Diagnosis: Solitary fbrous tumor Sanid. mil. 2019; 75(4) 227 Paratesticular mass The anatomopathological diagnosis was Solitary fbrous tu-mor (SFT) grade 1 of FNCLCC (Fédération Nationale des cen-tres de Lutte Contre le cáncer). American Joint Committee on Cancer (AJCC) 8 th Edition TNM stage: pT2. SFT is a mesenchymal neoplasm and it was frst reported in 1931 as a tumor of the pleura1. SFTs are uncommon that can appear in all sites of body. It represents 5% of soft tissue tumors and only 2% is extrathoracic. The incidence of paratesticular is low2 with 22 cases are reported in the literature3. Most neoplasm has occurred in male with ranges 42 to 67 years old, without predisposing factors, although some papers have associated it with trauma and IgG4 diseases. Typically, it containing a specifc NAB2-STAT6 gene fusion and overexpressing STAT64. Macroscopically, the lesion shows a fbroelastic consistency and a shiny surface. The cutting surface has whorled pattern and yellowish pearly (Figure 1). Microscopically, the tumor is composed by heterogeneous areas settled by a population of spindled cells arranged in fas-cicles or patternless, with an underlying collagen-dense stroma, showing focal hemangiopericytoma-like changes (Figure 2). Immunohistochemically the tumor shows CD34, CD99 and Bcl-2 immunoreactivity (Figure 2, Bcl-2 upper right), in a diffuse and strong pattern. The lesion is negative for epithelial marker (CKAE1/AE3), lymphoid (CD45) and melanic (HMB-45). The cells do not reactivity for SMA, C-Kit, Inhibin, S-100, PLAP, D2-40, CD31, WT-1 and Calretinin. Proliferation index, labelled by ki67 stain, shows a 5-20% rate. Regarding the behavior of this neoplasm, it has been repor-ted that 10 to 15% of extrathoracic SFT will recurs or metastasi-zes, so that strict surveillance is obliged5. The differential diagnosis will include entities such as leiom-yosarcoma, a relatively common mesenchymal tumor in this area, whose origin is smooth muscle. This neoplasm shows a similar histological pattern, but the immunohistochemical pro-fle includes reactivity for smooth muscle actin and negativity for CD99 and Bcl-26. Others differential diagnoses will be neural tumors such as neurofbromas (S-100 positive) and vascular le-sions (CD31 or D2-40 positive). BIBLIOGRAPHY 1.Klemperer P, Rabin CB. Primary neoplasms of the pleura: a report of fve cases. Arch Pathol 1931; 11: 385-412. 2.Yihong Zhou, Guanghui Gong, Yuxin Tang, Jin Tang1, Yu Gan, Yingbo Dai. Paratesticular solitary fbrous tumor: a case report and review of litera-ture. Int J Clin Exp Pathol 2015;8(3):3358-3361. 3.Christopher P. Marquez, Haiyan Zhang, Jason Goodrum, J. Nicholas Sres-hta and Marjan Afrouzian. Florid Proliferation of Hyalinized Vessels in a Spermatic Cord STAT6 Positive Solitary Fibrous Tumor and Its Potential Clinical Implications. Case Reports in Pathology Volume 2018, Article ID 7462032, 6 pages. 4.Chmielecki J, Crago AM, Rosenberg M, et al. Whole-exome sequencing iden-tifes a recurrent NAB2-STAT6 fusion in solitary fbrous tumors. Nat Genet. 2013;45(2):131–132. 5.Gold JS, Antonescu CR, Hajdu C, Ferrone CR, Hussain M, Lewis JJ, Bren-nan MF, Coit DG. Clinicopathologic correlates of solitary fbrous tumors. Cancer 2002; 94: 1057-1068. 6.Mohamad Moussa and Mohamed Abou Chakra Leiomyosarcoma of the spermatic cord: A case report and literature review. Int J Surg Case Rep 2019; 57: 175–178.
RSM_75_4
To see the actual publication please follow the link above