identical and confirmed the presence of an abnormally high hematocrit concentration that was significantly elevated from just 1 year ago. He was sent immediately for renal ultrasonography, which demonstrated an alarmingly rapid change. The right kidney remained normal in size at 11.4 cm. The left kidney was now 14.0 cm, with a heterogeneous, isoechoic, exophytic solid mass measuring 9.0 × 9.4 × 8.6 cm at the inferior pole of the left kidney. A subsequent CT scan demonstrated hyperdensity with a centrally necrotic center and coarse calcifications. Retroperitoneal adenopathy was present. The renal vein appeared uninvolved and patent.

For completeness, blood studies also revealed absent JAK2 and an elevated EPO level of 112 mU/mL. He was urgently referred to urology, where the surgically appropriate approach is being explored.

TAKE-HOME MESSAGE

Small renal masses, usually defined as 4 cm or smaller, are an extremely common incidental finding in patients undergoing abdominal imaging. A very detailed and specific set of radiologic criteria has evolved, which can nicely initially categorize lesions as class I (benign), class II (likely benign), class III (indeterminate), and class IV (malignant); this classification then guides management choices, balancing oncology mortality risk and therapy morbidity and mortality risk in most patients. Even when malignancy is suspected or demonstrated, small (2-3 cm) tumors show slow growth, at least initially, and a wide range of subsequent behavior. Management regimens include serial monitoring, surgical removal, and ablation techniques, which need to be matched to patient findings of pathologic anatomy and demographics such as age and comorbidities (especially coexisting renal disease), as well as informed patient preference.

REFERENCES:

  1. Kang SK, Bjurlin MA, Huang WC. Management of small kidney tumors in 2019. JAMA. 2019;321(16):1622-1623. doi:10.1001/jama.2019.1672
  2. Gill IS, Aron M, Gervais DA, Jewett MAS. Small renal mass. N Engl J Med. 2010;362(7):624-634. doi:10.1056/NEJMcp0910041
  3. Kutikov A, Egleston BL, Wong Y-N, Uzzo RG. Evaluating overall survival and competing risks of death in patients with localized renal cell carcinoma using a comprehensive nomogram. J Clin Oncol. 2010;28(2):311-317. doi:10.1200/JCO.2009.22.4816
  4. Campbell S, Uzzo RG, Allaf ME, et al. Renal mass and localized renal cancer: AUA Guideline. J Urol. 2017;198(3):520-529. doi:10.1016/j.juro.2017.04.100