Evidence-based pathology and the pathologic evaluation of Thymomas.
Article Type: Letter to the editor
Author: Rosai, Juan
Pub Date: 12/01/2008
Publication: Name: Archives of Pathology & Laboratory Medicine Publisher: College of American Pathologists Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2008 College of American Pathologists ISSN: 1543-2165
Issue: Date: Dec, 2008 Source Volume: 132 Source Issue: 12
Accession Number: 230246877
Full Text: To the Editor.--I would like to correct a piece of misinformation contained in the article by Gupta et al "Evidence-Based Pathology and the Pathologic Evaluation of Thymomas: Transcapsular Invasion Is Not a Significant Prognostic Feature," published in Archives of Pathology & Laboratory Medicine. (1) In this article, the authors state that "older studies by Levine and Rosai (7) have proposed a classification of thymomas into benign (encapsulated thymoma) and malignant (invasive thymoma) neoplasms based on the evaluation of capsular invasion [italics added]. This concept has been challenged by multiple reports...." As long as we are talking about challenges, I challenge the authors (and readers, if they want to take the trouble) to find any reference to this effect in the article quoted.2 What we stated instead in that article was that invasive thymomas "spread locally in the mediastinum and thorax to involve nerves, vessels, pleura, lungs and myocardium." We were even more restrictive in the Armed Forces Institute of Pathology fascicle on the subject, in which we stated that "it is probably ... justified to label as malignant an obviously invasive tumor which precludes total resection." 3 It seems to me that in both publications we were talking about something a little more substantial than "transcapsular" invasion, a term that the late Gerald Levine or I never dreamt of using.

JUAN ROSAI, MD

Pathology, CDI (Centro Diagnostico Italiano)

20147 Milan, Italy

(1.) Gupta R, Marchevsky AM, McKenna RJ, et al. Evidence-based pathology and the pathologic evaluation of thymomas: transcapsular invasion is not a significant prognostic feature. Arch Pathol Lab Med. 2008;132:926-930.

(2.) Levine GD, Rosai J. Thymic hyperplasia and neoplasia: a review of current concepts. Hum Pathol. 1978;9:495-515.

(3.) Rosai J, Levine GD. Tumors of the Thymus. Washington, DC: Armed Forces Institute of Pathology; 1976:144. Atlas of Tumor Pathology; 2nd series, fascicle 13.

The author has no relevant financial interest in the products or companies described in this article.

In Reply.--The authors are long-term admirers of Dr Rosai's seminal contributions to our understanding of thymic neoplasms and thank him for correcting the apparent misinformation contained in our article. (1) The readers are referred to page 478 of the excellent book Rosai and Ackerman's Surgical Pathology that provides more detailed information regarding the previous classification of thymomas into "benign" and "malignant" lesions: "Traditionally, thymomas of any type (other than thymic carcinomas) that appear totally encapsulated have been regarded as benign, whereas those of similar microscopic types but exhibiting evidence of aggressiveness in the form of local invasion, pleural or pericardial implants, or distant metastases have been designated as malignant." (2) This book quote references the same article listed in our article. All thymomas are currently considered as malignant lesions, regardless of whether they appear as totally encapsulated lesions.

ALBERTO M. MARCHEVSKY, MD

Anatomic Pathology

Cedars-Sinai Medical Center

Los Angeles, CA 90048-1865

(1.) Gupta R, Marchevsky AM, McKenna RJ, et al. Evidence-based pathology and the pathologic evaluation of thymomas: transcapsular invasion is not a significant prognostic feature. Arch Pathol Lab Med. 2008;132:926-930.

(2.) Rosai J. Rosai and Ackerman's Surgical Pathology. 9th ed. New York, NY: Mosby; 2004.

The author has no relevant financial interest in the products or companies described in this article.
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