Rare Variants of Dermatofibrosarcoma Protuberans: Clinical, Histologic, and Molecular Features and Diagnostic Pitfalls
Round 1
Reviewer 1 Report
This is an excellent paper that might be useful for readers. There is however a misleading statement:
"Unlike classic DFSP, myoid DFSP is characteristically negative for CD34 and positive for alpha-smooth muscle actin, which may be a pitfall in its diagnosis"
It would be important to clarify that only the myoid nodules (probably originated from hyperplastic vessel walls) are actin positive. The DFSP areas are CD34+ and this expression is only lost in areas of sarcomatous transformation.
Author Response
Response to the reviewers’ comments
This is an excellent paper that might be useful for readers. There is however a misleading statement:
We thank the reviewer for this kind comment
"Unlike classic DFSP, myoid DFSP is characteristically negative for CD34 and positive for alpha-smooth muscle actin, which may be a pitfall in its diagnosis"
It would be important to clarify that only the myoid nodules (probably originated from hyperplastic vessel walls) are actin positive. The DFSP areas are CD34+ and this expression is only lost in areas of sarcomatous transformation.
Thank you for pointing it out. As reviewer suggested, we have modified the paragraphs in page 5 as below to make it clear.
“Unlike classic DFSP, in myoid DFSP, the myoid area shows positive staining for alpha smooth muscle actin, and weak or negative expression of CD34, which may be a pitfall in its diagnosis, especially in small biopsy samples. Myoid DFSP has also been reported associated with fibrosarcomatous areas, which usually show loss of CD34 expression17; thus, adequate sampling of the specimen is essential.
Important entities to consider in the differential diagnosis for this variant include cutaneous smooth muscle neoplasms, such as cutaneous leiomyoma and leiomyosarcoma. Leiomyosarcomas show greater cytologic atypia than myoid DFSP, including nuclear enlargement and hyperchromasia, and are more mitotically active. Smooth muscle neoplasms are positive for desmin, while myoid DFSP is negative. In difficult cases, in distinguishing myoid DFSP from these other entities, the detection of the characteristic chromosomal translocation of DFSP (COL1A1::PDGFB fusion) by fluorescence in situ hybridization may be helpful.”
Reviewer 2 Report
Thank you for the opportunity to review this manuscript. This is a well-written review article. The author raised the rare variants of dermatofibrosarcoma protuberans with the differential diagnosis and important criteria to distinguish the rare variant of DFSP from other sarcoma. The figures are very nice to demonstrates histopathology of these rare variants. I have only a comment about the figures. If you can add the magnification of the H&E figures in the figure legends, this will be great.
Author Response
Reviewer-2 comments
Thank you for the opportunity to review this manuscript. This is a well-written review article. The author raised the rare variants of dermatofibrosarcoma protuberans with the differential diagnosis and important criteria to distinguish the rare variant of DFSP from other sarcoma. The figures are very nice to demonstrates histopathology of these rare variants. I have only a comment about the figures. If you can add the magnification of the H&E figures in the figure legends, this will be great.
We thank the reviewer for this kind comment.
We have added the magnification of each picture in the figure legends.
