Imaging in a rare case of neuroendocrine tumour with skin metastases

Purpose: Disseminated malignancies are a diagnostic and therapeutic challenge that is often encountered in radiology. Finding the primary tumour is crucial for planning proper surgical and oncological treatment. Computed tomography (CT) of the thorax and abdomen is typically the initial examination. However, abdominal magnetic resonance imaging (MRI) or positron emission tomography (PET/CT) or PET/MRI are often subsequently performed. Histopathological examination of metastatic tumours is performed as well, followed by immunohistochemistry. The aim of the report was to present diagnostic workup in a rare case of skin metastases.

Case report: A 72-year-old patient was admitted to a dermatology ward because of skin lesions – violaceous nodules localised on the hair-covered skin of the head. On abdominal CT, a generalised neoplastic process with metastases in the liver, pancreas, adrenal glands, lymph nodes, bones, thoracic wall, and a suspected metastasis in the right breast was revealed. Histopathology of the skin nodules confirmed a neuroendocrine tumour. Metastases of a pancreatic neuroendocrine tumour or small-cell lung cancer were suspected on immunohistochemistry. The patient died before we were able to localise the primary source of the tumour and provide treatment.

Conclusions: Skin metastases are relatively rare, aggravate the prognosis, and usually indicate spread of the neoplastic process in the internal organs. It is not always possible to localise the primary tumour using radiological imaging. In such cases, co-operation with the pathologist is crucial as are the results of histopathological and immunohistochemical examinations.