Thyroid & parathyroid
Benign thyroid neoplasms
Solitary fibrous tumor
Author: Sheren Younes, M.D.
Topic Completed: 1 September 2014
Minor changes: 27 January 2021
Copyright: 2014-2021, PathologyOutlines.com, Inc.
PubMed Search: solitary fibrous tumor thyroid
Table of Contents
Definition / general | Clinical features | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Electron microscopy description | Differential diagnosisCite this page: Younes S. Solitary fibrous tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/thyroidsft.html. Accessed March 4th, 2021.
Definition / general
- Uncommon spindle cell neoplasm at this site, usually with benign behavior
- See also Soft tissue tumor chapter
Clinical features
- Presents as thyroid mass
- Overall most common site is pleura
- Affects adults with mean age 52 years, female predominence
Prognostic factors
- Benign but aggressive behavior when high cellularity, atypia, 4/10 HPF mitosis, tumor necrosis, infiltrating margin (Am J Surg Pathol 1998;22:1501)
Case reports
- 37 year old man (J Cancer 2011;2:206)
- 43 year old woman (Am J Clin Pathol 1994;101:535)
- 51 year old man (Laryngoscope 2009;119:2306)
- 58 year old man with solitary fibrous tumor arising in intrathoracic goiter (Thyroid 2010;20:435)
- 60 year old woman with malignant solitary fibrous tumor of thyroid (Arq Bras Endocrinol Metabol 2014;58:402)
- 61 year old man and 42 year old woman (Head Neck Pathol 2008;2:231)
- 70 year old woman with solitary fibrous tumor of thyroid gland associated with papillary thyroid carcinoma (Thyroid 2006;16:319)
- 76 year old woman with malignant solitary fibrous tumor of thyroid gland (Diagn Cytopathol 2011;39:694)
- Solitary fibrous tumor of thyroid gland (Endocr Pathol 2011;22:165)
- Solitary fibrous tumor of thyroid with capsular invasion (Pathol Res Pract 2003;199:687)
Treatment
- Surgical excision
Gross description
- Usually large, well circumscribed, solid, whitish grey
Gross images
Images hosted on other servers:
Solid, well circumscribed white nodule
Microscopic (histologic) description
- Variably cellular
- Well circumscribed borders, may be jagged with thyroid infiltration
- Patternless pattern, hemangiopericytoma pattern
- Hypo and hypercellular areas, myxoid stroma
- Bland looking spindle cells
- Delicate fibrous stroma
Microscopic (histologic) images
Images hosted on other servers:
Whorled arrangement
CD34, BCL2, CD99, Ki67
BCL2, CD34, CD99, vimentin
Cytology description
- Variable cellularity
- Discohesive spindle cells, elongated cytoplasmic processes, fusiform nuclei
- Collagenized stroma (Diagn Cytopathol 2003;28:213)
Negative stains
Electron microscopy description
- Fibroblasts
Differential diagnosis
- Fasciitis-like papillary carcinoma
- Fibrosing Hashimoto thyroiditis
- Medullary carcinoma
- Other mesenchymal tumors of thyroid (smooth muscle tumors, peripheral nerve sheath tumor)
- Reidel thyroiditis
- Undifferentiated carcinoma
