November 2016 Imaging Case of the Month

Michael B. Gotway, MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, Arizona USA

Imaging Case of the Month CME Information  

Members of the Arizona, New Mexico, Colorado and California Thoracic Societies and the Mayo Clinic are able to receive  0.25 AMA PRA Category 1 Credits™. Completion of an evaluation form is required to receive credit and a link is provided on the last panel of the activity.

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.25 hours

Lead Author(s): Michael B. Gotway, MD. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity. 

Learning Objectives:
As a result of this activity I will be better able to:    

1. Correctly interpret and identify clinical practices supported by the highest quality available evidence.
2. Will be better able to establsh the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Will improve the translation of the most current clinical information into the delivery of high quality care for patients.
4. Will integrate new treatment options in discussing available treatment alternatives for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at the Arizona Health Sciences Center.

Current Approval Period: January 1, 2015-December 31, 2016

Clinical History: A 38-year-old man presented to his primary care physician with complaints of pruritus, jaundice, and poor appetite. The patient had been diagnosed with hypertension one year earlier and was treated with hydrochlorothiazide and an angiotensin-converting enzyme inhibitor, but evidently did not tolerate the regimen well, and developed “tea-colored” urine following initiation of this therapy. He was also recently diagnosed with diabetes mellitus and also complained of intermittent right upper quadrant pain.

Laboratory data, including white blood cell count and serum chemistries were within normal limits. Oxygen saturation on room air was 99%.

Frontal and lateral chest radiographs (Figure 1) were performed.

Figure 1. Frontal (A) and lateral (B) chest radiography.

Which of the following statements regarding the chest radiograph is most accurate? (Click on the correct answer to proceed to the second of seven pages)

1. Frontal and lateral chest radiography appears normal
2. Frontal and lateral chest radiography shows a focal, poorly defined right base opacity
3. Frontal and lateral chest radiography shows bilateral peribronchial and mediastinal lymph node enlargement
4. Frontal and lateral chest radiography shows cardiomegaly
5. Frontal and lateral chest radiography shows upper lobe bilateral linear and reticular abnormalities

Cite as: Gotway MB. November 2016 imaging case of the month. Southwest J Pulm Crit Care. 2016;13(5):207-15. doi: http://dx.doi.org/10.13175/swjpcc112-16 PDF 

Medical Image of the Week: Renal Cell Carcinoma Metastasis

Figure 1. Panel A: Axial CT image noncontrast showing small pulmonary nodules concerning for metastasis. Panel B: Axial CT image depicting 15 cm mass, originating from the right acetabulum and adjacent iliac bone. Panel C: Coronal CT image showing prominent left renal cyst measuring almost 40 mm. Panel D: Coronal CT image displaying femoral head intact but surrounded by abnormal soft tissue, concerning for neoplasm. There is bony destruction and lytic process in the anterior and posterior pillars of the right acetabulum.

A 65-year-old man was complaining of progressive weakness and right knee pain with limping since November 2014 was admitted recently to a local hospital and treated for chronic kidney disease related anemia, Klebsiella urinary tract infection and methicillin-sensitive Staphylococcus aureus wound infections. He was discharged to rehab, but continued to have progressive weakness, pain and limping. He was sent to our hospital for further evaluation and imaging.

CT of the abdomen and pelvis non contrast, due to decreased glomerular filtration rate, revealed a 15 cm mass originating from the right acetabulum and adjacent iliac bone with bony destruction and lytic processes (Figure 1). The femoral head is also surrounded by abnormal soft tissue (Figure 1D). There were also small pulmonary nodules (Figure 1A), small lymph nodes in the transverse mesocolon and retroperitoneum, and an enlarged left adrenal gland concerning for other metastasis.

CT guided biopsy of the lesion revealed a neoplastic process composed of atypical cells with centrally placed nuclei, abundant clear cytoplasm arranged in a vascular network. Immunohistochemical stains demonstrated positivity for the following: vimentin, low molecular weight keratin, CD10, RCCA, and PAX-8. These findings are consistent with metastatic renal cell carcinoma.

A total body bone scan with Tc-99m methylene diphosphonate, performed to locate other osseous metastasis, was negative for distant metastasis other than the large destructive lesion destroying the right ileum previously noted on CT.

Renal cell carcinoma (RCC) is a cortical tumor with malignant cells originating from the epithelial lining of the proximal tubules. Renal cancer is amongst the 10 most common cancers in both men and women, with RCC accounting for about 80% of the total incidence and mortality (1). RCC has been referred to as “the internist’s tumor” as it can cause systemic symptoms unrelated to the renal cancer. The classic triad of RCC (flank pain, hematuria, and a palpable abdominal renal mass) occurs in at most 9 percent of patients (1). Most cases of RCC are diagnosed incidentally on radiographic investigation done for other reasons. Unfortunately, many patients are asymptomatic until the disease is advanced. At presentation, approximately 25% of individuals either have distant metastases or advanced local disease (2). Biopsy is not usually required to diagnose RCC. Contrast-enhanced CT can be used to diagnosis and stage RCC. 

Stage IV disease has a median survival of about 12 months with systemic cytokine therapy and 28 months with targeted therapies, based on analyses from the International Metastatic RCC Database Consortium (IMDC) (1,3).

Erin Yen MS¹, Benjamin Rayikanti MD², Yunuen Valenzuela MD³, Jennifer Segar MD³

¹ Midwestern University Arizona College of Osteopathic Medicine, Phoenix

² Tucson Hospitals Medical Education Program

³ Department of Internal Medicine, Banner University Medical Center Tucson

Tucson AZ USA

References

1. American Cancer Society. Cancer Facts & Figures 2016. Atlanta, GA: American Cancer Society; 2016. Available at: http://www.cancer.org/research/cancerfactsstatistics/cancerfactsfigures2016/ (accessed 9/14/16).
2. DeKernion JB. Real numbers. In: Campbell's Urology, Walsh PC, Gittes RF, Perlmutter AD (Eds), WB Saunders, Philadelphia 1986. p.1294.
3. Heng DY, Choueiri TK, Rini BI, et al. Outcomes of patients with metastatic renal cell carcinoma that do not meet eligibility criteria for clinical trials. Ann Oncol. 2014 Jan;25(1):149-54. [CrossRef] [PubMed]

Cite as: Yen E, Rayikanti B, Valenzuela Y, Segar J. Medical image of the week: renal cell carcinoma metastasis. Southwest J Pulm Crit Care. 2016;13(3):135-6. doi: http://dx.doi.org/10.13175/swjpcc068-16 PDF

Medical Image of the Week: Renal Infarction

Figure 1. Contrast enhanced CT of the abdomen showing the majority of the right kidney infarcted with some preservation of the superior pole. 

A 79-year-old woman with past medical history of persistent atrial fibrillation not on anticoagulation, coronary artery disease, hypertension, diabetes, and hyperlipidemia presented with right flank pain accompanied by nausea and vomiting for two days. Laboratory studies showed leukocytosis with creatinine of 1.2. Urinalysis was negative for signs of infection and red blood cells. However, despite being on analgesic, she continued to have flank pain. The patient subsequent underwent CT scan of the abdomen and pelvis the next day, which showed that the majority of the right kidney was infarcted. Interestingly, there were two right-sided renal arteries and a thrombus was seen in the inferior main right renal artery. The superior pole of the right kidney was preserved as a result of the patent accessory renal artery. Due to delayed presentation of more than 48 hours after onset of pain, the tissue could not be re-vascularized by vascular surgery. Her renal function remained intact and her flank pain gradually improved. 

Acute renal infarction is difficult to diagnose as it is mimicked by more commonly seen causes such as pyelonephritis and nephrolithiasis. Pain in the unilateral flank and/or abdomen is the hallmark presenting feature, however nausea, vomiting, and fever are also common. New or increasingly severe hypertension is found in approximately half of acute renal infarction diagnosis, a sign that should raise clinical suspicion in similar clinical scenario. Proteinuria is another feature that may be present on urinalysis. Creatinine elevation consistent with acute kidney injury (AKI) occurs in approximately 30-40% of cases (1). Leukocytosis is commonly seen in as many as three-quarters of patients with renal infarct. The most common laboratory finding in renal infarction is elevation of LDH, although this is nonspecific and does not necessarily aid in specific diagnosis (2). Diagnosis is usually made through contrast enhanced CT abdomen, however angiography may also be used.

Our patient also had two renal arteries supplying her right kidney, allowing for the superior pole of her renal parenchyma to be spared and thus her kidney function. The kidney tolerates ischemia for approximately 12 hours, making early diagnosis paramount. In patient’s such as the one described here that involves all or majority of one kidney, embolectomy is recommended because of favorable outcomes in prior studies (3). In summary, the challenge of early diagnosis of renal infarction lies in the recognition of nonspecific clinical symptoms and signs in an already rare occurrence. Recognizing these signs within hours of presentation may be the difference between viable renal tissue and death of a kidney. Keeping a high suspicion in patients with atrial fibrillation will also aid in early diagnosis.

Jessica August MD and Jennifer J Huang DO

Department of Internal Medicine

University of Arizona

Tucson, AZ

References

1. Bae EJ, Hwang K, Jang HN, Kim MJ, Jeon DH, Kim HJ, Cho HS, Chang SH, Park DJ. A retrospective study of short- and long-term effects on renal function after acute renal infarction. Ren Fail. 2014;36(9):1385-9. [CrossRef] [PubMed]
2. Antopolsky M, Simanovsky N, Stalnikowicz R, Salameh S, Hiller N. Renal infarction in the ED: 10-year experience and review of the literature. Am J Emerg Med. 2012;30(7):1055-60. [CrossRef] [PubMed]
3. Tsai SH, Chu SJ, Chen SJ, Fan YM, Chang WC, Wu CP, Hsu CW. Acute renal infarction: a 10-year experience. Int J Clin Pract. 2007;61(1):62-7. [CrossRef] [PubMed]

Reference as: August J, Huang JJ. Medical image of the week: renal infarction. Southwest J Pulm Crit Care. 2015;10(4):195-6. doi: http://dx.doi.org/10.13175/swjpcc023-15 PDF

Medical Image of the Week: Metastatic Collecting Duct Carcinoma

C

Figure 1. Transverse section of CT chest and abdomen shows enhancing pleural nodularity (yellow arrows) with a pleural effusion.

Figure 2.  Transverse section of CT abdomen shows heterogeneous enhancing mass in the right kidney (red arrow).

Figure 3. Coronal section of CT chest and abdomen showing a large right pleural effusion (yellow arrow) and atelectatic lung with mediastinal shift to the left. Red arrow points to the heterogeneous mass in the right kidney.

A 40-year-old woman home health nurse presented to the ED with intermittent right sided sharp chest pain and progressive dyspnea for 2 weeks. On admission she was found to be in respiratory distress. Chest x-ray revealed a massive right sided pleural effusion. Thoracic CT scan with contrast confirmed a large right pleural effusion with associated enhancing pleural nodularity also involving the diaphragmatic surface (Figure 1).  The visualized part of the abdomen revealed a mass in the midpole of right kidney (Figure 2). Subsequent CT scan of the abdomen with contrast revealed a heterogeneous enhancing mass in the right kidney suspicious for malignancy (Figure 3) and multiple paracaval lymph nodes. Thoracentesis revealed a hemorrhagic pleural effusion and during subsequent right video-assisted thoracoscopy showed disseminated tumorlets along the diaphragm and pleura. Pleural biopsy and fluid cytology was consistent with metastatic poorly differentiated collecting duct carcinoma of the kidney. The patient is currently getting outpatient chemotherapy. Collecting duct carcinoma of the kidney is an unusual variant of renal cell carcinoma and accounts for about 1% of all renal cell carcinomas (1). This variant has a poor prognosis and frequently metastasizes to the lung and liver.

Chandramohan Meenakshisundaram, MD

Nanditha Malakkla, MD

St. Francis Hospital.

Evanston, IL

Reference

1. Wang X, Hao J, Zhou R, Zhang X, Yan T, Ding D, Shan L, Liu Z. Collecting duct carcinoma of the kidney: a clinicopathological study of five cases. Diagn Pathol. 2013;8:96. [CrossRef] [PubMed]

Reference as: Meenakshisundaram C, Malakkla N. Medical image of the week: metastatic collecting duct carcinoma. Southwest J Pulm Crit Care. 2014;9(6):348-9. doi: http://dx.doi.org/10.13175/swjpcc160-14 PDF