aneurysmal bone cyst

Definition: Aneurysmal bone cyst (ABC) is a locally aggressive osseous lesion that typically occurs during the first two decades of life.

Examples

 Aneurysmal bone cyst

• https://twitter.com/gmayhall/status/767036580900904960
• https://twitter.com/histiocytosisX/status/1185598608269295616
• https://twitter.com/DanglisFotiosMD/status/795897830649057280
• https://twitter.com/EMadrigalDO/status/846507075547082752

Digital Cases

 HPC:111 (HPC:111): Aneurysmal bone cyst.
 HPC:196 (HPC:196): Aneurysmal bone cyst.
 HPC:201 (HPC:201) : Chondroblastoma with secondary aneurysmal cyst of bone
 JRC:2234 : Aneurysmal bone cyst.

Synopsis

 blood-filled cystic spaces
 intervening septa contain reactive bone, fibroblasts, & osteoclast-type giant cells
 areas of so-called ’ blue bone ’

Variants

 soft tissue aneurysmal bone cyst (extraosseous aneurysmal bone cyst)
 solid aneurysmal bone cyst

Associations

 chondroblastoma (15704086)

Differential diagnosis

 osseous giant cell tumor
 giant cell reparative granuloma (giant cell reaction)
 brown tumor of hyperparathyroidism
 simple bone cyst (solitary bone cyst)
 telangiectatic osteosarcoma
 well-differentiated osteosarcoma

Cytogenetics

 17p13 rearrangements (USP6)

• translocation t(1;17) creating TRAP150/USP6 fusion
• translocation t(3;17) creating ZNF9/USP6 fusion
• t(5;17)(q33;p13) (17378626)
• translocation t(6:17)(p21;p13) (11764383)
• translocation t(9;17) creating OMD/USP6 fusion
• translocation t(16;17)(q22;p13) creating CDH11/USP6 fusion
• translocation t(17;17) creating COL1A1/USP6 fusion

Molecular biology

 variant translocations upregulate USP6 transcription by promoter swapping with the genes ZNF9, COL1A1, TRAP150 and OMD
(15735689)

• translocation t(1;17) creating TRAP150/USP6 fusion
• translocation t(3;17) creating ZNF9/USP6 fusion
• translocation t(6:17)(p21;p13) (11764383)
• translocation t(9;17) creating OMD/USP6 fusion
• translocation t(16;17)(q22;p13) creating CDH11/USP6 fusion
• translocation t(17;17) creating COL1A1/USP6 fusion

 fusion gene in which the osteoblast cadherin 11 gene
(CDH11) promoter region on 16q22 is juxtaposed to the entire ubiquitin-specific protease USP6 (Tre2) coding sequence on 17p13 (15026324, 15509545)

References