Tech Coloproctol DOI 10.1007/s10151-015-1301-x
A rare perianal tumor: solitary fibrous tumor C.-G. Zheng1 • C. Jin1 • L.-C. Ye2 • N.-Z. Chen3 • R. Chen1
Received: 14 February 2015 / Accepted: 19 March 2015 Ó Springer-Verlag Italia Srl 2015
Dear Sir, Solitary fibrous tumor (SFT) is a rare type of spindle cell tumor. SFTs were initially thought only to occur in the visceral pleura and arise from mesothelial cells. However, they have been proven to occur virtually at any site , where they originate from CD34-positive dendritic mesenchymal cells. Extrapleural SFT sites include the mediastinum, the upper respiratory tract, the orbit, and the abdominal cavity, and in these locations, the tumors classified as extrapleural SFTs. Perianal SFT has rarely been reported in the clinical setting. In general, in clinical practice SFT is likely to develop as a benign disease, whereas approximately 15–20 % of SFTs probably recur or even evolve into malignancy . During differential diagnosis, it is highly possible to misdiagnose SFT. The pathogenesis of SFT remains elusive, and symptoms are atypical. Along with the growth of SFT, clinical symptoms induced by tumor suppression may occur. Currently, surgical resection is the primary treatment for SFT, and prognosis depends on complete resectability of the tumor. A 54-year-old woman was admitted to our hospital on January 21, 2013 due to complaints of a perianal lesion for
1 month. A perianal computed tomography (CT) scan revealed a perianal oval tumor, approximately 28 mm 9 32 mm in size. Contrast-enhanced CT detected a significantly uneven enhancement, which was similar on arterial imaging. Pathological changes were present together with encapsulation (Fig. 1). The patient underwent wide local excision of the perianal tumor under lumbar anesthesia. A tumor mass measuring, 4 cm 9 5 cm 9 2 cm, with a complete envelope and surface vasodilatation, was removed. The surgical specimen appeared to be gray-white and have a firm consistency (Fig. 2). Pathological examination revealed that the tumor consisted of abundant spindle cells, which were distributed in a diffuse, weaving, and irregular pattern. Some cells presented with mild to moderate atypia. Signs of karyokinesis 5 \ 50 HPF were observed in a few cells. Interstitial collagenization was noted within the lesions. The tumor was primarily considered aSFT (intermediate type). Immunohistochemistry tests revealed: CD117 (partially ±); CD34 (?); SMA (? in small lesions); S-100 (disperse ?); Desmin (-); Ki-67 (\5 % ?); DOG-1 (-);
& R. Chen [email protected]
Department of Coloproctology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of China
Department of Oncological Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China
Department of Medicine, The Chinese Medicine Hospital of Wenzhou, Wenzhou, People’s Republic of China
Fig. 1 Computed tomography scan revealing an oval retroanal mass
Fig. 2 Appearance of the tumor after surgical resection
SFT can have a widespread distribution and the tumors vary in size. Almost all patients with SFT are asymptomatic during the early stages. Clinical manifestations significantly differ according to the site and the size of the tumor . No specific clinical manifestations of SFT can be observed and there are no characteristic findings on imaging studies. The diagnosis of SFT can be confirmed by histopathological and immunohistochemical examinations combined with the clinical manifestations . In benign SFT, a substantial amount of spindle fibroblasts are observed in a bunch, weaving and ripple array with abundant collagen fibers and excessive scarring. In our patient immunohistochemical analysis revealed CD34 (?), BCL-2 (?), and positive S100 in SFT cells, which contribute to differentiating SFT from alternative types of tumors . The nature of the tumors cannot be accurately confirmed before or during surgery. Consequently, whether the tumor can be completely removed plays a significant role in preventing SFT recurrence. Moreover, long-term follow-up is of significant value. Conflict of interest of interest.
The authors declare that they have no conflict
Fig. 3 Immunohistochemical test revealing positive expression of CD34 (9100)
BCL-2 (?); Vim (?); CD10 (? in small lesions); a-inhibin (-), as illustrated in (Fig. 3). The patient was followed up for 24 months after surgery and no local recurrence or metastasis of SFT was observed.
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