Cerebral metastases mimicking multifocal glioblastoma

Case contributed by A.Prof Frank Gaillard

Presentation

Seizure.

Patient Data

Age: 50 years
mmm

Confluent left frontoparietal white matter FLAIR signal abnormality with mass effect and multifocal enhancement within. The high T2 signal change spares the cortex with no evidence of non-enhancing tumour. The largest enhancing lesion measures, demonstrates central non-enhancing cystic components and extends to the corticomedullary junction. No intrinsic T1 hyperintensity. At least five further small foci of nodular enhancement are present through the area of signal abnormality. 

Conclusion

The differential is between a multifocal glioblastoma and a cluster of cerebral metastases. If non-enhancing tumour were present, the diagnosis of a glioma could be made with confidence. Its absence, however, is not as helpful. 

Case Discussion

The patient went on to have a resection. 

Histology

MICROSCOPIC DESCRIPTION:

Sections of brain show a circumscribed deposit of metastatic carcinoma. The biphasic tumour is composed of solid nests of large basaloid cells and focal areas of squamous differentiation. Central tumour necrosis is present. Basaloid tumour cells demonstrate enlarged, oval nuclei with coarsely granular chromatin and small inconspicuous nucleoli. Frequent mitoses and apoptoses are present. Squamoid tumour cells contain abundant densely eosinophilic cytoplasm and prominent intercellualr bridges. No definite keratin or gland formation is seen. 

Immunohistochemical results show tumour cells stain:

Squamous component: CKAE1/3: positive, CAM5.2: positive, CK7: positive, CK20: positive, p63: positive, p40: positive, CK17: positive, CK5/6: positive, CK14: negative.

Neuroendocrine component: CD56: positive, Chromogranin: negative, Synaptophysin: negative.

Both components: TTF1: positive (focal), NapsinA: negative, S100: negative, MelanA: negative, SOX10: negative, p16: positive, EBER-ISH: negative.

FINAL DIAGNOSIS: Metastatic poorly differentiated carcinoma with mixed squamous and large cell neuroendocrine differentiation.

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Case information

rID: 50843
Case created: 24th Jan 2017
Last edited: 26th Jan 2017
Inclusion in quiz mode: Included

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