SOLITARY FIBROUS SARCOMA: LATE PRESENTATION WITH DIRE EFFECTS

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: A 73-year-old woman with history of breast cancer status post radiation and chemotherapy was eval-uated in our emergency department (ED) for left sided chest pain that worsened over the previous month. She had two weeks of progressive physical limitation, and developed orthopnea the night prior which prompted her to seek care. CASE PRESENTATION: In the ED she was noted to have unrelenting left sided pleuritic chest pain. Physical exam was nota-ble for diminished breath sounds on the left side. Computed tomography (CT) scan of her chest re-vealed a 9.7 x 5.5 cm left lung mass with an associated complex loculated effusion. A left sided chest tube was placed for the loculated pleural effusion. It was exudative by Light's criteria, and pleural flu-id hematocrit was consistent with a hemothorax. She underwent a biopsy of the left lung mass which demonstrated CD34, BCL2, STAT6, spindle cell features and staghorn vasculature indicating a ma-lignant solitary fibrous sarcoma (SFS). She eventually underwent resection as an outpatient once staging confirmed no distant metastatic disease. DISCUSSION: The majority of thoracic solitary fibrous tumors (SFTs) are asymptomatic benign intrathoracic masses discovered incidentally on chest imaging. SFS are a malignant subtype of SFT [1]. Our case demon-strates a rare finding of a large left sided malignant solitary fibrous sarcoma that presented with a large hemothorax. SFTs generally arise from CD34+ dendritic mesenchymal cells which are present in nearly all connective tissues [2]. Association with pleural effusion may be associated with an in-creased risk of a malignant tumor [3]. The presence of a hemothorax has also been reported to cor-relate with rapid tumor enlargement [3]. STAT6, CD34, BCL2 are the most commonly found positive markers, with STAT6 sensitivity being reported as high as 100% [4]. CONCLUSIONS: Our patient did have a history of radiation treatment for left sided breast cancer which has been im-plicated in the development of SFS, particularly in the same radiation fields [5, 6]. Prognosis is usual-ly unpredictable with surgery being the gold standard in treatment [7]. In malignant tumors, chemo-therapy and radiation have limited efficacy [7]. Recurrence rates in malignant SFS are high even with complete resection, reported to be around 63% [8]. REFERENCE #1: Davanzo B, Emerson RE, Lisy M, Koniaris LG, Kays JK. Solitary fibrous tumor. Transl Gastroente-rol Hepatol. 2018 Nov 21;3:94. doi: 10.21037/tgh.2018.11.02. PMID: 30603730; PMCID: PMC6286917. REFERENCE #2: Zuo Z, Zhou H, Sun Y, Mao Q, Zhang Y, Gao X. Rapidly growing solitary fibrous tumors of the pleura: a case report and review of the literature. Ann Transl Med. 2020 Jul;8(14):890. doi: 10.21037/atm-20-4974. PMID: 32793734; PMCID: PMC7396790. REFERENCE #3: Tan JH, Hsu AA. Challenges in diagnosis and management of giant solitary fibrous tumour of pleu-ra: a case report. BMC Pulm Med 2016;16:114. 10.1186/s12890-016-0279-0. REFERENCE #4: Zhang P, Xiong K, Lv P, et al. Malignant solitary fibrous tumor occurring in the mediastinal pleura showing NAB2ex4-STAT6ex2 fusion and negative STAT6 immunohistochemistry: A case report. Thorac Cancer 2020;11:1344-9. 10.1111/1759-7714.13395. REFERENCE #5: Rubino C, Shamsaldin A, Lê MG, Labbé M, Guinebretière JM, Chavaudra J, de Vathaire F. Radia-tion dose and risk of soft tissue and bone sarcoma after breast cancer treatment. Breast Cancer Res Treat. 2005;89(3):277–288. doi: 10.1007/s10549-004-2472-8. REFERENCE #6: Karlsson P, Holmberg E, Johansson KA, Kindblom LG, Carstensen J, Wallgren A. Soft tissue sar-coma after treatment for breast cancer. Radiother Oncol. 1996;38(1):25–31. doi: 10.1016/0167-8140(95)01663-5. REFERENCE #7: Ronchi et al., "Extrapleural Solitary Fibrous Tumor: A Distinct Entity from Pleural Solitary Fibrous Tumor. An Update on Clinical, Molecular and Diagnostic Features. REFERENCE #8: Boothe JT, Budd GT, Smolkin MB, et al. Durable Near-Complete Response to Anti-PD-1 Check-point Immunotherapy in a Refractory Malignant Solitary Fibrous Tumor of the Pleura. Case Rep Oncol 2017;10:998-1005. 10.1159/000484041. DISCLOSURES: No relevant relationships by Danish Ahmad, source=Web Response No relevant relationships by Saad Ashraf, source=Web Response No relevant relationships by Fiyad Haniff, source=Web Response no disclosure on file for Jennifer Toth