PMC6604042_01
Imaging findings of the initial diagnosis.. Primary lung tumor in the right upper lobes on chest computed tomography (red arrow) and its metastatic lesion in 12th thoracic vertebra on spinal magnetic resonance imaging (white arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
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IV adenocarcinoma of the lung and multiple metastases including the brain and the 12th thoracic vertebra (Th12) (Fig. 1). Irradiation of the
Irradiation field of palliative radiation therapy.. (A and B) Irradiation field of 2nd lumber vertebra (L2) and 2nd sacral vertebra (S2). (C) Irradiation region of S2 with around 2 Gy including right iliopsoas muscle.
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Since pelvic pain, caused by bone metastases in 2nd lumber vertebra (L2) and 2nd sacral vertebra (S2), was occurred in 2013, irradiation of L2 and S2 was performed with a total dose of 30 Gy, respectively (Fig. 2).
Location of radiation-induced sarcoma. (A) The lesion (red arrow) with abnormally enhanced signal in right iliopsoas muscle in computed tomogramphy (CT). (B) The lesion (red arrow) with highly enhanced signal in right iliopsoas muscle in positron emission tomography (PET)-CT. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
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In 2018, the patient, now aged 70 years, complained of right mild back pain, caused by the lesion with abnormally enhanced signals in right iliopsoas muscle in CT (Fig. 3A). Positron emission tomography (PET)-CT also confirmed the lesion with highly enhanced signals (Fig. 3B).
Pathological and immunohistochemical examination.. (A) Tumor cells displaying proliferation of atypical spindle cells in a random growth pattern [Hematoxylin and eosin (H&E)]. (B) Most of the tumor cells displaying positive staining for CD34.
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A pathological examination revealed proliferation of atypical spindle cells in a random growth pattern (Fig. 4A). On immunohistochemical examination, most of the tumor cells were positive for CD34 (Fig. 4B), and only limited number of the tumor cells was faintly positive for EMA or desmin.