Sunitsch S, Gilg MM, Kashofer K, Gollowitsch F, Leithner A, Liegl-Atzwanger B. Detection of GNAS mutations in intramuscular / cellular myxomas as diagnostic tool in the classification of myxoid soft tissue tumors.
Diagn Pathol 2018;
13:52. [PMID:
30111377 PMCID:
PMC6094570 DOI:
10.1186/s13000-018-0734-8]
[Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND
Intramuscular / cellular myxomas and low-grade myxofibrosarcomas are two different tumor entities with a significant histological overlap, especially if dealing with small biopsies. Despite the morphological similarities, they differ considerably in their biological behaviour. Intramuscular / cellular myxoma rarely shows signs of recurrence and never metastasizes, in contrast to myxofibrosarcoma that tends to recur more aggressively and to metastasize haematologically. Therefore, it is of great importance to distinguish these lesions - evaluation of GNAS mutation status could be of tremendous help.
METHODS
We reviewed 13 cases with intramuscular / cellular myxomas. The 13 cases included 5 men and 8 women, aged from 33 to 71 years (mean age 55.5 years). Immunohistochemistry was performed as well as next generation sequencing. Ten cases were located in the lower extremities and three cases were located in the upper extremities. Two lesions were initially misdiagnosed as a low-grade myxofibrosarcoma.
RESULTS
Performing next generation sequencing 12 out of 13 specimens showed a GNAS mutation.
CONCLUSIONS
Our findings demonstrate that GNAS mutations are more common in intramuscular / cellular myxomas, than had been reported in literature in the past. Next generation sequencing for determining GNAS mutation status on small biopsies or diagnostically challenging cases facilitates the diagnosis of intramuscular / cellular myxoma and separates this tumor entity from its mimics.
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