Scrotal Wall Metastasis from Adenocarcinoma of Unknown Origin, with Concurrent Extramammary Paget's Disease - a Case Report.

INTRODUCTION: Scrotal cancer is a very rare disease, with the most common subtype being squamous cell carcinoma. Metastatic carcinoma to the scrotal wall is very rare. A histological finding of adenocarcinoma in a scrotal malignancy invariably suggests a metastasis from another primary cancer. We describe an enigmatic case of metastatic adenocarcinoma to the scrotum managed as metastatic adenocarcinoma of unknown origin. Attempts to identify a primary cancer were complicated by ambiguous diagnostic results. This is the first case in literature of metastatic cancer to the scrotum from an adenocarcinoma of unknown origin, and this was complicated by concurrent extramammary Paget's disease. CASE PRESENTATION: A 70-year-old male presented with painless progressive scrotal skin swelling, which was shown on histology to be adenocarcinoma. Immunohistochemistry showed prostatic lineage markers. However, the argument for a prostatic primary was weakened by negative prostate transrectal ultrasound biopsy findings and negative radiological findings. The scrotal metastatic adenocarcinoma was managed as metastatic adenocarcinoma of unknown origin. A differential of occult poorly differentiated prostatic primary was considered in view of the clinical phenotype of an elderly male patient with extensive sclerotic bony metastases, immunohistochemistry results and relatively low PSA level in relation to systemic burden of disease. The patient was managed with palliative systemic chemotherapy (carboplatin/paclitaxel) with initial disease response, but eventually developed progressive disease. DISCUSSION AND CONCLUSION: Finding of adenocarcinoma in scrotal skin malignancy indicates a metastasis and should prompt further work-up to identify a primary cancer, particularly of other genitourinary or lower gastrointestinal origin, so that treatment can be targeted at the underlying primary malignancy. However, attempts to identify a primary cancer might be complicated by ambiguous diagnostic results.

Intracranial "white" epidermoid tumours - An imaging approach and systematic review.

INTRODUCTION: Intracranial epidermoid cysts are rare congenital inclusion cysts that can be divided into the classical "black epidermoid" and the exceedingly rare "white epidermoid". White epidermoids are often misdiagnosed because they have different imaging features compared to black epidermoids. There is a paucity of imaging review on white epidermoids. We hereby derive an explanation for the variable imaging features of white epidermoids and propose an imaging approach to distinguish white epidermoids from black epidermoids. METHODS: We conducted a review of white epidermoids in PubMed and Cochrane databases based on PRISMA principles. Qualitative analysis was carried out on the selected cases of white epidermoids, focusing on pathogenesis, imaging features, treatment and prognosis. RESULTS: Out of 1281 studies, we identified 26 full-text articles, comprising 68 patients with white epidermoid cysts, including an illustrative case example from our institution. White epidermoids have completely different MRI signals compared to the classical black epidermoids. Owing to tumour adhesions to the surrounding structures, there is a higher risk of leakage of white epidermoid content during surgery, causing severe aseptic meningitis. We demonstrate an approach to explain the variable imaging features of white epidermoids based on their cyst content - white epidermoids with low T2 signals content often contain high protein levels and viscosity, while those with high T2 signals contain blood products. CONCLUSION: During preoperative planning, it is important to identify white epidermoids. Extensive neurovascular damage should be avoided during surgery given the favourable prognosis of the epidermoids regardless of the extent of tumour resection.