Skin Cancer: An Interview with Dr Daniel Hohl, Unilabs Pathology

According to the Skin Cancer Foundation, over 8,000 people will die of melanoma in 2024. On Skin Cancer Awareness Month, we interview Dr Daniel Hohl, a distinguished pathologist at Unilabs and a member of the Swiss Society of Pathology, to gain insights into the challenges and advancements in skin cancer diagnosis.  

Can you provide an overview of the different types of skin cancer and their prevalence?

Skin cancer can take various forms and encompasses several types. The three most frequent are basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. BCC tops the list, affecting approximately 30% of individuals at some point in their lives. It can manifest as either a raised bump or a flat, flesh-coloured, or brown lesion similar to a scar.

While less prevalent, SCC still presents a significant risk, with around 10% of people susceptible to it. This type often presents as a firm, red nodule or a flat lesion with a crusted surface.

Melanoma, though less common at approximately 1%, is known for its potential lethality. Originating from melanocytes, the pigment-producing cells of the skin, melanoma frequently emerges as a new spot or an alteration in an existing mole, characterised by irregular borders or a variety of colours.

It's important to note that while these three types represent the primary forms of skin cancer, the skin comprises at least 16 different cellular types, all of which can potentially develop malignant growths, leading to a diverse array and big complexity of skin cancers, including adnexal tumours, sarcoma, and lymphoma beyond the most prevalent ones.

What are the primary challenges you encounter as a pathologist when diagnosing skin cancer?

As a pathologist diagnosing skin malignancy, one of the primary challenges is the complexity of the disease. While there are commonly recognised types, the reality is much more complex. Not only do these main types have subtypes with distinct characteristics, but there are also at least 16 different types of cells within the skin that can potentially become cancerous. Each of these cell types may exhibit unique pathological aspects, making accurate diagnosis a nuanced and multifaceted process. Distinguishing between these various types and subtypes requires a thorough understanding of their histological features, molecular markers, and clinical presentations. Pathologists must employ a combination of clinical information, histopathological examination, immunohistochemical staining, and molecular testing to navigate the complexities of skin cancer diagnosis effectively.

With the advancements in diagnostic technology, how has the accuracy and efficiency of skin cancer diagnosis improved over the years?

Over the past several decades, significant advancements in diagnostic technology have transformed our ability to diagnose and understand skin cancer. One major development occurred in the 1970s and 1980s with the discovery and classification of different types of antibodies, revolutionising our understanding of the immune system's role in cancer detection and treatment.

The classification of the human genome further advanced diagnostic capabilities, enabling scientists to identify genetic markers associated with skin cancer susceptibility and progression.

Immune staining techniques have also played a crucial role in skin cancer diagnosis.

In the last two decades, genetic analysis of tumours has become increasingly sophisticated, with techniques such as polymerase chain reaction (PCR) and next generation sequencing (NGS) enabling the detection of specific genetic mutations and chromosomal abnormalities associated with skin cancer. We're constantly evolving our diagnostic techniques and approaches to stay ahead of these complex diseases.

Are there specific diagnostic techniques or tools that you find particularly useful in your practice for diagnosing skin cancer?

The real game-changer is true collaboration. This collaboration among healthcare professionals is crucial in providing comprehensive care for patients with skin cancer. During my time at Unilabs, I have developed many meaningful relationships with hospital staff, including clinicians. I often collaborate closely with them, requesting clinical pictures to gain a better understanding of each case. One tool I find particularly useful in diagnosing skin cancer is dermoscopy. This non-invasive imaging technique allows for the magnified visualisation of skin lesions, enabling me to assess various morphological features that are not visible to the naked eye. Dermoscopy enhances the accuracy of diagnosis by providing valuable insights into the structure and distribution of pigmented and vascular patterns within lesions. By combining advanced diagnostic tools with collaborative efforts among healthcare professionals, we can ensure timely and accurate diagnoses, ultimately improving patient outcomes.