Solitary fibrous tumor with neuroendocrine and squamous dedifferentiation: A potential diagnostic pitfall Journal Article


Authors: Lu, C.; Alex, D.; Benayed, R.; Rosenblum, M.; Hameed, M.
Article Title: Solitary fibrous tumor with neuroendocrine and squamous dedifferentiation: A potential diagnostic pitfall
Abstract: Solitary fibrous tumor (SFT) is a ubiquitous mesenchymal neoplasm of deep soft tissue with variable and often unpredictable biological behavior. The lineage is presumed to be fibroblastic, and histological features range from benign to overtly malignant with rare tumors showing “dedifferentiation” or transformation to undifferentiated pleomorphic sarcoma. Dedifferentiation in mesenchymal neoplasms is a phenomenon of histologic progression of a well-differentiated neoplasm to a high-grade sarcoma, which can differentiate along divergent lines. It is extremely uncommon to encounter “transdifferentiation” to non-mesenchymal lineage and still maintaining the driver genetic event of the primary tumor. Herein, we report two diagnostically challenging SFTs with transformation to neuroendocrine and squamous phenotypes. The index case is a pelvic malignant SFT, which metastasized to the liver as a high-grade neuroendocrine carcinoma. The second case is a recurrent brain tumor initially presenting as a typical SFT and evolving into a dedifferentiated SFT with foci of squamous differentiation. Positive immunohistochemical stains for CD34 and STAT6 and the detection of NAB2-STAT6 fusion supported the diagnosis of dedifferentiated SFT in both cases. In the first case, molecular study also demonstrated that both the pelvic primary and liver metastasis harbored the same NAB2-STAT6 fusion. Dedifferentiation to a non-mesenchymal lineage/lineage infidelity can be a potential diagnostic pitfall in these tumors. © 2018 Elsevier Inc.
Keywords: immunohistochemistry; adult; clinical article; human tissue; young adult; clinical feature; case report; brain tumor; follow up; cd34 antigen; liver metastasis; tumor recurrence; pelvis tumor; hemangiopericytoma; solitary fibrous tumor; malignant transformation; neuroendocrine carcinoma; dedifferentiation; cell dedifferentiation; transdifferentiation; squamous differentiation; stat6 protein; human; male; female; article; x-ray computed tomography
Journal Title: Human Pathology
Volume: 77
ISSN: 0046-8177
Publisher: Elsevier Inc.  
Date Published: 2018-07-01
Start Page: 175
End Page: 180
Language: English
DOI: 10.1016/j.humpath.2017.12.024
PROVIDER: scopus
PMCID: PMC6019107
PUBMED: 29309807
DOI/URL:
Notes: Article -- Export Date: 2 July 2018 -- Source: Scopus
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MSK Authors
  1. Meera Hameed
    282 Hameed
  2. Marc Rosenblum
    424 Rosenblum
  3. Rym Benayed
    188 Benayed
  4. Deepu   Alex
    23 Alex
  5. Chuanyong Lu
    9 Lu