Friday, January 25, 2013

Best Post of August 2012: A case of renal cell carcinoma metastatic to a meningioma

The next in our "Best of the Month" series is from August 9, 2012:

A 74-year-old woman with a history of a seizure disorder had been followed for several years with a stable and unsymptomatic left parasagittal dural-based brain tumor presumed to be a benign meningioma. Recently, though, the lesion increased in size and hemorrhaged, leaving her significantly paretic on the right side. Neurosurgery thereupon performed a craniotomy for tumor removal. Intraoperative frozen section diagnosis was meningioma. But, upon receipt of the permanent sections, I was impressed by the staghorn vessels at low power and hemangiopericytoma immediately came to mind.

Staghorn vessels prominent in region below dot marks
Psammoma body consistent with original impression that this was simply a meningioma
Whirled architecture consistent with meningioma
I was obviously dealing with a meningioma, but something else was going on in that area featuring the staghorn vessels. This region exhibited a different histomorphology:

Clear cells
High-power view of clear cell portion of specimen
This dual morphology puzzled me. I then discovered that back in 2003 the patient had undergone a radical nephrectomy for renal cell carcinoma. Surgical margins of the nephrectomy specimen were free of tumor. I retrieved the 2003 nephrectomy specimen, which looked quite similar to the clear cell portion of the brain tumor:
Nephrectomy specimen from 2003 showing renal cell carcinoma, clear cell type
I thereupon went back to the brain tumor specimen and did some immunohistochemical stains, including RCC for suspected renal cell carcinoma metastasis:
Positive RCC Immunohistochemistry
I had a case of renal cell carcinoma metastatic to a meningioma! Such a case had been reported in the literature before:

Han, HS, et al. Metastatic renal cell carcinoma in a meningioma: a case report. J Korean Med Sci. 2000 October 15 (5):593-597.

Here's case number two!

Follow-up: The patient received radiation to the tumor bed and is recovering.

Thursday, January 17, 2013

Yachnis and Rivera-Zengotita team up to bring us some high-yield neuropathology

Who doesn't love the feel of a brand new textbook in your hands, and that first subtle crack of the binder as you open the cover releasing the synthetic fragrance of smooth new paper? We will get to re-live that feeling when Dr. Anthony Yachnis' Neuropathology: A Volume in the High-Yield Pathology Series is released. The book has a copyright year of 2014, so we may have to wait a while before it is released. But, if the good Dr. Yachnis is the principal author, it will surely be worth the wait. In his preface, written with co-author Dr. Marie L Rivera-Zengotita, Dr. Yachnis writes: "Our intent in producing this volume is not to replace several other outstanding comprehensive textbooks in the field but rather to provide quick reference via bulleted summaries of key facts that are supported by multiple representative photographs on topics of interest in the major areas of neuropathology. We have attempted to provide rapid access to a range of nervous system disorders for trainees and practitioners.... It should be a handy practical reference for practicing pathologists, including neuropathologists requiring quick access to the field" This book does not just cover tumors, but also malformations, cerebrovascular disorders, trauma, infectious disease, demyelinating disease, neurodegenerative disorders, toxic-metabolic disease, peripheral nerve disease, and muscle disease.  I think I can speak for the entire neuropathology community, Dr. Yachnis, in saying that we eagerly look forward to getting our hands on this book.

Friday, January 4, 2013

The biggest Alzheimer Disease discovery in 2012

Kári Stefánsson
Perhaps the biggest discovery in the Alzheimer research world last year was the identification of a mutation in APP that significantly decreases its cleavage by β-secretase, leading to 40% less production of amyloidogenic peptides in vitro. The researchers found the mutation (A673T) in the APP gene protects against Alzheimer’s disease and cognitive decline in the elderly without Alzheimer’s disease.

Future drugs that can recreate this Aβ-reducing effect “should perhaps be given not only to people at risk of Alzheimer’s but to all elderly people,” says Kári Stefánsson, senior investigator of the study, which came out of Iceland and appears online in Nature.