The messenger is fallible

Once the histopathology laboratory delivers the finished slides to the pathologist, the microscope work begins. Depending on the laboratory, a batch may comprise as many as 400 slides. Problems during this part of the cycle may be related to failures of communication or organization, rather than an inability to decipher a slide. Genuinely difficult cases present a diagnostic challenge to all pathologists, for whom help is usually available via a departmental colleague or an external consultant. There is no such thing as “routine” material, but there is a type of specimen from which one would normally expect less trouble. The humbling lesson is that seemingly unimpressive, relatively banal cases will occasionally trap one into a false interpretation. The common hemorrhoid, the inflamed gallbladder, the “ordinary” appendix, the femoral head removed during a reconstruction procedure, all of these common specimens require careful attention. I advise my residents that, when examining slides, they should always be looking for something, and not blankly at something. For example, although bone fractures in the elderly usually result from demineralization, receipt of fracture material from an older person should prompt one to consciously look for a tumor. Still, pathologists are human, and make human errors.  I would go so far as to say that it is impossible to develop into a truly sensitized and mature pathologist without having had at least some searing experiences that drive home the point that no one is immune from making either a serious or trivial mistake.  Here is a memorable one of my own:

In the early 1980s, I received a slide on a patient who had undergone a bladder biopsy. I imagine that I must have been distracted, or busy, or probably both. In any event, I diagnosed a high grade malignant invasive tumor. A week or so later, I received a phone call from a colleague at another institution where the slides had been reviewed. When he said that he could not recognize the malignancy, I asked him to return the slides. On review, I immediately recognized my mistake. What had appeared to be infiltrating malignant cells were suddenly and obviously benign. The pitting depression, anxiety, sense of inadequacy and foreboding that one feels following such a mistake cannot be conveyed in words. A morbid, immobilizing cloud intrudes, and the only way to begin to dissipate it is to share the event with another pathologist. There is, fortunately, a limit to the amount of time that a reactive depression can last, but one is guaranteed to lose at least a week of normal composure in the wake of a blatant error, especially when the clinical stakes are high. In my case, there was some mitigation in that I had not been informed that the urologist had previously instilled an anti-cancer agent into the bladder, a chemical that had ripped up the bladder lining to excite an effect that had simulated cancer. A gratifying resolution came when I picked up the phone and called the patient. I told him, with no uncertain amount of trepidation, that I had completely screwed up the diagnosis. He then went on to say “My father, you know, was an engineer. And one of the things he would tell me is that if a bridge one has built falls, one is inclined to become a better engineer.” He took the whole thing in stride, was extremely gracious, while I was almost in tears. It still moves me, when I think of it.

A diagnostic error must be promptly and appropriately disclosed. In certain clinical situations, symptoms or signs may fluctuate, leading to varying explanations about what is happening to the patient. In surgical pathology it is quite different, because the evidence upon which a diagnosis rests is forever imprinted on the slide and in the paraffin block, and both may be retrieved for re-examination. The main reason that a physician would hesitate in exposing a misdiagnosis is fear of a lawsuit. The fear is realistic, yet the consequences of a cover-up are far worse, and it is therefore always better to pre-empt the later discovery of a genuine mistake by a prompt admission of error, which leads me to the following:

In general, several competent pathologists examining the same slides in a reasonably complex case will not necessarily produce the same language in their reports.  The weight that one pathologist places on an observation may differ from the weight assigned the same observation by a colleague. These are honest and professional judgments that should not lead one to believe that one person is right, the other wrong. These interobserver differences are intrinsic to a field in which a certain level of subjectivity prevails. In most situations, the differences are relatively slight and have no clinical significance. When a really difficult case is shown to several experts, it sometimes happens that their opinions vary sharply, leaving the treating physician in a quandary. For example, I once submitted a tumor to six subspecialists. Three diagnosed a benign lesion, three a malignant condition. Of the first three, one said that the lesion was very benign. Among the other three, one said that it was very malignant. This wide range of discordance is, admittedly, unusual. We reviewed the evidence, weighed our confidence in the consultants, and favored benignity. A radical operation was averted; the patient married his nurse, and has apparently lived happily ever after. Perhaps one should always consult an odd number of experts, thereby at least getting a majority opinion.