It has been 12 years since Practical Pulmonary Pathology: A Diagnostic Approach (PPPDA) was first published. We are happy to report that the original version of this book was warmly received, with a distribution of approximately 8000 copies. Readers seemed to find our pattern-based approach to be a useful one in the daily practice of anatomic pathology, judging by the direct feedback we received. We also were honored when PPPDA won the 2005 Textbook of the Year Award from the Royal Society of Medicine and Royal Society of Authors.
In light of these successes, and in view of the fact that hospital pathology continues to grow rapidly in scope and complexity, we decided to prepare a second and now third edition of our book. Several features are new to this edition. A new chapter (Chapter 2) on pulmonary function for pathologists has been added, authored by renowned pulmonary and critical care specialist Dr. Emre Noth. This chapter succeeds and compliments the second edition chapter on chest imaging patterns authored initially by international expert radiologists Drs. Maffessanti and Dalpiaz, now updated under the sole authorship of Dr. Dalpiaz. Both of these chapters help round out the pathologist’s understanding of lung diseases and are critical to the book. Inevitably There have been additions to, and revisions of, the prior text because of advances in our understanding of the pertinent disease processes. Corresponding references have been added, and they are current through 2016. Moreover, many illustrative photomicrographs have been changed in an effort to improve the visual presentation of the topics discussed. Finally, self-assessment questions tied to all the chapters in the current book have been compiled and are available online. It is hoped that these questions will be useful to pathologists in their maintenance of certification and as a reflection of their mastery of the information in the book.
As before, we begin with the general patterns of disease and then add key morphologic findings that assist the reader in focusing on appropriate sections of the book where similar findings are discussed. This approach is facilitated by a structural overlay that limits the patterns. We have found that six general patterns occur, and these are best appreciated at scanning magnification with the microscope. We could begin at an even lower “magnification” using the high-resolution computed tomogram (CT), and this is what our radiology colleagues commonly do as they assemble a differential diagnosis based on observed findings in this medium (see Chapter 4). However, in practice, the CT images may not be readily available to the pathologist at the time the biopsy is interpreted, so for our six pathology patterns, we begin with a tissue section mounted on a glass slide. To help the pathologist in practice correctly identify diseases within patterns, we have included a simple worksheet that emphasizes the importance of knowing the clinical, imaging, and pathologic features in order to arrive at the most appropriate diagnostic category.
An overview of the six patterns is presented, and each pattern is then illustrated in the pages that follow. Most of the patterns were devised to navigate the diffuse lung diseases commonly referred to as interstitial lung diseases or ILD. Given the tumefactive nature of neoplasms, these are heavily represented in Pattern 5 (Nodules), but some nonneoplastic diseases, such as sarcoidosis, nodular infections, granulomatosis with polyangiitis, and certain pneumoconioses, may also manifest as a nodular pattern. Rarely, neoplasms can present as diffuse interstitial lung disease clinically and radiologically.
A basic knowledge of the two-dimensional structure of the lung is essential for accurately assessing patterns of disease. We assume that the reader is familiar with basic lung anatomy by the time a diagnostic problem is being evaluated in the patient care setting, but a brief review is always helpful (see Chapter 1).
Once the overriding or dominant pattern is recognized, the diagnostician assesses the cellular composition and any other distinctive findings that accompany the pattern. In the case of a tumor forming a nodular mass, the presence of prominent spindled cells, or large granular cells, or clear cells provides a direction for creating a differential diagnosis. Within each pattern, we have attempted to use such qualifying elements to direct the reader to the appropriate chapter for further study, reasonably confident that the answer will lie within. For the unusual finding not identified in the list for a given pattern, the reader is directed to the appendix where we have assembled a “visual encyclopedia” of distinctive findings and artifacts.
Naturally, overlap occurs between patterns, and this too can be a useful guide to the correct diagnosis. For example, some infections are both nodular and have airspace filling (e.g., botryomycosis, aspiration pneumonia), whereas others are characterized by acute lung injury and diffuse airspace filling (e.g., pneumococcal pneumonia, pneumocystis pneumonia.) In fact, some diffuse inflammatory conditions in the lung may manifest five of the six patterns in different areas of the same biopsy (e.g., rheumatoid lung). Nevertheless, as more and more information is accrued from the biopsy, the differential diagnosis becomes more limited. In some cases it may be necessary to include several possibilities in the final diagnosis, especially for the nonneoplastic diseases where the effect of ancillary data not available at the time of diagnosis may be very large.
Once again, we are grateful to all of the authors who generously and diligently updated their chapters in the third edition of PPPDA. In addition, many thanks are due to our colleagues at the Mayo Clinic and the University of Virginia for their strong support of this project. Finally, this work could not have reached fruition without the valuable help of our editor, William Schmitt of Elsevier, and the editorial and production expertise of Laura Schmidt and Amanda Mincher.