P083 Gnawing at the truth: from ulcers to cancer

Abstract The term ‘rodent ulcer’ historically describes what is now known as basal cell carcinoma (BCC), a common form of skin cancer characterized by slow, locally invasive growth and minimal risk of metastasis. The name, derived from the Latin rodere (to gnaw), alludes to the ulcer’s gradual erosion of tissues. The recognition of ulcerative skin conditions resembling cancer dates back to antiquity. Hippocrates (460–370 Bce) documented destructive skin lesions that prefigured later understandings of malignancy. However, early descriptions lacked the differentiation needed to distinguish BCC from other cancers, such as melanoma or squamous cell carcinoma. The modern history of rodent ulcer began in 1827, when Irish anatomist Arthur Jacob provided one of the earliest clinical descriptions of the condition. He coined the term ‘ulcus rodens’ (gnawing ulcer) to describe the chronic, indolent nature of these lesions. In his own words, ‘The edges are elevated, smooth and glossy, with a serpentine outline; and are occasionally formed into a range of small tubercles or elevations.’ This terminology reflected the clinical presentation of a slowly expanding ulcer with rolled, pearly edges, commonly affecting sun-exposed areas like the face. In 1829, French pathologist Jean Cruveilhier elaborated on the condition in his influential text Anatomie Pathologique. He emphasized its localized tissue destruction and relatively benign prognosis compared with other skin malignancies. These insights laid the foundation for distinguishing BCC from squamous cell carcinoma, which had a higher potential for metastasis. During the late 19th century, advances in histopathology allowed for further classification of skin cancers. BCC was identified as originating from the basal layer of the epidermis or adnexal structures, often linked to prolonged sun exposure. Its slow growth and lack of metastasis distinguished it from more aggressive malignancies. As the understanding of its pathogenesis improved, the term ‘rodent ulcer’ gained widespread use, particularly in British medical practice, to describe the clinical and pathological features of BCC. By the twentieth century, ultraviolet radiation was recognized as a key aetiological factor in BCC, with a higher prevalence in light-skinned individuals with significant sun exposure. Studies also revealed a genetic component, including mutations in the PTCH1 gene and aberrant activation of the hedgehog signalling pathway. These insights provided a molecular basis for understanding the disease’s development and progression. Although the term ‘rodent ulcer’ has largely been replaced by ‘basal cell carcinoma’, the historical term still appears in some clinical and historical contexts. This evolution reflects broader trends in medicine, transitioning from symptom-based descriptors to molecularly informed classifications, marking the ongoing development of medical science.