Poorly differentiated squamous cell carcinoma of unknown primary location a case report of perineal presentation

Introduction: Cancers of unknown primary origin (CUP) pose a significant clinical challenge, representing a small percentage (1 to 5 %) of overall cancer cases. The patient is a 31-year-old male who has been diagnosed with poorly differentiated infiltrating squamous cell carcinoma, which has been classified as CUP. The exceptional perineal presentation and diagnostic process serve as a reminder of the diverse nature of CUPs and the crucial role played by advanced imaging methods and a multidisciplinary approach. The inclusion of this case, the seventh one in the literature, deepens our understanding of CUPs. Presentation of case: A 31-year-old man came in with a gradual onset of perineal pain that had been worsening for the past six months. A nodular lesion in the urogenital triangle, infiltrating the bulbo spongiosus muscle, was surgically removed. The histopathology results confirmed a poorly differentiated squamous cell carcinoma. Despite conducting extensive examinations, the multidisciplinary team was unable to determine the source of the tumour, classifying it as CUP. One year post-surgery, the patient remains in complete remission. Discussion: The management of CUPs can be challenging because of the variety of their origins and presentations. The importance of advanced imaging, pathological and biological techniques, as well as meticulous surgical intervention, is emphasized in this case, as it helps in avoiding unnecessary adjuvant therapies. Conclusion: This case highlights the significance of a customized and interdisciplinary approach in effectively managing CUPs, especially when they present in unusual ways. Timely surgical intervention, backed by comprehensive imaging and pathological analysis, can result in positive results.