Extensive leptomeningeal metastases
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The entire cord appears expanded with increased central T2 signal and prominence of the central canal. There is a thick rind of enhancement around the cord post administration of contrast. In addition, there is clumping and enhancement within the cauda equina and nerve roots in the lumbar thecal sac.
Pulmonary metastasis and mediastinal lymph nodes are also noted.
Brain: (not shown)
There has been resection of two of the cerebellar lesions. Once again there are innumerable enhancing intra-axial lesions evident, numbering at least 20. Since prior examination, many of the lesions have increased in size. There is surrounding vasogenic oedema.
No brainstem lesions are identified but there is cord signal abnormality at the cervicomedullary junction. There is also new finding of abnormal meningeal enhancement in the posterior fossa, particularly marked around the brainstem and within the sylvian fissures.
Histology (cerebellar lesions)
MICROSCOPIC DESCRIPTION: All the sections show features of metastatic undifferentiated large cell carcinoma, infiltrating into the cerebellar parenchyma. The tumour forms nodules and solid sheets. No specific lines of differentiation are identified. There are areas of necrosis. The tumour cells appear squamoid in appearance with enlarged nuclei, prominent nucleoli and abundant pale eosinophilic-to-clear cytoplasm. However, keratinisation is not present. Lymphovascular invasion is not seen. Immunostains are to follow.
DIAGNOSIS: Multiple foci of metastatic undifferentiated large cell carcinoma.
SUPPLEMENTARY REPORT: The tumour cells are diffusely positive for CK5/6 and p63. There is focal staining for CK7 and CK14. About 5% of the cells are positive for ER (2+). PR is negative. More than 10% are positive for HER2 (2+, equivocal). CK20, TTF-1, GCDFP15 and p16 are negative. The results are difficult to interpret. Breast carcinoma (with basal-like phenotype) is a possibility. CK5/6 and p63 may be seen in squamous cell carcinomas. Lung or cervical primary would also be in the differential.