From Pot to Print: Using 3D Scanning and Printing to Bring Back Pathology Specimens

Capture a whiff of formalin scent and where does it take you? Many may recall medical school days spent in large, museum-like spaces lined with dark, wood-paneled shelves housing hundreds of jarred or bottled pathology specimens. The smell of formalin pervading the air gave those cavernous rooms a sense of historical significance, telling all who entered that they were in a “hallowed” space. The specimen “pots” themselves were likely collected from postmortems conducted over many decades or even centuries (for instance, the Berlin Museum of Medical History and the Hunterian Museums in London and Glasgow) and were a normal feature within university and hospital pathology departments (1). Medical students used the pots in tutorial sessions or self-directed learning to help them recognize gross anatomical pathology – often forming part of the practical assessments in many pathology courses.

Pathology collections were often amassed in the 18th, 19th, and early 20th centuries, when the study of zoology and other sciences relied upon museum collections that displayed cases of taxidermy specimens. In this period of history, “collect, describe, classify, and display” – often with little accompanying explanation – was the norm. Indeed, many collections arose prior to the era of photography, so it is not surprising that pathology and anatomy departments followed a similar approach and retained a Victorian feel.

Lost in the crowd
In modern medical curricula with case- or problem-based learning, pathology has become largely integrated into the broader curriculum. Pathology – despite it being a large subject incorporating several subspecialties – may not even be identifiable as an academic discipline in some medical schools, and many pathology departments have been reduced in size, combined with related disciplines, or eliminated entirely. In some institutions, pathology teaching has become integrated into clinical environments, such as in tertiary hospitals, where the heavy service loads of diagnostic pathologists may leave them little time for teaching medical undergraduates.

Storage and space constraints have further contributed to reduced reliance on pathology specimens, as have cultural and ethical considerations around the collection and display of human cadaver material. In modern times, many medical schools have repurposed the spaces once occupied by their pathology specimen museums and transitioned to uploading photographic images of historical collections online as learning resources. There are some who still advocate for pathology museums (2) – arguing that the ability to identify and describe gross anatomical pathology is still a relevant and appropriate component of modern medical undergraduate training. However, we must remember that, as well as being important resources for understanding disease pathogenesis, prognosis, and clinical reasoning, pathology collections highlight diseases that have either been completely eradicated or are extremely rare – a constant reminder of the progress we have made in modern medicine.

Seeking specimen solutions
About eight years ago at Monash University, we developed expertise in producing 3D replicas of anatomical specimens using 3D surface scanning, CT scanning, MRI, digital segmentation, and 3D printing. These combined technologies allowed us to produce a collection of 3D-printed normal anatomy replicas (3,4) – including replicas of a human fetal collection (5).

Our experience equipped us with the technical skills and resources to overcome some of the challenges of accurately recreating and replicating color, fine detail, and 3D form, which are considered essential when trying to produce 3D-printed replicas of human pathology specimens. With the lapse in time since our first study, we expected others to have applied this approach to producing human pathology specimen replicas, but – to our knowledge – only one group has since used photogrammetry and powder-based inkjet printers to create replicas of two gross specimens (6). Note that the authors did point out that these may be useful for clinicopathological correlation sessions.

At Monash University, we had a large collection of sparingly used pathology specimens in pots. But because they were collected in another era, they were considered of little value in the modern age of digital technology-based teaching. Before disposing of the specimens, we triaged them – reviewing all of the material and choosing examples of both common and rare pathologies that would be considered useful for teaching if we could replicate them at a suitable level of detail to mimic the real specimen. With full-color surface scanning and high-resolution, UV-curable 3D printers, we were able to do just that.

By translating specimens into a digital – and then inorganic – medium, these 3D prints will allow students to physically handle pathology replicas in facilities other than licensed anatomy laboratories. There will be no fluid-filled pots to handle and no occupational health and safety issues with smelly containers and formaldehyde leakage.

Onwards and upwards
To enhance the utility of the Monash 3D Printed Pathology Collection, we created an updated synopsis for each specimen that includes the clinical history of the patient, a macroscopic description of the specimen, an overview of the disease process, and modern information about disease pathogenesis. The clinical histories written at the time of specimen collection use outdated medical terminology and descriptors that are no longer applicable. The creation of this updated collection, which is by no means exhaustive, gives students the opportunity to hold an accurate 3D replica of, for example, an infant heart exhibiting tetralogy of Fallot, with access to the associated description and individual case history.

So far, we have printed approximately 100 specimens from an original repository of around 1,800 – but, of course, there are many more interesting cases that could be preserved and archived using this approach. Historical collections around the world contain fascinating “potted” pathological specimens that only limited numbers of people will ever see. Now, the technology exists to change this situation; the only barrier is whether institutions will allow specimens to be temporarily removed from their glass containers for radiographic imaging and surface scanning.

We can only imagine the fascinating radiographic data that may be hidden within some of these rare and unique cases in collections across the globe – and, if there is a will for such discoveries, then we have certainly shown there is a way (7).