Solitary Fibrous Tumor of the Sigmoid Colon Masquerading as an Adnexal Neoplasm

Abstract

Solitary fibrous tumor is a rare, benign spindle cell neoplasm that was first described in the thoracic pleura. This tumor is now known to occur at many extrapleural sites. There are established criteria for the diagnosis of malignant solitary fibrous tumor including ≥4 mitotic figures per 10 high-power fields, increased cellularity, cytologic atypia, infiltrative margins, and/or necrosis. Although all solitary fibrous tumors have the potential to recur or metastasize, those with malignant histologic features tend to behave more aggressively. We report a case of solitary fibrous tumor, with malignant histologic features, in a 21-year-old woman which arose from the serosal surface of the sigmoid colon.

A rare solitary fibrous tumour of the ascending mesocolon: a case report

“…Abdominal solitary fibrous tumours have been described in the liver, stomach, kidney, adrenal glands, urinary bladder, prostate gland and uterus. 4 A solitary fibrous tumour in the mesocolon is an extremely rare clinical entity and, to the best of our knowledge, there are only two other cases in the literature, both reporting a tumour in the mesocolon. 2,3 Extrapleural solitary fibrous tumours are most commonly observed in adults with a wide age range of 20-70 years and tend to affect both genders equally.…”

“…1 They are usually slow-growing, painless masses with no clinical symptoms, unless they compress adjacent anatomical structures. 2,4 They can be detected via imaging techniques such as MRI or computed tomography. Macroscopically, most solitary fibrous tumours are well circumscribed, frequently encapsulated masses that are 1-25 cm in size.…”

“…2 The histological differential diagnosis of extra-pleural solitary fibrous tumours includes tumours with mesenchymal contents such as desmoid, inflammatory pseudotumor, mesenteric fibromatosis, gastrointestinal stromal tumour, desmoplastic mesothelioma, leiomyoma and leiomyosarcoma. 4 Immunohistochemical studies are essential to differentiate spindle-cell tumours. A vast majority of solitary fibrous tumours stain positive for CD34, STAT6, Bcl2, CD99, beta-catenin, vimentin and are usually negative for actin, desmin, h-caldesmon, smooth muscle actin and CD117.…”

Solitary fibrous tumour of the sigmoid colon mesentery

“…SFT were originally described in the pleura by Klemperer and Rabin in 1931,4 consistent with most series finding a thoracic origin in up to 70% of the cases (80% pleural, 10% mediastinal and 10% intrapulmonary) 5. Today, SFT are known to arise from many extrathoracic tissues including but not limited to head and neck, retroperitoneum, peritoneum, abdomen, meninges, orbit, upper respiratory tract, salivary glands, thyroid, liver, adrenal gland, kidney, spermatic cord, urinary bladder, prostate, uterine cervix, spinal cord and periosteum 4…”

“…Tumour markers found on SFT include CD34 (present in over 95% of cases) and Bcl-24; however, their lack of expression does not rule out the presence of SFT 10. In fact, low expression of CD34 and high expression of IGF2 are significantly associated with malignant transformation and might be a target of individualised therapy 6.…”