Small-blue-round-cell tumor explained

In histopathology, a small-blue-round-cell tumour (abbreviated SBRCT), also known as a small-round-blue-cell tumor (SRBCT) or a small-round-cell tumour (SRCT), is any one of a group of malignant neoplasms that have a characteristic appearance under the microscope, i.e. consisting of small round cells that stain blue on routine H&E stained sections.

These tumors are seen more often in children than in adults. They typically represent undifferentiated cells. The predominance of blue staining is because the cells consist predominantly of nucleus, thus they have scant cytoplasm.^{[1] [2]} __TOC__

Examples

Tumors that belong to this group are:

• Desmoplastic small-round-cell tumour
• Ewing sarcoma/PNET^{[3] [4]}
• Neuroblastoma^[3]
• Medulloblastoma
• Rhabdomyosarcoma^[3]
• Synovial sarcoma
• Carcinoid tumor
• Mesothelioma
• Small cell lung cancer
• Wilms' tumour^[1]
• Retinoblastoma
• Small-cell lymphoma^[3]
• Hepatoblastoma^[3] - only the anaplastic form has round blue cells, the more common fetal and embryonal types do not ^[5]
• Merkel cell carcinoma
• Mesenchymal chondrosarcoma

Conditions mimicking SBRCT

Endometrial stromal condensation may mimic a small-blue-round-cell tumour.

Notes and References

1. Gregorio A, Corrias MV, Castriconi R, Dondero A, Mosconi M, Gambini C, Moretta A, Moretta L, Bottino C . 6 . Small round blue cell tumours: diagnostic and prognostic usefulness of the expression of B7-H3 surface molecule . Histopathology . 53 . 1 . 73–80 . July 2008 . 18613926 . 2658025 . 10.1111/j.1365-2559.2008.03070.x .
2. Khan J, Wei J, Saal L, Marc L, Markus R, Peterson C, Chen Y, Meltzer P . Development of a molecular taxonomy of small blue round-cell tumors using cDNA microarrays. Nature Genetics. April 2001. 27. 4s. 64. 10.1038/87150. free.
3. Chen QR, Vansant G, Oades K, Pickering M, Wei JS, Song YK, Monforte J, Khan J . 6 . Diagnosis of the small round blue cell tumors using multiplex polymerase chain reaction . The Journal of Molecular Diagnostics . 9 . 1 . 80–8 . February 2007 . 17251339 . 1867426 . 10.2353/jmoldx.2007.060111 .
4. Grünewald TG, Cidre-Aranaz F, Surdez D, Tomazou EM, de Álava E, Kovar H, Sorensen PH, Delattre O, Dirksen U . 49571421 . 6 . Ewing sarcoma . En . Nature Reviews. Disease Primers . 4 . 1 . 5 . July 2018 . 29977059 . 10.1038/s41572-018-0003-x .
5. Gray W, Kocjan G. Diagnostic Cytopathology; . p.307