Medical brain Notes 4

  Safety in the Surgical Pathology Laboratory The key to safety in the surgical pathology labora-tory is to recognize that this area is a dangerous place. A variety of noxious chemicals are rou-tinely used in the surgical pathology laboratory, and tissues infected with the human immunode-ficiency virus (HIV), hepatitis viruses, mycobac-teria, and other agents enter through its doors on a daily basis. Not only are these infectious agents present in the laboratory, but their transmission is also facilitated by the frequent handling of bloody tissues and the routine use of surgical blades, knives, saws, and other sharp instru-ments. Clearly, the surgical pathology laboratory is no place to ‘‘let down one’s guard’’ by becom-ing careless or distracted. Rather, safety in the work area should become an ingrained habit, and universal precautions should be exercised with all specimens. Protective Gear The prosector should regard all tissues as poten-tially infectious, not just those tissues...

  Radioactive Specimens With the increasing use of radioactive materials as a means to identify sentinel lymph nodes, the proper handling of radioactive materials has become an increasing concern in the surgical pa-thology laboratory. Although the risk of signifi-cant radiation exposure associated with these sentinel lymph nodes is believed to be very low, each institution should nonetheless develop writ-ten procedures for handling all radioactive speci-mens. These procedures should be developed in conjunction with the institution’s radiation safety officer and should encompass issues related to the labeling, transportation, processing, storage, and disposal of radioactive specimens. The radia-tion safety officer is also responsible for training pathology personnel regarding safety issues. Do not be shy about contacting your institution’s ra-diation safety office if you have questions about general policy issues or specific concerns regard-ing a radioactive specimen.

  Fundamentals of Dissection At first glance the challenges facing the surgical pathology cutter appear almost insurmountable. The types of specimens that come across the cut-ting table seem endlessly diverse, and the com-plexity of these specimens may at times be perplexing. To top it off, each specimen, whether a simple needle biopsy or a convoluted composite resection, must be handled with equal care and precision. How then does one confidently and effectively function in the surgical pathology laboratory, given the bewildering diversity and complexity of specimens that enter its doors? Where does one even begin? For any specimen, the best place to begin is at the end. Even before making the first cut, take time to visualize the end result of your work, the surgical pathology report. Consider the is-sues that need to be addressed in that report, and then plan a dissection of the specimen that will help address these important issues. While it is true that no two specimens are ex...

  Step 1 .  Specimen Orientation If the surgical pathology report is the end result of the dissection, specimen orientation might be regarded as a road map by which to reach that ultimate destination. With orientation, an other-wise confusing conglomerate of tissue is placed in its proper clinical and anatomic context and appreciated as a structural unit. Then a proper course of dissection can be chartered. Without orientation, specimen dissection can proceed speedily but may never reach its desired aims. The Requisition Form Orientation is usually thought of in terms of the structural anatomy of the specimen. While these anatomic considerations certainly are im-portant, a specimen must also be understood in terms of its clinical context. No specimen should be dissected in a ‘‘clinical vacuum’’; rather, a strategy for the dissection of any specimen should be directed by the clinical history. For example, a uterus removed for leiomyomas is handled very differently from one remo...

  The Cutting Station The cutting station should be clean and orderly. Most routine dissections require a ruler, a scale, a scalpel with disposable blades, scissors, forceps, a probe, and a long sectioning knife. At the begin-ning of each day, the prosector should make cer-tain that these tools are well maintained, clean, and within easy reach. Between dissections, these instruments and the cutting table itself should be rinsed clean of fluids and tissue fragments. This practice will help eliminate contamination of a specimen with tissue fragments from a prior dissection. Similarly, sectioning blades should be rinsed regularly during a dissection so that frag-ments of a friable tumor are not inadvertently transferred throughout the specimen or to other cases. Nothing is worse than not being sure if a minute fragment of cancer on a slide was a “pickup” from another case. No more than a single specimen should be on the cutting table at any one time. Although it may seem time efficien...

  Step 3 .  The Gross Description Correlation between the macroscopic and microscopic findings is important when evaluating a specimen and rendering a diagnosis. Just as glass slides represent a permanent record of the histologic findings, the gross description re-presents a permanent record of the specimen’s macroscopic features. The goal of the gross de-scription is threefold. First, it serves as a descrip-tive report that enables the reader to reconstruct the specimen mentally and envision the location, extent, and appearance of the pathologic process. Second, it serves as a slide index, enabling the pathologist to correlate each slide to a precise lo-cation on the specimen. Third, it accounts for the distribution of the tissue, documenting how a specimen has been apportioned for various diag-nostic and research purposes. To help reconstruct an image of a specimen, the gross description must be logical, factual, and succinct. A logical description is one that follows an ord...

  Step 4 .  Specimen Sampling Mindless sampling of a specimen introduces errors at two different extremes. At one extreme, tissue sampling is inadequate, either because the number of sections is too few or the quality of sections is too poor. In these instances, important issues cannot be adequately addressed in the surgical pathology report. Forgetting to assess a surgical margin, failing to determine the extent of local tumor infiltration, and neglecting to check for metastases to regional lymph nodes are com-mon examples of inadequate sampling. At the other extreme, tissue sampling can be excessive. An inordinate number of tissue sections may exact a costly toll on the resources of the surgical pathology laboratory. The key to an approach that is both economical and thorough is  selective sampling . Selective sam-pling is a strategic approach which attempts to maximize the information that can be obtained from a given tissue section. As opposed to ran-dom and indiscrim...

  The Surgical Pathology Report The surgical pathology report is a comprehensive statement that integrates the macroscopic and mi-croscopic findings. It represents the summation of efforts on the part of the prosector, the histotech-nologist, and the pathologist. Forms are now avail-able that have standardized the reporting of the pathologic findings in a comprehensive way. For the prosector facing a complex and intimidating specimen, the time to contemplate the content of the surgical pathology report is not after the dis-section is completed but before the first cut is even made. With this in mind, this manual describes the dissections of various specimens, including a tabulation of important issues to address in the surgical pathology report. These lists are provided so relevant clinical issues can be kept in mind as specimens are dissected, described, and sampled. Tumor Sampling ·    Sections from the periphery of a tumor are usu-ally more informative than are section...

  General Comments The modern surgical pathology laboratory is equipped to perform a staggering number of routine and special diagnostic procedures. Most are carried out by the laboratory technologist; how-ever, gross room personnel should be familiar with the basic concepts and initial steps of these procedures. Failure to handle tissue appropri-ately may preclude the performance of needed diagnostic studies and ultimately delay or even prevent the establishment of a diagnosis.