Home   Case of Week Home   Jobs  Conferences   Fellowships   Books

20 August 2014 - Case of the Week #323

All cases are archived on our website. To view them sorted by number, diagnosis or category, visit our Home Page and click on the Case of the Week button on the left hand side. To subscribe or unsubscribe to the Case of the Week or our other email lists, click here.

Thanks to Dr. Bhavesh Papadi, University of Miami (USA), for contributing this case. To contribute a Case of the Week, follow the guidelines on our Case of the Week page.




Scientific Symposiums International Fall CME Series

Dermatopathologic Dilemmas: Melanoma, Infection and Inflammatory Skin Disease


October 13-16, 2014
The Hapuna Beach Prince Hotel, Mauna Kea Resort, Big Island of Hawaii (USA)


Register for our upcoming Dermatopathology Course course being held this October in order to learn the latest tools for diagnosing Melanomas, Infections and Inflammatory Skin Disease.

Our world-renowned faculty includes Philip E. LeBoit, M. Raman, M.D., Margot S. Peters, M.D., and Whitney A. High, M.D., J.D., MEng.

This course is one not to be missed! Space is limited so register now!

Advertisement


Website news:

(1) Don't forget to check out the Mystery Case on the right side of the Home page.

(2) PathologyOutlines.com celebrates entering into its 14th year of providing a free, online pathology textbook service to the pathology community. We would like to thank all of our users for their support and for making us the #1 online pathology resource for over a decade!

(3) We have now posted the Pathology Jobs Report for the second quarter of 2014, available from the Jobs page or by clicking here. Learn what specialties are hot, and what employers are looking for. We are excited that pathologist job postings are up - increasing 31% from the 65 postings in the second quarter of 2013, and a 47% increase from the 58 postings in the first quarter of 2014.

(4) Visit our Updates page to see what topics have been revised based on reviews or new images.


Case of the Week #323

Clinical History:
A 68 year old man with cirrhosis of the liver due to NASH was found to have a left renal mass in the mid-pole, measuring 2.9 x 2.6 x 2.6 cm. The lesion was 1.6 cm 20 months earlier, and so was suspicious for a renal cell carcinoma. A core needle biopsy was performed.

Micro images:


What is your diagnosis?































Diagnosis:
Xanthogranulomatous pyelonephritis

Discussion:

Immunostains were obtained:

CD68


Xanthogranulomatous pyelonephritis is an uncommon, severe form of chronic pyelonephritis due to infection, stones or other obstruction, but resembling clear cell renal cell carcinoma. Common symptoms include flank or abdominal pain, lower urinary tract symptoms, fever, palpable mass, gross hematuria and weight loss (Arch Pathol Lab Med 2011;135:671), although some patients are asymptomatic (Acta Radiol Short Rep 2014 Jan 3;3(1)). Imaging often shows unilateral renal enlargement and inflammation (J Clin Imaging Sci 2011;1:45). Patients commonly have anemia and leukocytosis, with positive urine cultures for E. coli or Proteus mirabilis.

Macroscopic appearance shows an enlarged kidney with a thickened capsule, yellow nodules with variable central necrosis, and a dilated renal pelvis with stones or purulent material. Histologically, there is replacement of renal parenchyma with CD68+ foamy histiocytes, occasional multinucleated giant cells and inflammatory cells.

Correct preoperative diagnosis is unusual, but focusing on clinical and laboratory findings, including the presence of stones and the association with obesity may be helpful (Int Urol Nephrol 2011;43:15, ANZ J Surg 2014 Mar 25 [Epub ahead of print]). The main differential diagnosis is clear cell renal cell carcinoma, whose cells have clear cytoplasm that may resemble histiocytes, but are usually in compact, tubulocystic or alveolar patterns accompanied by a delicate, chicken wire vasculature. The RCC cells often contain glassy hyaline globules, have nuclear grade 2-3, are keratin+ and CD68-.

Treatment is with antibiotics or surgery.




Nat Pernick, M.D., President
and Shivani Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: [email protected]
Alternate email: [email protected]