Solitary Fibrous Tumor (SFT) is a rare mesenchymal tumor (spindle cell neoplasm) originating in body cavity sites, most commonly pleura, peritoneum and meninges or at any site in the soft tissue including seminal vesicle. When arising from the pleura, 13-23% are classified as malignant in contrast to most extrapleural tumors which, with the exception of those of mediastinal origin, have a benign outcome [6]. Most SFTs will present as asymptomatic masses discovered incidentally on chest imaging. Those that do present with symptoms present with nonspecific chest complaints such as chest pain, dyspnea or cough. Intra-abdominal SFT are generally asymptomatic until they reach large enough size to cause mass effect on other organs and localized symptoms like pain, urinary obstruction and constipation. Tumor size at presentation is variable and is typically within a range from 0.8-30 cm(median-5 cm) [7]. Although most SFTs are characterized by a non-aggressive clinical course, malignant transformation and a large size have been associated with a poor outcome, thus making long-term follow-up in all cases strongly advisable. Lesions located in the mediastinum, abdomen, pelvis or retroperitoneum tend to behave more aggressively than those in the limbs. Metastases are most often reported in the lungs, bone and liver. On rare occasions SFT can present with paraneoplastic syndromes, the most commonly described being non-islet cell hypoglycaemia. This is due to tumor production of high molecular weight insulin-like growth factor (IGF), specifically IGF-II [8].

The morphological criterion of all these lesions is represented by a well-circumscribed, tan-coloured, rubbery mass, which is tethered by a pedicle and partially encapsulated. It is described as a ‘patternless’ proliferation of bland-looking spindly to oval epithelioid cells that form short fascicles and/or clusters, admixed with thick or thin collagen bands, and a prominent branching vasculature. Mature adipocytes and giant multinucleated stromal cells may be present [9]. The tumour is difficult to detect because it has no typical radiologic features. Contrast-enhanced CT scan is usually performed: it reveals a well-defined capsule surrounding a nearly homogeneous mass with progressive enhancement from the arterial to the venous phase and occasionally multiple small non-enhancing portions.

In our case study, the general features present were left lower dull aching abdominal pain since 1 month which aggravated on micturition and an abdominal mass. Hence, an adnexal mass was considered. An adnexal mass is a growth that occurs in or near the uterus, ovaries, fallopian tubes, and the connecting tissues. They can be solid or filled with fluid and can be benign or malignant. The differential diagnosis at this point included ovarian mass or cyst with possible rupture, urinary tract infection and inflammatory bowel disease. CT showed a well defined homogenous lesion measuring 6.8 x 4.3 x 6.5cm with multiple vessels.

A pre-treatment biopsy to diagnose and grade the mass is ideal. Because of the unpredictable behaviour of SFTs,, surgery is considered the treatment of choice. The use of chemotherapy is reserved to metastatic or symptomatic non-resectable SFTs, but there are no standard chemotherapeutic indications or regimens. However, the most effective drugs seem to be anthracyclines and ifosfamide, followed by gemcitabine and dacarbazine, which are commonly used in soft tissue sarcomas. Radiation therapy is of some benefit, when used  in combination with chemotherapy [10].