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parotid solitary fibrous tumor

Monday 2 January 2017

solitary fibrous tumor of the parotid gland; parotid SFT

Solitary fibrous tumor is a rare, mesenchymal neoplasm that has been reported in numerous sites. Occurrence in the parotid gland is rare.

Solitary fibrous tumor should be suspected in the clinical context of a slow-growing, well-circumscribed, solid, avidly-enhancing nodule of the parotid gland.

Intimate association with the parotid duct may reflect peripheral entrapment.

Fine needle aspirations that predominantly yield collagen without spindle cell clusters should be correlated with clinical and radiological findings.

Although solitary fibrous tumor of the parotid gland usually exhibits benign behavior, it is best regarded as potentially malignant.


SFT of the parotid gland is a smooth-contoured mass that ranges in size from 1 to 18 cm (average 4.8 cm, median 4 cm) with a white cut surface.


Histologically, parotid SFTs are of the conventional or “fibrous variant” as proposed by Gengler and Guillou.

The tumors have a pushing border and are composed of round-to-spindle cells with bland or vesicular nuclei in a variably collagenous stroma.

In areas of high cellularity, the tumor cells adopt fascicular, herringbone, or storiform architecture. In areas of low cellularity, thick collagen bundles separate the tumor cells. Myxoid stromal change may be found.

Numerous mid-caliber vessels are scattered throughout the tumor and may be elongated or branched with thickened, hyalinized walls. Scattered multinucleated giant cells or a mild lymphoplasmacytic infiltrate may be found.

Focal entrapment of normal serous acini or small ducts at the edge of the tumor is not uncommon.


The immunohistochemistry of parotid SFT recapitulates that of SFT at other sites.

Nuclear expression of STAT6 has been found to be a highly sensitive immunohistochemical marker for SFT and may be useful in small biopsies, CD34-negative SFTs, and distinguishing SFTs from other mesenchymal tumors with significant immunohistochemical overlap.

The tumor cells typically show positive staining for vimentin, CD34, Bcl-2, and CD99, and negative staining for cytokeratin, EMA, CAM5.2, SMA, desmin, GFAP, CD117, and S100 protein.

Differential diagnosis

- nodular fasciitis
- myoepithelioma
- spindle cell carcinoma
- spindle cell lipoma
- spindle cell melanoma
- schwannoma
- desmoplastic fibroblastoma
- dermatofibrosarcoma protuberans
- malignant peripheral nerve sheath tumor (MPNST)


Complete resection is the cornerstone of management. Short follow-up periods (0.1 to 5.6 years) have been performed and most reported patients have no evidence of disease at follow-up. However, rare patients had pulmonary metastases and two patients had a local recurrence.


Predicting the clinical behavior of SFT remains a challenging clinicopathological problem.

Demicco et al. found that patient age (≥55years), tumor size (>15 cm), and mitotic activity (≥4 per 10 HPF) predict the development of SFT metastasis.

See also

- solitary fibrous tumor (SFT)

Open references

- Solitary Fibrous Tumor of the Parotid Gland: A Case Report.
Yu R, Rebello R.
Iran J Otorhinolaryngol. 2015 Sep;27(82):401-5.
PMID: 26568946 Free

- Parotid gland solitary fibrous tumor with mandibular bone destruction and aggressive behavior.
Alonso-Rodríguez E, González-Otero T, Castro-Calvo A, Ruiz-Bravo E, Burgueño M.
J Clin Exp Dent. 2014 Jul 1;6(3):e299-302. doi : 10.4317/jced.51256
PMID: 25136435 Free

- Giant solitary fibrous tumor of the parotid gland.
Chis O, Albu S.
Case Rep Med. 2014;2014:950712. doi : 10.1155/2014/950712
PMID: 25114687 Free

- Solitary fibrous tumor of the parotid gland: Case report.
Sousa AA, Souto GR, Sousa IA, Mesquita RA, Gomez RS, Jham BC.
J Clin Exp Dent. 2013 Oct 1;5(4):e208-11. doi : 10.4317/jced.51103
PMID: 24455083 Free